RCA Antenna Engin7irgFive technical papers by RCA engineers 44%

and scientists #

I 1

Antenna engineeringThis booklet includes five papers that provide a sample of the wide-ranging antenna engineeringdesign and development work carried on at RCA for broadcasting and television stationsthroughout the world, for military systems and for home television receivers.

The Broadcast Antenna Engineering Center is solely concerned with engineering of Antennasystems and the provision of equipment for broadcast and television purposes. Therefore, I havewritten an article (beginning on page 2) which describes the activities of the Broadcast AntennaEngineering Center.

This facility is staffed with dedicated broadcast antenna engineers, scientists and technicianswho are devoted to the creation of antenna systems and products not only for general broadcastand television applications - but also customized antenna arrays to satisfy individual stationneeds ... or the needs of several broadcast and television stations where each has a distinctcoverage contour requirement. The Broadcast Antenna Engineering Center also designs andfurnishes compatible transmission -line equipment, filter -matching networks, and mis-cellaneous accessories that are designed to work together in transmitting the signal from thetransmitter to the antenna.

RCA is in a unique position to act as a single responsible source for all components required in acomplete transmitting system, thus simplifying the work of the broadcast station chief -engineers and consultants who must secure and maintain reliable transmitting systems.

The RCA technical broadcast field representatives listed on the inside back cover of this bookletare capable of working with the broadcast and television engineers and consultants in planningand solving problems of any complexity; these technical representatives are backed up by theservices of the RCA engineers and technicians of the Broadcast Antenna Engineering Centerdescribed in this booklet.

You are invited to contact the RCA broadcast field representative serving your territory whenplanning your broadcast station needs. You will find these men eager to serve you not only inproviding sophisticated broadcast antenna systems but in the provision of all types of a.m., fm,and television broadcast equipment.

R. L. Rocamora, ManagerAntenna Engineering and Product ManagementBroadcast SystemsCommunications Systems DivisionRCA GCS, Gibbsboro, NJ

Our corer

features part of a new broadcast antenna complex be-ing planned for the World Trade Center (New York City)installation. Climbing the antenna are engineer FrankChwieroth (lower left) and wiremen Richard Carver (topleft). Harold James (center). and Harry Crowthers (topright) Photo credit: Bill Eisenberg, GCS. Camden

Report to theEngineering Consultant

Report No. 76

February 15, 1974

RCA ANTENNA ENGINEERING PAPERS

The enclosed booklet contains a collection of five technical papers

by RCA engineers on various antenna subjects.

i)

- _0141

E. N. Luddy

Enc. PE -604

RC/1 CommunicationsSystems Division

-The information contained in this bulletin is furnished as a free service to Engl.neering Consultants. 8y furnishing this information. RCA assumes no obligationor responsibility Any prices which may be mentioned in this bulletin are thoseprevailing at the present and are subject to change without notice at any time"

315128 Rev. 3Printed in U.S.A.

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RCA Antenna EngineeringFive technical papers by RCA engineers and scientists

Contents

RCA's broadcast antenna engineering centerR.L. Rocamora 2

New vhf filterplexerD.G. HymasI J.J. Matta' P.C. Nolel A.N. Schmitz 8

Computer -aided design of vertical patterns for tv antennasDr. Krishna Praba 11

Television receiving antennas in blue and goldJ.D. Callaghan' D.W. Peterson 15

G&CS antenna rangeW.C. Wilkinson 20

International field offices24

Broadcast field officesinside back cover

1

Richard L. Rocamora, Manager, Antenna EngineeringCenter. Broadcast Systems. Gibbsboro, New Jersey.received his degree in electronics from New YorkUniversity in 1946. He also attended graduate courses atthe Polytechnic Institute of Brooklyn and the MooreSchool of Engineering at the Universtiy of Pennsylvania.Mr. Rocamora joined RCA in 1952 with an engineeringbackground which included design experience in relaylogic. power control systems and test instrumentation.His work at RCA included the development and design oftransistorized digital communications equipment. In

1959. Mr. Rocamora was made a leader of this activity. Hewas subsequently promoted to Manager, Digital Equip-ment Engineering of the Communications SystemsDivision. a position he held until 1964. when he assumedhis present duties.

RCA's broadcast antennaengineering centerR. L. Rocomora

This paper describes RCA's Broadcast Antenna Engineering Center where 70 engineersand associated technicians con Dine their talents to design, build, and produce about 20basic types of fm and tv transmilting antennas in addition to custom -engineered antennasystems. Such products vary frj'ri the timeproven RCA Superturnstiles to complex multi -station antenna arrays that satisfy unique coverage requirements for a variety of viewerarea contours. By employing modern computer -aided design techniques, plus full-scalehorizontal- and vertical -radiation -pattern field testing ... upwards of 2000 fm and tvantenna structures and systems have been designed and produced in cooperation withengineers and consultants of the television broadcast industry. Several of RCA's antennadesigns are reviewed in this article, and performance criteria and measurementtechniques are described.

THE RCA ANTENNA EngineeringCenter at Gibbsboro, N. J., started in1954 with a single building and oneantenna-test-positioner (turntable) on afew acres of ground. At that time, onlytwo or three types of broadcast antennaswere being produced.

Today, the Gibbsboro complex encom-passes 135 acres. It includes three largeantenna test sites, two scale -model testsites, and more than 20,000 square feet inmodern engineering labs, machine shops,offices and assembly buildings. TheCenter is now the design, development

and production site for up to 20 basic fmand tv antenna types, associated trans-mission lines, filters, and completecustom -designed equipment systems forlinking transmitter and antenna.

An organization chart of the AntennaEngineering Center and a picture of the

in Figs. 1 and2. The Center employs approximately 70people of which about 25 are engineers.An aerial view of the center is shown inFig. 3.

Final manuscript completed October 26. 1973

Fig. 1 - Gibbsboro staff - from left to right: D.G. Hymas. R.L. Rocamora. Dr. M.S. Siukola. H H. Westcott. and N.Nikolayuk.

2

Antenna design evolution

Early tv antenna designs were omnidirec-tional vhf types with gains of less than 10:a few stacked dipoles were produced, butby far the bulk of deliveries were RCASuperturnstiles.

Superturnstiles

The Superturnstile antenna is con-structed with batwing shaped radiators

stacked one above the other. Because ofits simplicity and superb performance,this pioneer vhf antenna remains todaythe standard of comparison world-wide.Some 700 RCA Superturnstiles havebeen placed in service.

As tv allocations began to escalate infrequency, the need for new designs inhigh -gain antennas became apparent. Onvhf channels 7 to 13, for example, thecomplex mechanical feed system of the

BROADCAST SYSTEMS

N. VANDER DUSSEN

DIVIS:Otv VICE PRESIDENT

TRANSMITTING EQUIPMENT

ENGINEERING AND PRODUCT MANAGEMENT

C.H. MUSSON

MANAGER

Superturnstile tended to limit reliabilityof the antenna. Thus, a simple design withlower wind load was indicated.

TW antennas for vhf

[he low wind load need led to thedevelopment of the Traveling Wave (TW)antenna and the new feed system forwhich it was named.' The rugged,

ANTENNA ENGINEERING ANDI PRODUCT MANAGEMENTWORLD TRADE CENTER PROJECT ANTENNA FINANCIAL PURCHASING

R. L. ROC A MOR A ANALYSIS AND SERVICESH. H. WESTCOTT J. F. TINGLEY R. T. GOLOBERGADMINISTRATOR MANAGER COST ANALYST BUYER SPECIALIST

VHF, UHF ANTENNAS ANDENGINEERING SERVICESN. NIKOLAYUK, LEADER

_Lr ADVANCED ANTENNA DEVELOPMENT

AND SPECIAL PROJECTSM.S. SIUKOLA, LEADER

FM ANTENNAS AND ANTENNA P- RODUCTBROADCAST STATION ENGINEERING I I MANAGEMENT

D. G. HYMAS, LEADER D. S. NEWBORG, MANAGER

Fig. 2 - Gibbsboro antenna engineering and product management organization.

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Fig 3 - Gibbsboro Antenna Engineering Center

tv

enclosed feed system, connected at thebase of the antenna, consists of a singleinner conductor which sets up a travelingwave between it and the supporting outerconductor. Pairs of slots on oppositesides of the cylinder are fed by capacitivepick-up probes. The Traveling Waveantenna not only provides gains of 9 to18. but gives smoother vertical patternsand better circularities than the Super -turnstile. With RCA's 25 -kW trans-mitter, the system achieves the FCCmaximum 316 -kW effective radiatedpower( ER P) for vhf channels 7 to 13 withpower to spare. The TW is still one of themost popular of the vhf high -band anten-nas. Over 110 have been built and in-stalled.

UHF Pylons

Gibbsboro continued its high -gain anten-na development program and, in 1954,scored a major breakthrough in uhfdesign. This antenna, the first ultra -gainPylon for uhf, is a slotted -cylinder type.100 feet high, with nominal gains of up to60.- Again, the radiator is an integral partof the structure, the slots being energizedby a standing wave on the inner conduc-tor. The feed system is a simple designwith built-in provisions for beam -tiltadjustment. The Pylon antenna madepossible the first uhf station with onemillion watts ERP. As a measure ofbroadcast industry acceptance, RCAPylons are in use by the majority of uhfstations in this country; approximately400 have been delivered.

Trends of the "fifties"

Beginning late in the '50's, Gibbsboro

engineers sensed a changing market andresponded with new products to meet itsneeds. The new market needs included:

Increases in ERP and tower heights.Increases in use of directional antennas.More sharing of towers and antennas by

broadcasters or sharing of commontower structures with individual anten-nas.

The station owner's bid for signaldominance (as reflected by the demandfor increases in ERP) resulted in muchoriginal design work by RCA on anten-nas. transmission -line components andsupporting structures. Requirementswere usually for radiating the maximumpower from towers ranging in height upto 2,000 feet. Several installations weremade.

Zee, VeeZee, and Butterflytypes

Although many directional applicationswere filled by the slotted cylinder anten-nas, the radiation patterns of these typessere not optimum in some cases. Thisproblem was met with the development ofa series of uhf andknown as the "Zee". "Vee-Zee" and"Butterfly." Zee and Vee-Zee panelsutilize zig-zag elements.' The Butterflypanel' is based on the hardware of theSuperturnstile. Panels can be face -

mounted from one to five around thetower to provide omnidirectional as wellas directional patterns of any desiredshape. Panel antennas, with their tower -like mainframes, are advantageous inmultiple antenna systems since they canhe used alone or as supports for otherantennas.

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To meet the requirements of multiplestation systems, it was necessary todevelop new antennas as well as modifyexisting designs so they could be stackedside by side, one above the other, orboth.' Auxiliary equipment was alsointroduced to permit stations to shareantennas and antenna apertures.

Broadband fm antennas

With the move to multiple -stationsystems and their ancillary services, theneed arose for a broadband fm antennadesign. Development of a broadband,circularly polarized antenna' made itpossible to radiate both horizontally andvertically polarized fm signals from thesame antenna. This design became thebasis for future multi -station fm systems.

The mechanical and electrical constraintsof stacking antennas on a platform at thetop of a tall tower are numerous. Andwhere broadcast groups form to sharefacilities, individual preferences must bemet, sometimes under the most adverseconditions.

Multi -station arrays andcandelabra designs

All broadcasters in a multi -station systemvie for the same audience. Thus each isvitally interested in. among other things.his coverage and the position of hisantenna on the tower. Since matters ofthis kind are often decided by other thanengineering considerations, the antenna.which for obvious technical reasonsshould be at the top of the tower. mayactually wind up at the bottom. But thedesigner must still satisfy the requirement

Fig. 4 (left) - Side -by -side Candelabra antenna system on tower at Sacramento. California. Fig. 6 (above) - Directionalpatterns of John Hancock Polygons.

4

WFLD-TVCHAN 12

POLYGON

WGN -TVCHAN 9

ZEE PANEL

WMAQ-TVCHAN 6

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WCFL- TVCHAN 38

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Fig. 5 - John Hancock multi -station antenna system.

for a solid structure and provide antennadesigns that assure good performancecharacteristics. This part explains theneed for the wide variety of antenna typesand system combinations.

Obviously the design of multiple -stationtv antenna systems calls for considerableexperience in analyzing the effects ofscattering on the patterns of antennasoperating in close proximity to eachother. This was the subject of intensivestudy' as early as 1957, and the findingswere used for several candelabra designsthat were to follow.

In early installations, specifications ofpattern circularity were verified anddemonstrated by means of scale models.Subsequently, however, equally accuratetheoretical methods of determining gainwere formulated:1 For several years now,these computer -based techniques havebeen used in design and cost estimatingcalculations, and most recently toprovide customized vertical patterns forantenna arrays."

Typical multi -station systems

The first of the multiple -station systems.following the historic Empire StateBuilding array, were the candelabrasconsisting of two or more tv antennas

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Fig. 8 - ML Sutro antenna system.

horizontally stacked on the same plat-form at the top of a tower (Fig 4). RCAhas equipped about 10 of these "side -by -side" systems in this country, using Sup-erturnstiles. Pylons and Traveling Waveantennas.

Typical of more sophisticated designs arethe RCA multi -station systms on JohnHancock Center Building in Chicago,and on Mt. Sutro near San Francisco(Figs. 5 and 8).

Both the 6 -station John Hancock systemand the I I -station (7 tv, 4 fm) Mt. Sutrosystem combine horizontally and ver-tically stacked antennas. The John Han-cock system employs five types, one ofwhich is the new 5-mW uhf Polygon.There are two Polygons on John Han-cock (channels 32 and 44) with patternstailored to direct radiation around LakeMichigan (Fig. 6): This is the first use ofthe Polygon, a 5 -sided self supportingstructure consisting of zig-zag panels.The Polygon has a gain capability of 60,and can be designed for power inputs upto 200 kW.

Antenna performance criteria

All antenna types (Fig. 7) are adjusted forproper input impedance before deliveryto the customer. As to other tests re-quired, RCA broadcast antennas are

categorized as follows:

I) Product -line types requiring no pattern orgain tests. These are the omnidirectional,medium -gain tests. These are the omnidirec-tional. medium -gain Superturnstile.Traveling -Wave and Butterfly types whichhave a history of strict adherence tocalculated radiation patterns and gainfigures. Proof -of -performance tests are con-ducted only at customer request and at extracharge.

2) Product -line types for which verification ofvertical pattern and gain is recommended.These are the omnidirectional high -gainantennas such as the uhf Pylon and Polygon.Tolerances in the manufacture of theseantennas usually contribute to somedeviations from the calculated patterns,making measurement with pattern trimmingadvisable.

3) Directional vhf and 101 types. Pattern andgain tests are required for all directionalantennas which, in addition to their direc-tivity, may have a variable beam -tilt designin the azimuthal plane.

4) Multiple -station systems. Scale models areused to determine the effects of adjacentantennas.

5) Cirt ularly polarized antennas. Special test -procedures include measurements of axialratio and certain other parameters*

SuperturnstileButterflyTraveling WavePylonFM

Fig. 7 - Antennas in production at Gibbsboro.

Zee panelVee-Zee panelPolygonMark 3 panel

5

Measurement techniques

Vertical patterns are recorded with theantenna lying horizontally on a rotatingpositioner. Azimuthal patterns are

recorded on the vertical patternpositioner by rotating the antenna on itslongitudinal axis, spit fashion. Azimuthalpatterns can also be recorded with theantenna mounted vertically on a

positioner. Where size or complexitymake it impractical to mount an antennasystem on standard test facilities, scalemodels are fabricated and tested in freespace. Gain is determined by mechanicalintegration of the recorded patterns.

Throughout pattern measurements, theantenna under test is used as a receivingantenna in accordance with the reciproci-ty principle. Source antennas are selectedand located so as to provide illuminationof the antenna test range. Upon deliveryand erection of an antenna at thecustomer's site, field -service engineersconduct antenna system performancetests. Since all antennas have been ad-justed at the factory for proper inputimpedance, field tests should be minimal.

Systems must be checked after installa-tion of transmission lines to assure thatthere are no excessive discontinuities, aminimum of reflections and low mutualcoupling in the case of multiple in-stallations. An rf pulse technique'? usinga vestigial sideband signal to simulate thetelevision signal is used for reflectiontests. Impedance transformers areemployed when required to achieve op-timum reflection levels.

Antenna center facilitiesThe 135 -acre facility is laid out to providethe best possible conditions for efficientantenna handling and testing (Fig. 9).Included is a model range for design anddevelopment of antennas and filter equip-ment.

The Center is built around two antennaranges, one 18,000 and the other 10,000feet in length. Supplementing the rangesare four antenna positioners, each

tailored for special requirements. Each ofthe following facilities (Figs 10, II, and12) has its own control building equippedwith the most modern measurementequipment available:

I) North Hill is the site of the largestpositioner. This facility resembles a 130 -footlong barge located diametrically on a 90 -foot circular rail track. Positioner capability

TRAMIIRITTIMOWTI

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TURN AAAAAfi CONTROL /LO/.

ANTENNA ENGINEERING CENTERSITE PLAN GIBBSBORO N.J.

Fig. 9 - Gibbsboro facility layout.

Fig. 10 (left. above) - Scaled antenna on model -range positioner. Fig. 11 (right. above) - UHF Polygon on Nolth Hillpositioner. Fig. 12 (above) - Butterfly antenna on Far North positioner.

6

was recently extended to handle antennas aslong as 150 feet and weighing up to 45 tons.\ ntennas for all tv frequencies can he

supported horiiontally up to 25 feet abovethe barge. which has an automatic spitturning system. Also at North Hill is apedestal type positioner which is used forazimuthal pattern measurements and im-pedance testing of low hand vhf antennas.

2)South /lilt is the oldest facility at the Center.l'he positioner at this site is used primarilyfor uhf Pylons and high hand y. hi(TravelingN'avel antennas up to 120 feet long andweighing 15 tons. Panel antennas are alsotested on the South Hill.

3) The Far Vora; facility was added in 1967 toaccomodate increased uhf business, startingwith the Kentucky Educational Sy. stem. Thebasic equipment is a pedestal -typepositioner. A support trestle is normallyused to measure hori/ontally positionedPylon and panel antennas up to 80 feet longand weighing 10 tons. The main pedestalpositioner also serves for impedance andazimuthal pattern testing of verticallymounted massive antennas such as thoserecenth tested for the World Trade Centerproject.

4) The Model Range incorporates two multi -axis positioners for scale model antenna andsystem measurements.

Filters and transmission lineAn equally important assignment of skillsat Gibbsboro is the design of various highpower filters and coaxial transmissionline for use with fm and tv transmittersoperating over the broadcast range of 54to 890 MHz.

Harmonic filters are necessary to reduceharmonic output of fm and tvtransmitters to the stringent levelsprescribed by the FCC. Another type offilter, a combiner, is commonly usedtoday to combine the signals from two ormore transmitters for higher outputpower. A filter of this type was recentlydeveloped to combine the output of three15 kW vhf transmitters into a singleantenna.

The vestigial sideband filter is a singleshaping filter used at the output of thetelevision transmitter to attenuate a por-tion of the visual lower sideband whilemaintaining the passband within a frac-tion of a dB. The diplexer is a form offilter that must be used to combine thevisual and aural transmitter outputs forvhf antennas (such as Traveling Waveantennas) onto a single transmission linefeeder.

The functions of vestigial sideband filter-ing and diplexing have been combined ina vhf filterplexer recently introduced for

the RCA TT-50FH 50 kW transmitter."Filterplexers have been designed to han-dle power as high as 220 kW at uhf.

To meet the requirements of voltage,power and efficiency at these frequencies,filtering elements must he made of coax-ial transmission line secitons orwaveguide cavities, rather than of lessbulky lumped constants. Even so. theheat developed often requires some formof built-in temperature compensation toeliminate filter detuning. One example isthe new high power Filterplexer." wherecavity probes were compounded of Invarand steel to maintain proper length withtemperature change.

New filter designs are assisted by com-puter analysis of mathematical models.They are now air cooled rather than watercooled. The capability of coaxial tv linehas been increased by the use of Freon toaccelerate heat transfer from the inner tothe outer conductor. Proper exploitationof Freon, therefore. may be expected toincrease present power ratings of coaxialtransmission lines and components.

Custom designed systems

Frequently the fm and tv broadcasterdesires a transmitting system differentfrom the standard and tailored to hisspecific needs. To meet this requirementexperienced Gibbsboro engineers workclosely with the customer and BroadcastSales to first define the optimum systemand to set system specifications. Aproposal is then drafted and presented tothe customer.

Upon approval by the customer, thecustom system is then finalized in design.fabricated and tested at Gibbsboro. Onsite installation guidance is often offeredwith the more complex systems.

The custom system engineering ranges incomplexity from transmitting room in-stallation plans showing equipmentplacement and transmission line routing,to RF output switching and logic cir-cuitry for multi -transmitter paralleloperation. Typical systems can be foundin the Empire State Building, John Han-cock Building in Chicago. Mt. Sutro inSan Francisco. New Jersey EducationalBroadcast Facilities, and in most majorcities of the U.S. as well as some overseas.

Several custom systems originally design-ed by Gibbsboro are now being offered as

standard items with current transmitters.For inmance, approximately the first 20paralleled tv transmitters were designedon a custom basis; a standard paralleledtransmitter is currently offered as a

catalog item. A circuit to sensetransmitter exciter output andautomatically switch to a spare in event offailure is now standard with the "F -Line"tv transmitters, while custom packagingof rf output switches in unitized cabinetsled to the standard "OPTO Switch"design for vhf-tv transmitting systems.

Conclusion

I he need for new types of broadcastantennas and associated equipment hasgrown substantially in the last twodecades. The quest for higher power, thedesire of broadcasters to share antennastructures, increased use of directionals,extensive activity in U H F, all have placednew emphasis on design integrity. RCAengineers at Gibbsboro have kept abreastof these requirements by carrying out thefollowing programs:

I) Initiating state-of-the-art solutions tosystem problems.

2) Maintaining a sophisticated test range toverify concepts, and most importantly.

3)Continuing to provide antenna equipmentwith a performance and acceptance recordthat is unmatched anywhere in the industry.

Refereices

I. Siukola. Kumpf. G.A. 'graveling Wave Antenna".RCA Broaltati News April. 19571

2.(ialinus. AT.. "New t'HF TV Pylon Antennas". RCA&Mid( a., Veil, (October. 1967)

.1 (-lark. R.N. Davidson. "the V -Z Punel as a SideMounted Antenna". IEEE Trarmaction, on 811,whaAringIlanuary. 19671

4. Kellam. WK.. Brawn. D.A.."Butterfly VHF Panel Anten-na". RCA Broadratt News (March. 196S1

5 Racamora. R.I... "Managing Multi -Station TV AntennaProjects". 1 he 6th International Television Symposium atMontreus. Swit/erland (May. 19711.

6. Siukola. M.S.. "Dual Polarisation FM Broadcasting witha Single Antenna". RCA Brouaravi Sews done. 19671

7. lien-Dov. 'A New Circularly. Polarized TV and FMPanel Antenna". IEEE Group Broadcasting 22nd AnnualSymposium (September. 19721

N. Newton. Jr.. I. L. Siukola. M.S.. "Predicting OperationalCharacteristics of Closely Spaced Antenna on the SameSupporting Structure". I Ith Broadcast Engineering Con-Icrence at NAB Chicago. (April. 19571

9. Siukola. 64.5., Clark. R.N.. "Various Methoc1s of Deter-mining the Gain of a Proposed UV Antenna". The RCAEngineer t f9691

111 Praha. K. "Computer Aided Design of Vertical Patternsfor IV Antenna Arrays". this booklet.119731

II. Ben -Dos.. 0.. -Measurements of Circularly PolarizedBroadcast Antennas". Fall Broadcast Technic -al Sym-posium (September. 19711

12. Siukola. M.S., "IV Antenna Performance Evaluationwith RF Pulse Techniques". Transactions. IEEE Broad

Suonpmiunt. Washington. D.C.. 1970.

13. Hymns. MG.. Matta. .1.1. Noll. P.C.. Schmit,. A.N.."New VHF Filterpleser". RC.4 Engineer. Vol. IN. No. 5119731

7

New VHF filterplexerD. G. Hymas J. J. Matta P. C. Noll A. N. Schmitz

The recently introduced RCA TT5OFH television transmitters for Channels 7 through 13have a new filterplexer at the output shaping the lower sideband visual signal (5)KW peak)and combining the aural signal (10kW) into a single coaxial transmission ine. Morestringent transmission standards have been introduced with increasingly more emphasison idealized performance in all parts of the transmitter including the filterplexer.

Anthony N. Schmitz. Antenna Engineering Center. Broadcast Systems. Gibbsboro. New Jersey, receivedthe BSME from California State Polytech in 1959. From 1959 to 1963. Mr. Schmitz was with the Missile andSurface Radar Division where he worked on the design of bandpass filters, temperature staolizedklystrons and high power RF loads. Since joining the Antenna Engineering Center. he has been engagedin the design of filterplexers. cavity temperature compensation systems, transmission -line components.3 -dB. couplers, notch diplexers. sidebased filters, antennas and RF load systems. He has a patent for amethod to improve the average power capability of coaxial transmission lines and a patent pending on aheat resistant ferrite coating.

Joseph J. Matta. Antenna Engineering Center. Broadcast Systems, Gibbsboro. New Jersey. received theBS in Physics from St. Joseph's College in 1951. He subsequently completed post -graduate courses inAdvanced Math from the Moore School of Engineering. His experience includes development of highpower RF loads and transitions for the BMEWS project and includes a patent in conjunction wit-i thisproject In Commercial Broadcast TV Systems. he was project engineer for the first high power UHFwaveguide tilterplexer. also FM and VHF notch diplexers. tnplexers. UHF hybrid filterplexer and the VHFcoaxial filterplezer.

Donald G. Hymas. Ldr., Antenna Engineering Center. Broadcast Systems. Gibbsboro. New Jersey.received the BSEE from the University of Alberta. Canada in 1949 and the MSEE from Moore School.University of Pennsylvania in 1960. Following graduation. he worked for Canadian General Electric I rom1949 to 1953 in radio receiver design and on various communication systems projects, the principal oneof which was one linking Pinetree early warning radar sites. Since 1954 he has been with RCA working inthe microwave communications field involving message, data. and television relaying, and since 1970 asLeader in Filter Products, Transmission Line and FM antennas at Gibbsboro. New Jersey Mr. Hynes is aRegistered Professional Engineer of the Province of Ontario and a member of the IEEE.

Authors (left to right) Schmitz. Matta, and Hymas.

MODERN television transmittingantennas for the VHF high -handchannels (such as the RCA traveling -wave antennas) employ a single coaxialline as the feeder from the televisiontransmitter to the tower -mounted anten-na. The visual and aural transmitter out-puts must he diplexed onto the singletransmission -line feeder and in additionthe double sideband visual signal fromthe transmitter must he filtered forming axestigial sideband signal to confine theradiated modulation components withina 6-M Ili channel assignment (see Fig. I).A filterplexer combines the functions ofvestigial sideband filter and diplexer.

I'he electrical operation of the filterplexermay he visualiied by reference to the e-quivalent circuit (Fig. 2). Here, theresonant coaxial cavities actually used inthe filterplexer are represented by lumpedcircuits. The 3-d 13 coaxial couplers used

Final manuscript received October 12. 1972.

Phillip C. Noll. Antenna Engineering Center. BroadcastSystems. Gibbsboro. New Jersey received the BSEEfrom Purdue University in 1952 and MSEE from DrexelInstitute of Technology in 1965. He continued with ad-ditional post -graduate study at the University ofPennsylvania He joined RCA in 1952. working in theVacuum Tube Division at Cincinnati. Ohio. In 1953. hetransferred to the Antenna Engineering Center. Sincethat time, he has participated in design projects onsideband filters. filterplexers, and other high powercircuit components. Mr. Noll's recent projects includeTelevision and FM multiplexing equipment for the newWorld Trade Building in New York City. He is a memberof Eta Kappa Nu, and IEEE.

8

TRANSMITTED

6MHz CHANNEL

Fig. 1 - Idealized transmission characteristics.

at input and output are identified ashybrid I and hybrid 2. These 4 -portdevices may be visualized as tightlycoupled directional couplers that havethe following properties:

Power splittinga)A signal applied at port A divides with half

the power delivered to port C' and half toport D and little or none at port B. Thesignals at ports C and I) are in phasequadrature.

Conthiningb) If equal -power quadrature-phase signals are

applied at port A and B. the signals add atport C and little or none appears at port D.

c) The bandwidth is 30 to 40 M Hz. Despite thephysical length of A 4. the quadrature phaserelationship holds tor frequencies far offhand center.

Diplexingd) From b) above since port D is effectively

isolated from port A. a second signal maybe applied at port D and this signal fromthe symmetrical property of this device willbe divided with half delivered to port A andhalf to port B with little or none to port C.The signals at port A and port B will be inphase quadrature.

Consider now the visual signal applied atport A of hybrid I. The signal splits(quadrature phase, equal power) to feedthe two coaxial lines (A and B), each withfour cavities, series resonated at thefollowing frequencies (referenced to pic-ture carrier):

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NOTCH FREQUENCIES SHOWN ARERELATIVE TO PICTURE CARRIER

CAVITY NO. NOTCHFREQUENCY INNO

HYBRID AURALA 2 0 IN

D C

Fig. 2 - Filterplexer equivalent circuit.

Cavity No. Resonant freq. (MHz)1 -2.052 -1.323 -3.584 +4.5

The four cavities are parallel resonatednear picture carrier. Each cavity places alow impedance across the line at theseries -resonant frequency so the energy atthis frequency is almost totally reflectedhack to hybrid I. The spacing of cavitieson line A with respect to hybrid I, port D,are the same as those on line B withrespect to hybrid I, port C. Therefore, thereflected signal from cavity IA, for exam-ple, adds in phase with that from cavityI B at hybrid I. port B, where theunwanted signal is absorbed in load R I.Very little of this reflected signal is

returned to hybrid I. port A. The portionof the visual signal between -0.75 MHzand +4.18 MHz, relative to the picture-airrier frequency, passes through bran-ches A and B with little attenuation and isdelivered to the antenna at hybrid 2,port C.

The aural signal is applied to port D ofhybrid 2 and is split (quadrature phase, e-qual power) to feed the two coaxial lines-A and B. Most of this signal is reflectedby cavities 4A and 4B and returned to theantenna via hybrid 2, port C. Leakage ofthe aural signal past cavities 4A and 4B isabsorbed in the terminating load R Iconnected to hybrid 1.

Design program

The initial design was assisted by analysisof a mathematical model using a com-puter program developed in Fortran IV.A 2x2 matrix was formed for each of theparallel coaxial lines with cavities. Thesewere combined into a 4x4 matrix whichwas then analyzed in tandem with a 4x4matrix for each hybrid. Cavity slopes,resonant frequencies, and spacings were

ANTENNA

then varied to establish required produc-tion tolerances for the required transmis-sion performance specification.

The next phase of the program was thedevelopment of the resonant cavities withthe required parameters. Particularattention at this phase was directed todesigning safe voltage margins into theproduct. Each of the parallel lines of thefilterplexer must handle 25 kW. peakvisual power. Thus the peak voltage isgiven by

Voeu = N/2 x 25,000 x 50= 1580 V

The cavities were successfully tested witha transmitter at these peak powers. Testswere not extended to actual breakdown,as the transmitter power was notavailable at this time.

A most critical part of the design was thefrequency stabilization of cavities againstambient temperature variation. The prin-ciple used is discussed in the next section.

Principle of cavity temperaturecompensation

The resonant frequency of a cavity can berepresented by a series LC circuit wherethe resonant frequency is a function of theinductance and capacitance of the cavity.The inductance L is a function of thelength the probe protrudes into the cavityand the capacitance C is a function of thegap between the probe tip and the cup. Asthe ambient temperature rises, the outershell of the cavity and the probe increasesin length causing the cavity to detune.

The problem then becomes one of con-trolling the probe length so the productLC remains constant. This was ac-complished by making a compound rodwith a portion of the length of invar andthe remaining portion steel. Typical fre-quency shift curves are shown in Fig. 3.

9

Table I - Filterplexer specifications. channels and effective isolation betweenthese channels.

NewFilterplexer

Previousproduct

fowl amplitude response(dB norittakedt

-4.25 to -1.25 MHz-3.58 MHz-0.75 to 4.0 MH/

MHz0 to +4.0 MHz+4.18 MHz

-2o -20-42-0.6

-42

-0.75+0.3 to -1.0

-1.5

Input return loss NipI usual-4.25 to -1.25 MHz-1.25 to +4.0 MHz+4.0 to -4.18 MHzAural

20.931

26.520.9

20.926.523.220.9

LlinWHIT /Visualaural

95.5 9490 92

Size litWxH 96x47x34 90x87-1, 2x29

Cooling Forced air Water

All cavities are cooled from a singleforced -air blower and manifold dis-tribution system properly portioning theflow to cavity pairs in relation to the heatdissipation requirements.

The probe is designed so that the powerlosses (due to heating of the probe assem-bly) influence the compensation. Air thatis heated in proportion to power losses iscirculated around the compound rod.Thus stabilization is optimized forvarying power input level to the cavity aswell as varying ambient temperatures.

"This portion of the design program wasaccomplished in the following sequence:

I) Analysis of mathematical model of eachcavity which included the temperaturedistribution along the cavity axis and radialdistribution.

2) Synthesis of a model in breadboard form.using suitably placed heaters to achieve thetemperature distribution postulated in themodel.

3) Temperature compensation ofbreadboard.

4) Power tests on the cavity model.5) Selection of air-cooling system with

proper manifolding for the completefilterplexer.

6) Power tests on the complete filterplexer.

Performance standards

the

What are the ideal standards forfilterplexer performance and how closelyare they approched with the new model?The standards are based on transmissioncharacteristics for visual and aural

-The Federal Communications Com-mission, the regulatory body governingdomestic broadcast transmission,specifies that the shape of the transmittedvisual channel shall he in accordance withFig. I. This illustrates the lower sidebandshaping of the amplitude modulatedvisual signal required to confine theradiated modulation components in theassigned 6 -MHz television channel band.

In addition to the amplitude shaping re-quirements, the filterplexer must providea good impedance match throughout themodulation band to the transmitter andmust have low attenuation (hightransmission efficiency) at the visualchannel carrier frequency.

The aural channel requires no amplitudeshaping: however, a good impedancematch and low attenuation must heprovided across a band of ±50 kHzcentered at picture carrier frequency plus4.5 MHz. The standards on isolationbetween visual and aural channels are setby the transmitter designer to:

I) Control level of intermodulation productsthat may be generated in the transmitter

Table II - Filterplexer measured data.

FrequencyRel. topie carrier

New product. Previous product.than. 8 than. 8

M H r) Normalized NormalizedAllen. 1SW R Aura. VSWR418) (i/H)

-4.5 21.7 1.03 25.6 1.03

-3.58 54.8 1.02 51.6 1.03

-3.2 31.1 1.01 21.6 1.025

-2.75 26.5 1.02 21.1 1.025

-2.05 57.2 1.035 20.6 1.02

-1.42 - 42.6 1.01

-1.6 21.7 1.050 42.6 --1.32 36.0 1.070 --1.25 21.0 1.065 21.6 1.01

-1.0 2.7 1.040 10.4 1.02

-0.75 0.3 1.040 3.6 1.03

-0.5 0 1.035 0.4 1.02

0 0 1.035 0 1.02

0.75 0 1.035 0 1.04

1.75 0.1 1.045 0.6 1.06

2.75 0.28 1.045 0.8 1.09

3.25 0.32 1.040 0.8 1.10

3.75 0.21 1.035 0.6 1.10

4.0 0.47 1.020 0.2 1.08

4.18 0.95 1.035 1.0 1.14

4.5 25.6 1.125 31.7 1.24

4.75 6.4 1.092 10.5 1.11

/solorion (t/8/ 36.4 31

Visual to Aural 36.41 31

Aural to Visual 50 47

Lytictettcc tqlAural 90 91

Visual 95.5 95.5

Aural VSWR 1.02 1.17

output amplifiers if such isolation is notprovided. These products may be radiatedif not properly attenuated in the design.

2) Minimize effect on the output meteringcircuits of visual and aural transmittersparticularly those monitoring output loadVSWR.

A comparison of specifications for thenew filterplexer and those for the

predecessor are shown in Table I.

Measured performance data on a produc-tion unit are shown in Table II togetherwith corresponding data for the previousproduct.

Principal differences in this design fromprevious units are the following:

I) Addition of pair of cavities in the lowersideband to improve the response at -0.75MHz.

2) Improved passband response.3) Use of 3-dBcoaxial coupler instead of bridge

diplexer. This resulted in a more compactassembly despite the two additional cavities.

4) Forced -air cavity cooling instead of water.5) Cavity temperature compensation.

Conclusions

Some of the design considerations of atelevision transmitter filterplexer havebeen described. Emphasis in thedevelopment program was placed onperforming full power tests on cavitymodels as early in the program as possibleto verify calculated voltage margins andtemperature compensation requirements.Full power tests were also performed on acomplete filterplexer prior to productionfor customer orders.

Future improvements in the design areunder review. Significant product costreduction might he achieved with theadvent of high power circulators toisolate transmitter output amplifier fromthe filterplexer. With the consequent pos-sible relaxation of input impedance re-quirements three visual cavities might heeliminated in the present eight cavitydesign. Improvements in material platingtechnology are being studied for possiblelower cost substitutes for copper presen-tly used in the cavities for high electricaland thermal conductivity as well as struc-tural strength.

Acknowledgment

This development program was initiatedunder the direction of Roger E. Wolfnow Manager Television TransmitterEngineering Meadow Lands, Pa.

10

Computer -aided design ofvertical patterns forTV antenna arraysDr. Krishna Praba

A method for filling nulls in the vertical pattern of a broadcast TV antenna has beendeveloped and applied. This computer -based technique. now being used by theCommunication System Division. compares favorably with other methods. The com-puter program is versatile and the synthesis technique has been especially success-ful since the designer is in the decision loop. However. further work is needed toimprove the optimization methods.

SI VERAL METHODS of synthesizingthe vertical patterns of antenna

arrays for television broadcastinghave been developed."" All of themrefer to arrays having identical ele-ments. In arrays consisting of panelsthat are themselves several wave-lengths long, the vertical pattern ofthe panel itself may have, in effect, anull in the region of interest. To avoidsuch a null, the array can be made upof shorter panels, but the number offeed points is increased thus reducingreliability. Another method for over-coming the problem is to combine oneshort panel with several longer panelsto make up the aperture. This combi-nation of short and long panels estab-lished a need for a general method ofsolving a variety of null -filled patternswith simplified illumination currents.A computer -aided design techniquewas developed a few years ago to

Final manuscript received October 12, 1972.

Dr. Krishna Praha(formerly Dr. P. B. Krishnaswamy)Antenna Engineering CenterBroadcast SystemsGibbsboro, N. J.received the BSc in Physics from Madras Univer-sity (India) in 1951, the MSEE from PrincetonUniversity in 1962 and the PhD from the Universityof Pennsylvania in 1964. Prior to joining RCA. hewas associated with Fischer 8 Porter Co., War-minster, Pa. where he developed flow instrurrentsand process control systems, and with Drexel In-stitute of Technology as an Assistant Professor ofElectrical Engineering. Since joining RCA in 1967.he has mainly been responsible for analyticalwork on antenra arrays. He has developed severalcomputer programs for antenna design and hasworked on the various multiple antenna installa-tions that have been developed, or are under de-velopment, by the Antenna Engineering Center.He has published several papers on the aoovesubjects and holds five U.S. Patents. Dr. Prabais a member of IEEE. a member of Sigma Xi. anda fellow of the British Computer Society.

assist in the synthesis of such arrays.The program, now available on atime-sharing terminal, allows the userto fill the nulls to the desired extentand also to reduce side lobes. Whennecessary, constraints may be imposedon the amplitude or phase of the cur-rents in one or several panels.

The magnitude of the unfilled arraypattern around the main beam is, ofcourse, considerably greater than thatat other angles. Further, the mainbeam may be tilted to any desired lo-cation by progressively phase -shiftingthe currents of the panels. A null -filledpattern can be considered to be madeup of an unfilled primary patternwhose main beam is located at thedesired angle and one or several moreunfilled patterns whose main beamsare located at the primary patternnulls to be filled. The illuminationcurrents for the final pattern are thesum of all these illuminations. Adjust -

MoatMaas1111111111

111111111 I

U.MO

et

.f Aliru

e a

11

I

11

07-41 06-cVV

L.1

_ex 0.3

EQuISPACED ARRAY

SPACING 6.0 WAVELENGTHS

PANEL AWL- PHASE

NO ITUDE IDEG.1

DEGREES FROM HORIZONTAL

.0 0.00 0.0.0

.0.0

.o

0.00.00.00.0

Fig. 1-Uniformly illuminated equiphaselarray.

ment of the phase of the secondaryilluminations results in reducing orincreasing the magnitude of the pat-tern at the desired angle, thus accom-plishing null fill or side -lobe reduction.In general, the starting point is notrestricted to unfilled array illumina-tion. Thus, previous solutions can beimproved upon, reducing the solutiontime considerably.

The technique compares favorablywith all the other methods and hasbeen extensively used in antenna arraysynthesis. When the current in a panelis constrained in magnitude or phase,that particular panel current is read-justed to the constrained value. Themethod is faster in that the null fillingis restricted to the desired nulls only,instead of specifying the entire range.In addition, no gradient calculationsare necessary, as is the case in steepestdescent techniques.

General considerations

The vertical pattern P(0) of an an-tenna consisting of N panels, at adepression angle 0 is given by

N

Plei = p1(8)A, expaiod

exp [j(27/X)] di sin e(1)

where p.(0) is the vertical pattern ofthe i'6 panel; Ai is the amplitude ofthe current in the i'" panel; 4I is thephase of the current in the panel;and d is the location of the i'h panel.In TV applications, only the normal-

ized magnitude of the pattern is ofinterest.

For an array consisting of N identicalpanels spaced uniformly apart andcarrying identical currents, the expres-sion of the vertical radiation patternis given by

IP(8)I-ip 09 I I sin[ (Nrd/X)sin 0]/N sin [ OrdIx) sin e]

(2)

where p(0) is the vertical radiationpattern of the panel and d is the spac-ing. When p(0) is a constant (unitysince it is a relative field pattern), thefunction P(0) repeats itself for everyAid in sin 0 and has nulls at (Nd sin0/A.- ±m, for m=1, 2, 9. A plot ofEq. 2 for p(0) -1 is available in manytexts.' The unfilled pattern for a six -layer Zee -panel array is shown inFig. 1.

To provide adequate coverage fortelevision broadcasting, the nulls inthe radiation pattern in the coveragearea cannot be tolerated. In mostcases, the customer specifies the ex-tent to which the nulls are to be filled.The desired amount varies with thetype of coverage area, their distancesfrom the antenna, the height of theantenna, its effective radiated power,etc. The desired pattern to achieve a100-mV/m signal in the coveragearea, is shown in Fig. 2, based on theFCC data."

Any specified tilting of the beam be-low the horizontal is easily achievedby progressive phase shifting of thecurrents in each panel by an amountequal to -2 (7r/A.) d. sin Or, whereOr is the required amount of tilt.Minor corrections, necesssary to ac-count for the panel pattern, can beeasily determined by iteration.

When the nulls of a pattern are filled,the directivity of the pattern is re-duced. This reduction in gain is to bekept as low as possible. A typical gainloss of 1 to 2 dB is generally encoun-tered.' A good approximation of thegain reduction is the ratio of the beammaximum of Eq. 1 to that of an arrayin which the beam maximum is maxi-mized for the same power input. In auniformly spaced array with identicalelements, the beam maximum is maxi-mized when all the currents are equalin magnitude and the beam is tilted to

0.9

02

0.1

ABOVE

03BELOW

REQUIRED RELATIVE FIELD

PATTERN TO MAINTAIN

A FIELD OF 100 W./METER

FOR AN ANTENNA WITH AN

EFFECTIVE RADIATED POWER

OF 1000 RI, ASSUMING CENTER

Of RADIATION TO BE 1300'

ABOVE AVERAGE TERRAIN.

I BASED ON FCC DATA)

10 I 2 3 6 3 6 7

DEGREES FROM HORIZONTAL

Fig. 2-Desirable relative field pattern.

9 40

coincide with the maximum of theelement pattern.

In the case of an array with two dif-ferent element patterns, the powerinto the panels is to be proportionalto the gain of the panel pattern, as-suming that the panel beam tilts arethe same and mutual coupling be-tween panels can be neglected.

In some cases, it is not only necessaryto fill the nulls, but it is also desirableto reduce the levels of the sidelobes,so as to increase the gain of thepattern.

Null -filling methods

The variables available for patternnull filling are the spacings of thepanels and the amplitudes and phasesof the exciting currents. The spacingsare generally chosen for the full utili-zation of aperature and the gaps be-tween the panels are just sufficientto reduce mutual coupling betweenadjacent panels. Hence, the onlyvariables available are the 2(N-1)amplitudes and phases.

In split -feed systems, one of the sim-ple methods of null filling is by powerdivision between the panels. For ex-ample, a 70:30 power division be-tween each half of the array producesa 13% fill of the first null, but theeven nulls are not filled. If this methodis extended to fill all the nulls, theresultant power division is not accept-able in practice. But power divisionis usually employed where only thefirst null is to be filled. A typical pat-tern is shown in Fig. 3.

12

EOUISPACED ARRAYSPACING 6.0 WAVELENGTHS

PANEL

NO

AMPLITUDE PHASE

I DEGREES I

1 655 0.02 655 0.03 .655 0.04 1-000 005 000 0.0

6 000 0.0

DEGREES FROM HORIZONTAL

Fig. 3-Equiphase array with power division.

A similar approach to null Idling bychanging the phases of the currents isvery useful, since the power fed tothe antenna is maximized. In an arrayare equal for maximum power input;in some other arrays. the amplitudesare adjusted in proportion to thepower ratings. For example, if thebottom and the top layers of an N -layer array differ in phase by 95 fromthe rest, the first [ (N/2) -1] nulls arefilled. The amount of null fill is ap-of identical elements, the amplitudesproximately

(4/N) sin (0/2) cos [rNd sin 19/X]

The side -lobe levels tend to be high.

One of the classical methods of nullfilling in which both phases and am-plitudes are modified, is the "Wood-ward Quadrature Method.' The suc-cessive nulls are filled by the elemen-tary uniform array which is shiftedby progressive phase to the requirednull location and is in quadraturewith the main illumination. The solu-tion is the algebraic sum of all suchelemental illuminations. The methodhas been used successfully in the de-sign of antenna arrays." Generally,one has no control on the side lobesand constraints are not applicable.Equal amplitude constraint can alsobe imposed by correcting the ampli-tudes of the current back to unity .°

Computer -aided design

The following method is similar to"Woodward's" procedure except thatthe quadrature requirement for the

null filling part of the illumination isremoved. A plot of the array pattern,as in Fig. 1, indicates that the magni-tude around the main beam is con-siderably greater than that at otherangles. The panel element pattern fur-ther enhances this effect by reducingthe secondary main lobes as well. Themain beam is shifted to any depres-sion angle 0 by progressively phasingthe panel current by an amount equalto (-277di/A.) sin 0. If the pattern isto be raised or lowered at any angle 01,,a second illumination of the arraywith a progressive phase shift in thecurrent and an additional constantphase is added to the primary illumi-nation. In this case, the current I inthe panel i is modified to

11=A1 expace0+ k cxpAr-r

1[(-2'7/x)d, sin 4. cc]

(3)

If a is in phase with the pattern cor-responding to all the A, and 4) . theresultant pattern due to the newcurrents is increascd by an amountproportional to k at If a is out ofphase, the resultant pattern is re-

duced. If k is proportional to A,. thenormalization is accomplished. Minorvariations in the pattern around theangle can be accounted for by suc-cessive iterations. If the currents are

START

ELEMENT PATTERN(S)SPECIFIED

NULL FILL GAIN

'SEARCH DATA FILE

<SE F UL PATTERN

InoCHOOSE ITUELIL LuMINATiON

THESISE REO '0NU L FILL

R DNULL FILL

SYNTHESISEUN R

CONSTPIAINTS

CHOOSENE w STARTING

POINT

T.

CONSTRAINTS

SAgSititY)T

INSPECTILLUMINATION

NT)POSSIBLE

Fig. 4-Computer aided pattern synthesis.flow chart.

0.11

0.7

re 0.6to5

ad 05

IJ0.4

a 03

Q2

0.1

EOUISPACED ARRAY

SPACING 6.0 WAVELENGTHS

PANEL AMPLITUDE PHASE

NO (DEGREES I

I 1.0 -30.02 1.0 0.03 1.0 0.04 1.0 0.05 1.0 0.06 I.0 -30.0

0 I 2 3 4 5 6 7 8 9 10 11

DEGREES FROM HORIZONTAL

Fig. 5-Unitormly illuminated array with vari-able phasing.

to be fixed in any of the panels (forexample, in the case of power con-straint), the magnitude of the currentis readjusted to the original value. Insuch a case, the resultant pattern im-provement is reduced and more thanone iteration is necessary. It has beenfound that the number of iterationsto arrive at final solution are re-duced considerably if a partially filledpattern is chosen as a starting point.Hence, most of the derived solutionsare generally stored for future use asa starting point.

Results

A computer program (Fig. 4) usingthe above method has been in use forseveral years. The following examplesare illustrative of the results that havebeen obtained.

Example 1 (Fig. 5): With all the ampli-tudes equal, the first two nulls arefilled by phase perturbation of the topand bottom panels of a six -layer an-tenna. This solution is often used as astarting point, as is the case for exam-ples given below.

Example 2 (Fig. 6): The third null isfilled by shifting the pattern to the de-pression angle where it occurs with anin -phase illumination. Two iterationsteps were required to achieve 5%null, since all the amplitudes were con-strained to be equal.

Example 3 (Fig. 7): From the above pat-tern, all the nulls were raised by re-moving the amplitude constraint. Asecond iteration was needed to raisethe fourth null to 7.5% from 4.7%.The maximum power in any panel is

13

02

01

0 LASOVEBELOW

L X I I5 2 1 0 1 2 3 4 5 6 7 11

DEGREES FROM HORIZONTAL

EOUISPACED ARRAY

SPACING 60 ViAvELENGTHS

PANEL

NO

AMPLITUDE PHASE

(DEGREES)

0 -5642 10 67

0 -7 6o 40

5 1 0 -7 66 1 0 -500

10 II

Fig. 6 -Uniformly illuminated array with vari-able phasing. improved.

24o instead of 16.7% in the equal -

amplitude case.Example 4 (Fig. 8): The second lobe at

33° below the horizontal in example 3is almost equal to the first lobe at2.2°. This was reduced to produce asmoother pattern. Two iterations wererequired to keep the nulls filled to thesame level.

Example 5 (Fig. 9): In this high gainantenna consisting of eleven panels,one of the middle panels is shorter thanthe other panels. The longer panelshave a null at 9°. The array is tilted to0.75° and the coverage is comparedwith 100-mv/mm curve derived fromFCC data.

Only simple examples have beenshown. The pattern shaping is notnecessarily restricted to a null or sidelobe. The computer program is quiteversatile and the synthesis techniquehas been especially successful sincethe designer is in the decision makingloop.

Further work

One of the major problems in antennaarrays is pattern stability across thechannel bandwidth. The problem ismore severe in the case of multiplexedantennas. Simplified feed -system com-pensation is not economical. In suchcases, the compensation for phasechanges in the feed system has to beaccounted for. Work has been doneon the optimization of antenna illumi-nation taking into account the feedsystem of the array?' Another prob-lem is to determine whether any par -

09

0.6

0.7

cc 0.6

W 0.5;7.

0.4

.,cc 03

0.2

0.1

3

EORISRACTD ARRAYSPACING 60 IFAVEI noun

PANEL

NO

2

4

5

AMPLITUDE

0 9390.9411.0590.9351.227

PHASE

IDEGKESI

-39.610.4

-10.14.3

-5.60.63 -57.5

I 2 3 4 5 6 ? 0 9 10 II

DEGREES FROM HORIZONTAL

Fig. 7 -Array with power divis on underphasing.

ticular solution of the antenna arraysynthesis is the optimal one or whethera higher gain could still be obtained.An extension of the earlier work isunderway.

References

1. "Woodward, P. M..' A method For calculat-ing the field over a plane aperture requiredto produce a given polar diagram" IIEEVol. 93 pt lIlA (1946) pp. 1554-1558.

2. Hill. P. C. 1., "Methods for shaping verticalpatterns of VHF and UHF transmitting aeri-als." Proc. IEEE. Vol. 116. No. 8. (Aug.1969) pp. 1325-1337.

3. DeVito. G., "Considerations on antennaswith no null radiation pattern and pre -estab-lished maximum -minimum shifts in the ver-

0 9.

08'

02.

01

I0

09

06

07

X 06

,Thj 0S

0A

LLIIX 0

02

E0u1SPACED ARRAY

SPACING 6.0 WAVELENGTHS

PANEL AMPLITuDE PHASENO KGREES1

0.782 -39 22 0.952 7.4

0.967 -941.027 8,01.169 - 8 20.696 -34 2

01

*IOW I 4E105" I I I 1_,i0 n

03 2 I 0 123456769

DEGREES FROM HORIZONTAL

Fig. 8 -Array with power division underphasing, improved.

tical plane." Alta Frequenza, Vol. XXXVIII,No. 6 (1969).

4. Perini, 1. and ldeslis. M. H.. "Radiationpattern synthesis for broadcast antennas",IEEE Trans. on Broadcasting Vol. BC -18,No. 3 (Sept. 1972) p. 53.

5. Kraus, I. D., Antennas (McGraw-Hill BookCo.: 1950) pp. 521-534.

6. FCC Rules and Regulations, para. 3.699,Fig. 9.

7. Siukola, M. S. and Clark, R. N., "Variousmethods of determining the gain of a pro-posed TV Antenna", RCA Engineer, Vol. 16.No. 1.

8. Gihring, R. E. "Latest trends in TV broad-cast antennas" RCA Broadcast News Vol.105, (Sept. 1959) pp. 56-65.

9. Hill. P. C. 1. "A method for synthesizing acosecant radiation pattern by phase and vari-ation of a constant amplitude equispacedarray", in Electromagnetic wave theory"(Pergamon; 1967), pp. 815-850.

10. Crane, R. L., et al, RCA Laboratories,Princeton, N. J. Private correspondence.

TYPICAL VERTICAL PATTERNHIGH GAIN ZEE PANEL ANTENNA

IPU -60GAIN ) 60(HP ( 5 MEGAWATTSBEAN TILT 3/4.

NOTE THE 10011v /MUIR CURVE IS CALCULATED FROMPUBLiSHED FCC 50250 CURVES. II IS SHOWNONLY FOR THE PURPOSE 07 ILLUSTRATiON ANDSHOULD NOT BE CONSTRUED AS INDICATINGACTUAL COVERAGE TO BE EXPECTED

00 My(m AT 150011 HT

4 5 6 1 8

DEGREES FROM HORIZONTAL

Fig. 9 -Typical antenna patterns.

10

14

Television receivingantennas in blue and goldJ. D. Callaghan) D. W. Peterson

The profitable television receiving antenna product -line. being designed and produced byRCA Parts and Accessories. demonstrates the success that can be obtained by entre-preneurship within divisional boundaries of a large corporation. The necessary elementsof such success are the recognition of a viable market. the ability to reach it. and the talentto produce product at a competitive cost. Add a management team with the wisdom andforesight to identify and exploit these elements and the courage to make the necessaryinvestment and the result is a new area of pof it where none I -ad previously existed. Thispaper describes the engineering effort behind the development of the current RCAproduct line of "blue and gold" TV rece vino antennas and how its success has paved theway for the introduction of other product lines into market areas previously untouched byRCA.

R LA PIONEERED in the design andsale of television receiving antennas.However, the antenna business was onlyan adjunct to the home instrumentbusiness and, as such, was isolated fromthe mainstream of television receiverdesign and manufacture. Consequently.RCA was an early dropout.

In 1966. the RCA Parts and AccessoriesDivision at Deptford, New Jersey. re-entered the receiving antenna businessand, in 1970. introduced a new line ofRCA -designed antennas: this new linehas proven to be an outstanding success.The "Permacolor" antenna line illustrateshow RCA may profitably enter well -es-tablished small markets.

The television receiving antenna industryproduces a national aggregate gross in-come of about $50 -million annually andis dominated by several relatively smallmanufacturers who have been in ex-istence from the early days of TV. Formost of the major manufacturers, anten-nas represent a substantial proportion oftheir total business. This means that theymust organize their manufacturing alongquite simple and efficient lines to maketheir product highly cost competitive. Tore-enter this business, RCA had to im-plement an effective plan which wouldentail full control of engineering,manufacturing, and marketing-a planthat would equal or exceed the efficiencyof major competitors.

This was accomplished through severalphases. The first phase involved specify-ing and procuring a line of antennas from

Final manuscript received November 29. 1972

15

a competitor for exclusive sale by RCA.There are many drawbacks to buyingfrom a competitor; but there was no otherpractical way since, at the outset, it hadbeen decided that marketing,engineering, and manufacturingorganizations were to be established on apay as -as -you -go basis utilizing profitsfrom antenna sales. There are several ma-jor drawbacks to this approach:

I) A necessary economy in marketing antennasis the drop shipping of finished goods fromfactory to distributor. Thus, the competitorknows at all times who the RCA customersare; he knows their level of purchases; andcan approach the more attractive accountson the sale of their own "original" brand.

2)The antennas are easily recognized in themarketplace as the competitor's product, adecided product identity disadvantage.

3) RCA, as an intermediary betweenmanufacturer. and distributor, must markup the cost whereas a merchandisingmanufacturer can sell directly todistributors without this additional markup. This cost disadvantage is probably themost serious drawback.

Nevertheless, Parts & Accessories es-tablished an aggressive marketingorganization which has been able to buildsales to an attractive level.

Once the ability to achieve a significantshare of this market was established, thenext step was to develop a highly dis-tinctive line of antennas that could beproduced by a non-competitive manufac-turing source or by an RCA productionfacility. To accomplish this next phase,additional engineering and support per-sonnel were hired and an engineeringfacility was designed and constructed.

Antenna development facility

antenna development and design re-quires a special facility which must in-clude outdoor antenna testing ranges.Such a facility was planned and built atDeptford, N.J., in 1968. Radio -wavereflections from an adjacent building canseriously limit the capabilities of anantenna range, so the antenna buildingwas designed to minimize these reflec-tions. Since television broadcasting em-ploys horizontally polarized radiation,transverse horizontal wiring and plumb-ing in the building was avoided. Radio -frequency measurements of buildingmaterials were made as the basis forchoosing non-reflecting materials. Thesidewalls of the frame structure made useof vinyl siding with Celotex sheathingand interior walls, materials with far

Fig. 1 -Antenna development facility atDeptford. The curved radio -transparentwall used for "indoor" testing of antennasis at this end of the building.

lower reflection coefficients than mostbuilding materials. The roof material wascorrugated fiberglass sheet. The net resultwas a building unusually free of radio -wave reflections.

Special laboratory accommodationswere incorporated in the design of thebuilding to enable antenna developmentand design work to be carried on indoorsdespite inclement weather which oftenhinders antenna work on a conventionaloutdoor range. This "indoor" laboratoryis a room 20 ft high by 30 ft wide by 20 ft

Donald W. Peterson, Mgr., Product DevelopmentEng ineering. RCA Parts and Accessories. Deptford. N.J..joined RCA as an engineering trainee in 1936 and startedin the radio receiver Service Department in 1937 as atechnical writer. He transferred to the RCA ResearchLaboratories in Camden. N.J. in 1940. where hisactivities included development and research inantennas and radio wave propagation. As a member ofthe original technical staff of the Priceton Laboratories.he received a laboratory award and the IRE Scott Heltaward for the development of time domain reflectometryfor television transmitting antenna testing. He alsoreceived a laboratory award for concepts in UHF broa-dcasting. In 1961 he transferred to the Missile andSurface Radar Division as an antenna development anddesign engineer. Projects included development of acircularly polarized feed for the lunar excursion erectab-le TV antenna. He received a citation for work on the twopound radar antenna. In 1967 Mr. Peterson joined Partsand Accessories where he was responsible for thedevelopment of the RCA line of TV receiving antennas.

J. D. Callaghan, Mgr., Engineering, RCA Parts andAccessories. Deptford. N.J.. was employed by RCA in1946 as a member of the RCA Service Company HomeInstruments Engineering Department. His responsibi-lities included the development and approval of TVreceiving antennas and antenna systems. He alsoengaged in the development of color TV test equipment,TV technician training and liaison between the TVservice activity and Consumer Electronics Engineering.In addition, he received the RCA Award of Merit in 1951.In 1959 he joined the RCA Service Company BMEWSproject where he became Engineering Manager withresponsibility for on -site installation check-out and testof all BMEWS equipment. Mr Callaghan came to RCAParts and Accessories in 1964 and organized the presentEngineering group which develops accessory productssuch as TV antennas, rotators, signal distributionsystems, color TV test jigs. and automobile stereo tapeplayers. During the course of his employment with RCA,Mr Callaghan has been granted nine U. S. patents.

Fig. 2 -This end of the antennadevelopment facility shows the tower atone end of the radiation -patternmeasurement range.

deep. It is situated at one end of the build-ing and has a 20x30 -ft radio -transparentwindow in one wall facing an outdoorradiating source. The window wasdesigned -in house"and is considered uni-que. It consists of dacron-reinforced vinylsheeting stretched across a sturdy woodframe. The vinyl sheet is edge supportedwith heavy elastic ties to produce anatural tautness. The top and bottomedges curve outward while the side edgescurve inward. The resulting compoundcurvature imparts stability to the sheet,even in high winds (see Appendix A).After four years of service, the radio win-dow shows no deterioration. An outsideview of this radio -transparent wall isshown in Fig. I.

The indoor test room is ideal for gain andVSWR measurements. The room is partof a 100 -ft antenna test range and is usedfor gain measurement at all TV frequen-cies. An x -y plotter makes it possible to

Authors Peterson (left) and Callaghan.

16

plot antenna gain over the entire TV spec-trum automatically in minutes.Equipment is also available in the roomfor automatically plotting VSWRmeasurements vs. frequency. The entirenew RCA "Permacolor" outdoor line ofantennas was developed and initial testswere performed in this room.

The opposite end of the antenna buildinghouses the operating terminal of a 250 -ftantenna test range set up primarily forradiation pattern measurement. Thetower for the range is shown in Fig. 2.This tower can be lowered onto the build-ing deck by remote control for access tothe antenna mount. The range is

instrumented with a polar pattern plotterwhich operates with a bandwidth of only5 Hz to eliminate extraneousinterference.

The antenna under test is operated as asignal source. The range receivingantenna may thus be situated at theremote end of the Range where its direc-tional characteristics are used forminimizing local TV station interferenceto the extent that patterns may bemeasured between picture and sound car-rier frequencies of the local IN stations ifdesired.

Product development and design

Having planned and built the antennafacility, the first activity was developmentof a complete line of outdoor TV receiv-ing antennas. This meant that new elec-trical and mechanical design conceptswere needed in an art which had beenthoroughly worked over for many yearsby experienced competitors.

It was clear at the outset that the newRCA line would. of necessity. he elec-trically similar to competitive lines. Allcompetitors were using an end fire arrayfor the V H F portion of the antenna with a54 -to -till -MHz and a I 74 -to -216-M Hz

hand. Fortunately, most of the basic elec-trical design ideas came from early RCAwork on HF antennas. Common arrayelements for the low VHF and high VHFhands were obviously desirable foreconomy. This required creativeness and.similarly, the means of incorporating aUHF antenna for an all -channel line re-quired new concepts.

Existing competitive antenna designswere examined early in the program to

Fig. 3 - Antenna unfolding and interlock- Fig. 4 - Model 4BG36 "Permacolor"ing apparatus. antenna.

assess both their weaknesses and theirstrengths. A significant weakness thatwas common to all of the popular existingdesigns was soon discovered. In each ofthese designs. the antennas are packagedin a folded condition to facilitate storageand shipment. This requires them to beunfolded by the installing technician. Inthe usual design, each dipole element isfolded by use of a rivet acting as a hingepin. The contradiction in concept of set-ting the rivet loose enough for hingingand at the same time tight enough forreliable electrical conduction makes italmost inevitable that RF noise willdevelop when weathering causes cor-rosion at the hinge joint. Here was an op-portunity for design improvement. Anelectrical design was developed whichseparated the hinge function from theelectrical connecting function. This madeit possible to accomplish a permanentelectrical connection that is immune toatmospheric deterioration. The strapwhich permanently connects the dipole tothe transmission line is solidly riveted andis shown in Fig. 3. Permanent electricalconnection is further assured by the use ofspecial.fluted aluminum rivets which cutinto the sides of the holes in the materialbeing riveted.

A new feature was to overlap the dipolesat their insulating support. This overlapprovided an easy means of transmissionline transposition by simply reversing theoverlap on successive dipoles. In the finalproduct, the two halves of the insulatorwere designed to unfold and interlock asshown in Fig. 3, thus providing anoise -free dipole supporting structure ofgreat strength.' The overlap alsoprovided a new means for separating low -V H F and high -VHF antenna functions.The shunt capacity needed to accomplishseparation was provided inexpensively bymerely lengthening the element overlap atthe appropriate place in the array.

Another electrical feature introduced inthe design provided for a novel means ofplacing low -VHF directors in front of thehigh -VHF antenna without degradinghigh -VHF performance. This feature wasaccomplished by the bugle -shapedmembers seen as part of model 4BG36 ofthe"Permacolor" line illustrated in Fig. 4.The UHF antenna was incorporated intothe total configuration by placing acorner reflector type of antenna in frontof the VHF antenna and tuning the reflec-tor members to act as directors for thehigh VHF band'

Of economic necessity. the antennas arefabricated using the same kinds of partsand material as the competitors use: sheetmetal stampings. butt -seam tubing,welded tubing, and plastic moldings.These are all parts that can be fabricatedwith high-speed automatic machines tomake them cost competitive. A kit ofabout 75 common parts was designed forthis project. From this kit, all of theantennas needed fora complete line of sixVHF, three UHF, one FM and nine all -channel antennas could be made. Thereare also seven of these models packagedcomplete with all installation materialand several types of transmission line forthe do-it-yourself market.

Colors for the new antenna line,predominately blue with gold supportbooms, were adopted by merchandisingto add "eye appeal." The color choice alsorepresented innovation since all -goldfinish had become standard with the in-dustry.

Even the package size of the product is asignificant cost factor because warehous-ing and shipping represent cost just assurely as do materials and labor. Theantenna was, therefore, designed to be theultimate in compactness when folded. All

17

but four antennas of the I9 -antennaproduct line are packaged in standardlong, slender cartons that are only 51/4 in-ches square. Despite their folded com-pactness, the antennas unfold with easeand lock positively and permanently intotheir functioning configuration.

The antennas are marketed by the Partsand Accessories Division located atDeptford, N.J. The salesmen reach RCAConsumer Electronics distributors, aswell as many other independent outletsthroughout the entire nation. Salesvolume has grown to the point wheresingle distributors often order tractortrailer -size deliveries.

The advertising of this product has beenboth straightforward and effective. Theforthright character of the RCA adver-tising makes it stand out in an industrywhich has often grossly exaggerated intheir advertising copy.

The RCA product has strong and easilyrecognized sales features which give boththe Advertising Department and thesalesmen a story for their customers.

All of the RCA antenna laboratoryproducts and components are fullydocumented within the RCA drawingsystem. The general excellence of thissystem has permitted both precision andflexibility in dealing with vendors as wellas tight control of the product in theantenna factory.

Antenna factory

Most of the metal parts used in produc-tion are fabricated "in-house". The fac-tory employs high-speed stampingmachines, rolling mills, piercingmachines, swaging machines, and othersimilar equipment. All aluminum sheetmetal is pre -finished before stamping,rolling, or piercing. Even welded tubing,which is purchased, is finished beforeforming and welding. A tube -bendingmachine is shown in Fig. 5. Stampedparts are produced with automaticmachines at a high rate with progressivedies. Plastic parts are produced fromRCA molds by suppliers who specializein these items.

Antennas are assembled withautomatically fed riveters along a 200 ftmoving belt as shown in Fig. 6. Quality isassured by inspection of vendor -supplied

parts, and by assembly line inspection.Antenna quality has remained high fromthe start of production.

Entrepeneurship-Parts and Acces-sories style

As a business enterprise. RCAengineering, manufacturing, and market-ing of antennas is an unqualified success.The product is good, the price is right, thecustomers are pleased, and RCA shows arespectable profit. The entire under-taking has been carefully tailored to fitthe product with no room for frills. Everymember of the team plays a vital role andevery member knows how he relates tothe overall effort. Morale is high amongthe participants because everyone seestangible results from his individual ef-forts. Business success becomes personalsuccess.

The antenna activity is integrated as partof RCA Parts and Accessories.Marketing, Advertising. Sales, Ac-counting, Purchasing, and Engineeringactivities are located in Deptford, N.J.The sales organization operatesthroughout the entire United States.

The RCA investment in a salesorganization, an engineering facility, thedesign effort, tooling, and the manufac-turing facility, along with successfulproduction and promotion. has con-vinced even the most skeptical that RCAis in this business to stay.

RCA's superior position in marketinghome instruments has, of course, helpedin marketing RCA antennas. The RCAname and reputation have been ofsignificant value in opening customerdoors for this new product line. Forgrowth to continue at a healthy rate,however, it has been necessary that theantenna line measure up to the name.Along with the relationship to the Cor-

Fig. 5 - Tube -bending machine.

poration, at large, the new antenna ac-tivity has been able to create its own wayof life-a way that is highly efficient in theproduction and sales of a product in anestablished and competitive market.

After successfully launching themanufacture of the "Permacolor" out-door line of antennas in the RCA antennafactory, other products were examinedfor possible addition. Similarly, a highlydistinctive line of indoor antennas wasalso developed; these antennas are nowproduced in our manufacturing facility.In both cases, the advantages of in-housemanufacture proved to be a substantialfactor in achieving planned businessresults.

The future

The RCA antenna laboratory building atDeptford also provides for an engineer-ing activity engaged in investigating avariety of other potential products. Thereis a complete model shop. a design anddrafting room, and general engineeringlaboratories.

Other product items that have beendeveloped by P. & A. Engineering includea TV -antenna -system accessories line of45 items. These consist of amplifiers andpassive devices required for small hometype M ATV. (master -antenna TV)systems, a few of which are shown in Fig.7. There is an antenna rotator line withthree models, plus a complete line ofantenna -installation hardware. RCAParts and Accessories also engages inother diversified product design. One ofthese is car stereo tape players, someitems of which are shown in Fig. 8. TheRCA engineering contribution to thedesign of these products varies from com-plete product design to critical review andmodification. Careful factory productioncontrol is exercised on all product lines. It

Fig. 6 - Automated riveting operation.

18

Fig. 7 -Some of the accessories -line formaster -antenna TV systems.

is expected that some of these productswill eventually go the full way from out-side procurement to RCA manufacturealong the same lines patterned by theantenna business.

The Deptford engineering group hasalready had substantial experience withantenna rotator and RF amplifier design.There has also been an advanceddevelopment project in cooperation with

(a)

TIE POINTS ALONGEDGES OF SHEET

(0)

Fig. 9 - Sketches of radio transparentwindow.

Fig. 8-Some of the car stereo -tape line.

the David Sarnoff Research Center.' Thishas resulted in the creation of a newconcept of a miniature transistorized,rotatable, outdoor antennas which is en-closed in a weatherproof housing. Thisproduct will he introduced early in 1973.The development of this antenna will befully described in a future issue of theRCA Engineer.

Acknowledgments

Neil Burwell and Frank Di Meo were res-ponsible for the mechanical design and

the product design of the "Permacolor"antenna line. Mr. Burwell died shortlyalter conclusion of the mechanical designphase of the antenna line.

References

I I )1Nleit. . R. and Burwell. N. W. (13('Nt. Collapsiblestructure bs.support antenna element. U.S. Patent 3263.117I Nos.. 14711.

'.Peterson. I). W. (RCA). Combined 1 Iff-1 HF dipole0,1111. U. S. Patent 3.653.056.

1,111;111h:tn. .1. I). IRCAI. r antenna. U.S.Patent 3.6)0.391.

I I he new antenna concept was developed at Ikptlord underthe leadership of 1)r. James Gibson 01 the Ilavid Sarno')Research renter.

Appendix A-Design of the radio -transparent window for the antennadevelopment facility at Deptford, N.J.

The radio -transparent window consistsof an edge-suported, single plastic sheet600 IC in area. A sheet of this size will beexposed to approximately 14,000 lbs ofair pressure in a 90 mi/ h wind. It is notdifficult to design a wood structure forthe static load that this imparts to the sup-porting frame. However, if such a sheet isdrawn taut to a flat surface, it tends to os-cillate in the wind. It is the oscillationwhich makes the sheet self-destructiveand adds substantially to the stresses im-parted to the support members.

A method for minimizing wind -inducedoscillation was conveived by NeilBurwell. If ABCD of Fig. 9a representsthe open end of a box, a vertical string at-tached to top and bottom can be renderedincapable of oscillation in its fun-damental mode by pulling it toward theinside of the box at point 0 at the center.A second string stretched horizontally ac-ross the opening can be similarlyrendered non -oscillating by pulling itscenter outward from the box. If the ends

of the horizontal string are movedinward, EOF and GOH become a stablesystem with neither string capable of fun-damental -mode oscillation. A similarbalance of forces may be accomplished ina sheet attached to points ABCD by cur-ving the top and bottom outward and thesides inward as shown in Fig. 9b.

I he outside wall of the antennalaboratory is such a compound curvedsheet, made of polyvinyl chloride rein-forced with a dacron fibers. The sheetconstitutes the entire end wall of thebuilding shown in Fig. I. It was drawntaut and permitted to be self -equalizingby use of heavy elastic ties along theedges.

Prior to the erection of the full-scale wall,a scale model of the plastic sheet and theelastic supports was constructed over avacuum chamber. The behavior to be ex-pected in high winds was studied by par-tially evacuating the chamber andmeasuring tension in the elastic ties.

19

G&CS antenna rangeW. C. Wilkinson

The antenna is a major element in most of the systems produced by the variousdivisions of G&CS. The development and measurement of these antennas requiresincreasingly sophisticated facilities and controlled conditions. A new RCA antennatest range for this work has been planned and is being implemented. Special attentionhas been paid to the problems of mutual and external interference from systems bothin operation and under test. Management as well as technical design will play animportant role in the solution of these everpresent problems.

SINCE THE COMPANY was formedmore than 50 years ago, RCA has

had a major role in antenna research,design, and manufacture. One of theearliest was the Beverage' or wave an-tenna consisting of two horizontalwires 9 miles long. One of the latest isthe AN/SPY-1 antenna: consisting of4480 electronically steered elements.The types, sizes, and frequencies havebeen as varied and as extreme as theelectronic communications art itself.

A necessary adjunct to any antennadevelopment is a test or measurementcapability. In RCA, these measure-ment facilities have taken many forms

Final manuscript received October 25. 1972

William C. Wilkinson, Ldr.Space and Airborne AntennasRadiation Equipment EngineeringMissile and Surface Radar DivisionMoorestown. N.J.graduated from Purdue University in 1941, withthe BSEE. Since then, he has been employed byRCA; in 1941-1942. at the Manufacturing CoCamden, N. J.; in 1942-1961 at the RCA Labora-tories, Princeton, N.J.; and since March 1961 atthe Missile and Surface Radar Division. Moores-town, N.J. His experience has been in appliedresearch and advanced systems development. RFtransmission and components, and in antennas.Particular areas of experience are: narrow -beamrapid -scanning antennas at microwave and milli-meter waves, airborne high -resolution radar: andground -space communication antennas. At pres-ent, he is engaged in developmental programs onantenna systems. Mr. Wilkinson is a member ofSigma Ki, Eta Kappa Nu. and a Senior Member ofthe IRE.

20

in numerous locations: building roofs,vacant lots, unused baseball fields,specially designed buildings, and elab-orately graded terrain. In the past(and to some extent even at present),the test locations and facilities repre-sented the narrow needs of a singledivision or product line. Althoughsuch parochialism limited the re-sources that could be used for capitalequipment, a competitive positioncould generally be maintained.

However, the great strides made inelectronics during and since the WorldWar II, and the pressing requirementsfor communication by the world's in-creasing population have enormouslyincreased the complexity and neces-sary capability of antennas. In addi-tion, labor costs and schedule needsmake high -data -rate test equipmentmandatory. The result is that testfacilities have increased manyfold insophistication and cost. Hand -turnedpositioners and point -by -point hand -

plotted data points exist only in thereminiscences of not -so -old engineers.

History

Somewhat over ten years ago, thedefense group of RCA divisions con-solidated the antenna personnel atMoorestown in the Missile and Sur-face Radar Division for the purposeof enhancing the development and de-sign capability. The commonality ofantenna experience would improveand cross -feed designs for the variousdivisions; the DEP Antenna SkillCenter came into being. In the yearssince its formation, the grouped an-tenna skills have served all five divi-sions in many programs, and havecontributed materially to the needsof the commercial divisions. (An an-tenna range is operated by CSD at

Gibbsboro, N.J. for development andproduction test of FM and TV broad-cast transmission antennas.' Anotherrange for TV receiver antennas is op-erated at Deptford.'

At about the same time that the An-tenna Skill Center was instituted, therange facilities at Moorestown wereseriously affected by operation of theprototype of the BMEWS tracker, theAN/FPS-49, a nearby very highpower radar. A number of the an-tenna test programs were moved tothe just previously relinquished HomeInstruments receiver test site at Med-ford, NJ., approximately nine milesfrom the M&SR plant. This small sitehas been in continuous use since, forprograms which could not tolerate theambient electrical noise level atMoorestown. However, the site wasonly an expedient and never becamea complete permanent range.

The need for a consolidated perma-nent range has been recognized, butthe apparent requirement for moresuitable land became a stumblingblock. As noted, the pressing needsfor better facilities triggered an eval-uation of previous range plans in lightof existing constraints. The difficultiesof obtaining land located sufficientlyclose and situated such that it wouldbe in a noise -free enivronment forthe reasonable future, forced a re-examination of the potential useful-ness of the Moorestown property it-self. Two conclusions were reached:

1) This property could be used if afull program of noise control werecarried out; and

2) No other location would be mark-edly better.

The particular and general rangeneeds were assessed and a master plandeveloped for an orderly implemen-

tation over a 4- to 5 -year period. Thisplan has been approved, and periodicreviews and assessments will modifythe plan details, if necessary, as timegoes on.

Requirements

As noted, the types and sizes of an-tennas developed at MSRD havespread over a large span. It is ex-pected that this will continue. Thus abroad general capability must be met,recognizing of course that there willalways be sizes and types so extremethat special techniques and facilitieswill be required. The general require-ments for a range site are:Size adequate for developmental

testsInterference minimal or within controlAccuracy permanent calibrated rangesSupport shop, laboratory,

housekeepingLocation convenient to the MSRD

main plantAll-weather sufficient to maintain

schedules

Fig. 1 shows the relationship of mini-mum required range length, antennasize, and frequency. Various represen-tative antenna developments are spot-ted, illustrating that most of the pro-grams can be satisfied with a rangelength of 3000 to 4000 ft.

Interference is of two kinds, passiveand active. Passive relates to those ef-fects which prevent the antenna frombeing tested in a free -space environ-ment: multi -path or unwanted scatter-ing effects of ground reflections,buildings, and natural vegetation. Ac-tive interference includes all unde-sired radiation.

The ever-present ground is handledby either of two techniques:5 the test

ANTENNALABORATORYBUR.VNG

MAINPLANT

MSRO MOORESTOWN

112 ACRES

'COO

antenna and source are elevated tominimize ground reflections, or thetwo end points are located close to theground and the ground reflection con-trolled and used. The former is calledan elevated range and the latter aground -level range. In some instancesadvantage has been taken of two ele-vated points separated by a valley.South lersey, unfortunately, does notboast such features. More generallyone or both terminals are placed ontowers and residual spectral groundreflections broken up or absorbed tosome tolerable level. This is a type ofrange employed at MSRD for manyprograms.

The ground -level range requires care-fully graded and controlled terrainbetween the test antenna and thesource antenna to maintain a stableaddition of the ground -reflection sig-nal with the direct -link signal over thearea of the test antenna aperture. Thistype of range is useful for certainsizes and frequencies.

Active interference is generated bymany sources: some are licensedtransmitters, others are incidentalnoise generators. The ever-increasingnumber of radar and communicationstations puts almost any test site inan interference area. In addition,MSRD itself has a continuing numberof radar and high -power transmittersunder test. Source radiation of multi-ple ranges themselves may cause intra-range problems. Tolerable levels canbe reached and maintained only by anacross-the-board attack:

1) Elimination or reduction of the in-terference

2) Discrimination against the inter-ference

RANGES

- - -DEVELOPMENT- SYSTEM

PACETRACK

0*NNW RANK LIMIT. FOR PATTERN IMATAIMITRITS

0

.1:

S.

O

O

co 1.000 ANGE 41,riorm

a* E GO*

ANTENNA SIZE -FEET

FT

I .0

Fig. 1-Relationship of minimum range length,antenna size, and frequency.

The first works on the interferencesource, the second on the test antennareceiver.

Range planGeneral

The general plan consists of fourelements:

1) Location and layout2) Building modifications3) Interference control4) Facilities and equipment

The major location of the range andits parts will be on the RCA Moores-town property, a triangular -shaped400 -acre piece of land (Fig. 2). Thenucleus or hub of the range will be anexisting building (Fig. 3); this can beused with only minor interior modifi-cations. The interference control willextend to all phases, from preventionof interference generation to the op-

Flg. 2-Radar test ranges, MSRD. Fig. 3-Antenna laboratory buildirg.

eration in interference using sophisti-cated discrimination equipment. It in-cludes technical management as wellas techniques. The facilities andequipment consist of anechoic rooms,source towers, test equipment, sur-veyed and calibrated test ranges, andthe accessory shop, laboratory, andcomputer support.

Location

The antenna laboratory building (Fig.3) is located about 1/2 mile north ofthe main plant buildings and is sur-rounded by more -or -less open fields.It formerly housed the equipmentused for outdoor backscatter and sig-nature analysis measurements. Afterlying almost idle for some years, itwas recently put into service for theAN/SPY-1 antenna measurements.This latter equipment and its arrange-ments, a major capital investment it-self, will be incorporated into theoverall range plans. Fig. 2 shows therelationship of the building to theproperty.

All but one of the ranges will havetheir terminus here. A short range istentatively planned to be located onthe existing RCA Gibbsboro site.'This is about 14 miles, or 18 to 20minutes, from Moorestown. The needand use for this range will depend onparticular interference problems atMoorestown. Plans also include theuse, if needed, of a small piece of landsuitable for a source tower located atArney's Mount, about 13 miles north-east of Moorestown. Activity at theleased Medford test site is to bephased out and terminated_

The plan includes renovation of theantenna laboratory building and somemodifications. The basic building lay-out and major supporting walls fitinto the range needs quite well. Fig. 4shows the layout and planned use ofthe building interior.

Interference control

The interference control plan includesthose areas of activity which will per-mit antenna measurements to bemade throughout the Moorestownranges with a minimum of interfer-ence. It is clear that there is no singlesolution, that there will be some pe-riods of unavoidable conflict, and thatthe problems will require continualattention and periodic activity. On the

other hand, there is probably no loca-ation which is either completely freeor could be sheltered from similarkinds of interference for any long pe-riod of time.

The interference control consists oftwo kinds of activity: technical inves-tigation and control, and range man-agement and control. The first hasthese steps:

Interference measurement andanalysis

Development of techniques fordiscrimination

Construction or modification of testequipment

Existing and potential interferencesources have been defined by measure-ments and by tabulation of licensedtransmitters. This data will be usedto influence location and orientationof ranges as well as allocation of in-dividual ranges to programs. It willpinpoint excessive levels and identifythose which can be reduced.

Range management will include theestablishment of a Range ControlBoard which will guide and control:

all planned range use all range modifications all MSRD land use all range capital equipment

By these means, potentially seriousconflicts can be averted, planned timesharing can be influenced, major inter-ference sources can be prevented, andundesirable interacting activity can beminimized. This board will seek tooptimize solutions for short-termproblems while maintaining the longterm integrity of the range capabilityand capital investment.

Radar -type Interference

One particularly troublesome type ofinterference is that from nearby ra-dars, both operational and experimen-tal or in test. These are located bothoff and on RCA property and natu-rally tend to be in the same generalfrequency bands as antennas to be de-veloped. While frequency discrimina-tion and modulation coding can domuch, it cannot handle all situations.The pulse nature of the interferencesuggests that a blanking technique canhave value. The low duty cycle ofmost antenna measurements willallow, in effect, time sharing of thesame spectrum.

An experimental evaluation and

equipment development for this tech-nique is underway and initial resultsare quite promising. Synchronizationwith the interference pulse is obtainedfrom the leading edge for equipmentsoff -property and beyond control.Those on -property can be synchro-nized likewise, or, for extreme high-level problems and pulse -rate -agilesystems, hard -wired video or RF linkscan be used to completely blank thepulse. It is unlikely at a given fre-quency and situation, that more thanone to three interfering equipmentswill be operational simultaneously.Thus the potential reduction in meas-urement data rate does not appearsevere.

Description of ranges

The various existing and plannedranges are listed in Table I and theirlocations delineated in Figs. 2 and 5.Two important guidelines are beingused in their design and construction:

1) Ranges will have permanent cali-brated capabilities using dedicatedequipment; and

2) Operating equipment and procedureswill incorporate labor-saving andtime -saving features.

A major portion of the requiredequipment is already owned and ingeneral use. This will be rearrangedand supplemented. Ranges 1 and 2exist in part. Forms of ranges 5, 6,and 7 exist at other locations. Ranges3 and 4 are in process of being built.The remaining three will be imple-mented as their need becomes moreimminent.

All the ranges consist of the receivingend where the antenna under test isrotated through its various look an-gles, and the transmitting or sourceend from which a test signal is radi-ated. The receiving end will have apad and pedestal with a drive systemfor rotating the antenna, a receiver,and recording equipment for sensingand documenting variations in the an-tenna performance. The transmittingsource will generally be located on atower and will be remotely controlledin orientation, polarization, and fre-quency. The use of phone lines anddigital circuitry for control is planned.Some receiving sites will be enclosedfor all-weather operation and toallow tests on antennas with particu-lar environmental limitations, such as

22

CALLED

those for space. A capability down to200 MHz will be available in thesechambers.

Range No. 1 is already in existenceand in use. It was designed to test theAN/SPY-1 antenna-a high data -rate,wide -coverage, broad -band, electronicscanning antenna. This is a 900 -ft -longelevated range, operating between a150 -ft -source tower and a 50 -ft -hightower -mounted pedestal. The meas-urement and data requirements ofthis program dramatically illustratethe magnitude of modern antennatesting. This array has a 100 x 90°coverage with a less -than 2° beam. Foreach beam position, three monopulsepatterns must be assessed: one sumand two difference patterns, and theseat several frequencies. Gain, beam -width, lobe level, beam position, anderror slope are only some of the datathat must be gathered.

The pedestal and signal source as wellas the antenna beam steering are con-trolled by a programmed computer(Digital Equipment Corp., ModelPDP-11, with 18k core memory).Measured data is stored on magnetictapes for evaluation and reprocessingfor presentation. The computer alsoanalyzes and presents spot data in realtime to validate measurements beingtaken.

Ranges 3 and 4 are being built as apair, using a common control roomand source tower. Certain specializedrecording and control equipment willalso be shared. The two ranges havedifferent but over -lapping frequencyranges. Likewise Ranges 1 and 2 willshare a common control room andsome equipment.

ConclusionThe complement of ranges as pro-posed will give RCA an antenna de-velopment and measurement facilityfully suitable to the needs of the fore-seeable future. These will support theproduct lines (other than broadcast)of the other four G&CS divisions aswell as MSRD.

ReferencesI. Beverage, H H.. "The Wave Antenna" Trans.

of AIEE, Vol. 42 (1923).2. Scc AEGIS papers in RCA Engineer, Vol. 17.

No. 1 (Tune-fuly 1972).3. Gehring. H. E.. "The Broadcast Antenna Fac-

ulty" RCA Engineer, Vol. 8, No. 3 (1962).4. Callaghan, I. and Peterson. D., "Television

receiving antennas in blue and gold," thisissue.

MACHINE SHOP295 28

EQUIPMENT: 'ROOM i

I

- - - - \ I ANECHOIC CHAMBER

*BOILERROOM MEA

68'5 28'

UTILITIES AND ASSEMBLY5 5 28

BENCH TESTLABORATORY

18 %28

TESTEOIIPMENTSTORAGE135 20

ROOM

- - - -

I FEED:CHAMBER

COMPUTERAND DATAPROCESSOR

12 X 28

RECEPTIONAND

MEETING ROOM20518

ENTRY9 X 8

OFFICE103H

0I

5:.118

afWJ

TO 19ORTONLANDING ROAD

43 -

Fig. 4-Floor plan of antenna laboratory building.

Fig. 5-Configuration of antenna laboratory facility.

Table I-Developmental ranges.

5 -cf

No. TypeHeight (ft) Length MM. freg.

Transmit Receive (Fl) (MHz) Remarks

1 Elevated open 150150

2002 Elevated open 150

2003 Ground level and 0 to 40

elevated semi- 200anechoic

4 Ground level and 0 to 40elevated semi-ancchoic

5 Ancchoic room6 Shielded anechoic room -7 Ground plane 0 to 1508 Elevated range Various

9 Elevated

10 Line of sight

50 90050 250050 3700

24003700

26 0 to 300 100026 2400 1000

26 0 to 300 400*200 26 2400 400*

- 10 1000- 40 10000

75 Variable

25 25 0 to 100

300 50 70,000

Feed and element testsFeed and element testsHF scale model testsFor high front -to -back and main -to -minor lobe ratios.Located at Gibbsboro for specal in-terference problems.Potentially useful.

Useful to 200 MHz at some performance accuracy reduction.

23

24

INTERNATIONAL FIELD OFFICES EUROPE, MIDDLE EAST & AFRICA HOME ADDRESS

RCA International Marketing S. A.118 rue du Rhone

AUSTRALIA HOME ADDRFSS CH 1204 Geneva. SwitzerlandPhone 356260

RCA L muted Cable RCA CORP GENE VA11 Khartoum Road 22306North Hyde. N. S. W.Australia 2113 Dongelewicz, L. R. Manager. Sales Les Arrenny.ChataigneriazTelex RCA AUST AC790 21654 (Ray) Europe. Africa 1297 F °unix , VD. Switzerland

SYDNEY & Middle East Phone 76-15-27Phone 888-5444

Walsh. R. D. Manager,(Ray) CES Sales

4 Lyle AvenueLindlield. N. S. W.

Berben. P. C. L. Sales,(Peter) Africa

28, Chemin de la Gradelle1224 Chene-BougeriesGeneva, Switzerland

2070 Australia Phone 48-71-23Phone 465777

Boatman, J. M. Sales. Villa Les Gonthiers A.Schlie, Gerald Administrator,

Sales Support19 Stokes StreetLane Cove. N. S. W.

(John) C. Europe En Peny1295 Mies. V. D.

2066 Australia SwitzerlandPhone 55-39-93

Wilkinson. J. A. Sales Engr. 13 Lumeah Avenue(Jim) Elanora Heights. N. S. W Gibson. J. Sales. 28 Chemin de la Gradelle

2101. Australia (John) Africa Apt. 12Phone 913-7319 1224 Chen-Bougeries,

Geneva. SwitzerlandRCA Limited Phone 48-12-222-4 Stephenson StreetRichmond, Victoria3121 AustraliaPhone 424586Telex AA -31437

Gibbs, A. R.(Alan)

SOUTH AMERICA

RCA International Ltd.Calle Paroissien 3960Buenos Aires, Argentine

Sales Engineer 47 Reserve RoadBeaumaris. Victoria3193 AustraliaPhone Melbourne 99-1295

RCA LimitedLincoln Way, Windmill RoadSunbury-on.T harnesidliddlesex , England,:able"elex,hone.

Craddock. D. F.(Dave)

RCA LONDON24246Sunbury -on -Thames 8.5511

Sales E ngineer 180 Laleham RoadSheppertonMiddlesex, EnglandPhone Chertsey 65903

CablePhoneTelex

RCA AR - Buenos Aires704171121 -239 -AR RCA International Ltd.

RCA HouseMagma. H. T.

(Hector)Manager, SalesSouth America

Arribenos 1610-21,Buenos Ines. Argentina

50 Curzon StreetLondon. WI Y 8EU

Phone 734673 E ngland266579

E 'man, J. A. Sales. Urbanicacion Las Mercedes Phone 499-4100(Jose) South America Calle Madrid. Ou intatana

Zone Postal 107 Hogan, J. R. Director. Marketing 76 Kelvedon AvenueCaracas. Venezuela (Bud) Europe. Africa and Burwood ParkHome Phone 371398 Middle East Walton on -ThamesOff ice Phone 917886 Surrey. England

Phone 41422Stamen. 0. R. Sales.

(Oscar) South AmericaJose Hernandez 1775Piso 17

FICA Jersey LimitedRue des Pres Trading EstateL ongueville RoadSt. SaviourJersey Channel Island. EnglandR TA RCACI

Villanustre, A. J. Sales,(Adrian) South America

Lafuente 1119Aveilaneda

Phone CENTRAL 35355

Buenos Aires, Argentina Dare. P. A. Manager Apt. 4(Peter) B/C Systems 23 Havre dos PasRCA Telesistemas Ltda Product Mgmt. St. HelierRua Correa Dutra, 1264And

Rio de Janeiro - GBBrazil

Jersey ChannelIsland,Phone: East 2579

Cable BRA RCA - Rio de .aneiro Morin, P. J. Managing Director Douceville FarmPhone 245-9209 I Pat) Mont Cochon265-5107 St. HelierJersey. Channel IslandSchemer. L. Sales,

(Leonardo) South AmericaRua Figuelredo Magalhaes248 Apt. 504

EnglandPhone Central 22848

Rio de Janeiro - GB BrazilPhone. 236-3873 CANADA

RCA LIMITEDFAR EAST SALES 21001 North Service RoadTrans -Canada HighwayRCA International Ltd. Ste. Anne de Bellevue. 810

1927 Prince's Building Quebec. CanadaChafer Road Phone 1514/ 457.9000G. P. O. 112 R TA -RCAMONTHong Kong Telex: 05-821572Cable RCA CORP HONG KONG TWX. 810-422-3932Phone H 234181 DLC.724International Telex HX3645

Holroyd, W. H. Ext. 510/ Manager. B/C & Bei leview DriveF tonne,. G. B. Vice President 1939A Se Ngo Shon Road 511 Instr. Sys. RR 1. Como(George) Kowloon Hudson. Quebec. CanadaHong Kong Phone 514 I 236-72833 229229

Curtis, R. H. Ext. 511 Administrator 4383 Harvard Avenue(Ross) Montreal 262. Canada

Phone 514 481 0871Gilbeau, L. E. Ext. 511 Manager. Special 7405 Glenwood Ave.

(Leo) Accounts Town of Mount RoyalQuebec, CanadaFoody. P. J. Sales. F tat 16E. Far East Mansion Phone 514-739-5852(Paul) Far East Middle Road

Kowloon West, W. Ext. 511 Manager. Special 83 Burns StreetHong Kong Accounts Beacons SieldsPhone 662383 Quebec, Canada

Phone 514-6952535

TORONTO OFFICE:MEXICO. CENTRAL AMERICA & CARIBBEAN HOME ADDRESS

1450 Cast lel field Ave.RCA S. A. de C. V. Toronto 15. OntarioAv. Cuitlahuac No. 2519 CanadaApartado Postal 17-570 PP one (416) 651 6550mo'ic017 D.F.Cable: Radiotnter Mexico City Norton. R J. Manager, Central 337 Lawrence Ave. WestPhone: 5-27-60.20 (Bobl Canada Region Toronto 12, Ontario

CanadaPerez, C. P. Manager. Sales Av. Gloneta Norte No. 44 Phone 416789-5082

(Carlos) Central America TlalpanPhone 527-44-19 & Caribbean Mexico 22 D. G VANCOUVER OFFICE:Ext. 104 Phone 5-711403

2876 Rupert St. at Grandview Hwy.Guillot, Fernando Sales Convento San Jeronimo *4 V.incouver. British Columbia

(Fernando) Central America Santa Monica, Mexico CanadaExt. 142 397-0174 Phone 1604/433 0541

Harlow, R. L. Manager, Western 2133 Anita Drive(Dick) Region Port Coquitlam. B. C.

CanadaPhone 604-9426969

BROADCAST FIELD OFFICES

Departments identified below as follows B - BroadcastFR - Film RecordingG -CC - Government - Closed Circuit

Distance Location Code is provided where applicable. This number must be precededby the local CTN Direct Dial Access Code.

OFFICE NAME

RCA Building Tamer. C. F.14 Executive Park Drive. N. E. ICharlielAtlanta GA 30329 Ext. 240/241404634-6131 OLC 697DLC 697Telex - 54-9666

AUSTIN

Northwest Off ice Park Bldg.Suite *1348330 Burnet RoadAustin TX 78758512-451-2500 and 4538233TWX - 910874-1388(RCA BDCST AUSI

B IRMINGHAM

Off ice Park Building No. 10Off ice Park CircleBirmingham AL 35223205-871-1155

B OSTON Area

40 William StreetWellesley Office ParkWellesley MA 02181

97-237-6050BURBANK

2700 West 01. AvenueBurbank CA 91505213-849-6741DLC 353

CAMDEN

Front & Cooper Streets8100 2-2Camden NJ 08102609.9638000TO( EE8-365-5939

CHARLOTTE

6230 Fairview RoadSuite 104Charlotte NC 282107043660626

CHICAGO

Gateway II Bldg., Suite 1400120 South Riverside PlazaChicago IL 60606312.782.0700DLC 267TWX 910221.2455RCA BCST CGO

CINCINNATI

11430 Hamilton AvenueCincinnati OH 452315138251550

DALLAS

8700 Stemmons FreewayDallas TX 75247214-638-6200DLC 2694TWX 910-861-4260

Walters, P. G.(P. G.I

Ext. 243DLC 697

Forbes, D(Donl

Nobo, A.(Art)

Morse, J.(Jack)

Dickinson, R. S.(Bob)

Ext. 278

Hudak, N.(Nick)

Ext. PC.3592

Geydos, C. J.(Charlie)

Camden - Ext.PC -5275 & 2937

NYC - Ext.RR -8393 & 8394

DLC 034

Preston, J. L.(Jerry)

Ext. PC.3592

Tyrrell, R.(Dick)

Ext. PC 2020

Smith, J.(Jerry)

Bierka O. G.

Ext. 210

Gibbs, .(Phil/

Ext. 213

Tunberleke, F.(Tint)

Ext. 212

Raasch, C. E.(Carl)

Hoff, E. H.(Herb)

Ext. 233/232

DEPT. HOME ADDRESS

G -CC P. 0. Sox 49485Atlanta GA 30329404-938-6287

B 3263 Wynn DriveAvondale Estates GA300024042892175

B 7604 Silvercrest CircleAustin TX 78757512-4578392

B 3156 Old Columbiana RoadHoover (Birmingham) AL35226205-822-4415

B

FR

*7 Stagecoach RoadHingham MA 02043617-7492314

Hillside Apts. *302470 E. Angeleno AvenueBurbank CA 915012118436253

B 13 Colgate DriveCherry HA NJ 08034609667.3352

G.CC 143 Pearl Croft RoadCherry Hill NJ 08034609.429-1184

B 8 M Millside ManorDairen NJ 08075601461.2871

G.CC 280 Sawmill RoadCherry Hill NJ 08034609.428.2736

El 5037 E. Quail Hollow Rd.Charlotte NC 28210704-364-4720

GCC

B

B

B

6401 N. Sheridan Rd.Apt. *604Chicago IL 60626312-4653469

W28-530105Bethesda CircleWaukesha WI 53186414.968-2775

2002 N. Elizabeth Dr.Arlington Hgts IL60004312259-9774

9335 Renchill DriveCincinnati OH 45231513931.2125

2212 Sutton PlaceRichardson TX 75080214.235-5870

OFFICE

DALLAS

DENVER

2701 Alcott StreetSuite 384Denver CO 80211303-433-8484TWX 9109312624

DETROIT Ares

NAME

McClanathan, G(George)

Ext 234/232

Penske, L.(Lee)

Eat 204/205

Butts. J. H.LAM

24333 Southfield Road Happel, W.Suite 209 (Warren)Southfield MI 48075DLC: 95 Extension 248HOLLYWOOD

Suite 5316363 Sunset Blvd.Hollywood CA 90028213-461-9171DLC 38TWX 910.321-4089

JACKSONVILLE

2747 Art Museum DriveSuite 5Jacksonville F L 32207904-398-4588

KANSAS CITY Area

5750 West 95th StreetSuite IIIOverland Park KS 66207913642.3185,6, 7TWX 910749 6484DLC 272

MEADOW LANDS Area

716 N. Washington RoadNationwide Off ice Bldg.McMurray PA 15317412-941.5570CTN 784

MINNEAPOLIS

4522 Excelsior Blvd.Minneapolis MN 55416612-9206385 or612-920-6396

NEW YORK

5th Floor1133 Ave. of the AmericasNew York NY 10036212.598.5900DLC 034

SAN FRANCISCO

420 Taylor StreetSuite 401.408San Francisco CA 94102415-441-2200DLC 7337.102

ST. LOUIS

7701 Forsyth Blvd.Suite 455St. Louis MO 63105314-862-3660DLC 278

SEATTLE

408 Second Ave., W.Seattle WA 98119206285-2375

WASHINGTON, DC Area

1901 N. Moore StreetArlington VA 22209703558-4233DLC 754Twx 710955-0662

703558-4212

1800 "K" St., N.W.Suite 810Washington DC 20006701558-4166, 7 & 8DLC: 754

WEST PALM BEACH. Florida

Dato. G.(Gus)

E xt. 383/384

Dover. H W(Herb)

Ext. 385/386

Tracy. E. C.(Ed)

Eat 387/388

Fitch, F. C.(Cary)

Thursby. G(Gary)

Ext 6061

Koriwchak, C.(Chuck)

Ext 453

DEPT. HOME ADDRESS

B 1314 Comanche DriveRichardson TX 75080214.231-6090

G -CC 2020 Custer ParkwayRichardson TX 75080

214-231.4185

3710S.Hillcrest DriveDenver CO 80237303-758-0647

B

B

G.CC

B

B

23680 Oak GlenSouthfield MI 48075313.352.9320

7825 Greenbush AvenueVan Nuys CA 91402213782-6876

612 Seclusion LaneGlendale CA 91206713-246.7984

860 Misty Isle DriveGlendale CA 912072112401298

740 Oaks Alyson Ct.Jacksonville FL 32211904-724-8726

3102 W. 73rd TerracePraire Village KS 86208913432-6126

148 8rookdele CircleMcMurray PA 15317412.941.7848

Eberhart. W. G. B 6224 Chowen Avenue, N(Woody) Brooklyn Center MN 55429

612-561-4615

Shipley. J PIJohn)

Ext. RR -8567

Verde. R.(Roy)

Ext. RR -5206

Newman, R. J.(Dick)

Eat 333/334

Freeman, D(Dirk)

Ext 345

Harding. R. E.(Ray)

Emch, R. S.(Bob)

Ext. 4233/4/5

Huffman. F.(Fred)

Ext. 4212/3

',Adv. E. N.. Mgr.(Noel)

ConsultantRelations

3900 RCA Blvd. Giles. R.Palm Beech Gardens, Bldg. 110 (Roy)West Palm Beach FL 33403 Ext. 2891305-622.1100 2892DLC 834

B

B

B

752 Paddock PathMoorestown NJ 08057603.234 1741

456 Patton PlaceWyckoff NJ 07481201-891 5177

3303 Verdun AvenueSan Mateo CA 944034153456306

B 1017 SherbrookSt. Charles MO 63301314-946-6515

B 5615 80th Ave., S.E.Mercer Island WA 98040206.232-6015

G.CC 6016 Rossmore DriveWildwoxl ManorBethesda MD 20014301-5300775

B 8511 F srburn DriveSpringfield VA 221507034518685

11121 Hurdle Hill DrivePotomac MD 20854301-299-7585

8 10345 Acme RoadWest Palm Beach FL33401305-6833404