73 ReviewNumber 1 on yOI' ~backcaod

by Steve Katz WB2WTKl6

Alden Corporation147 New Pal1\. Road

Franklin Square NY 11010Telephone: (516) 328-7501; Fax (516) 328-7506

Price Class: $409

The Azden pes-7200A solid 222 MHz Mobile FM transceiver.

Initial Use and Programming

There are a couple of downsides to the Az­den. One: The documentation is a bit lacking.The PCS-7200 does not have its own instruc­tion manual, but uses the PCS-7(X)() (2 meterrig) manual, with an -Addend um· sheet toclarify the differences. The PCS-7000 manualhas typographical errors and other mistakes,a nd us in g it wi th an · A dd en d um- sheetmeans referring back and forth between twopapers to get things right.

Secondly, the Azden is not particularly "us­er friendly," and requires real study of the in­struction manual. Probably the most impor-

tant thing to know for FMelS ishow to program a transceiver'smemories with frequency, offsetand tone data . The Azden issurely programmable, and has20 memories which do store allthe impo rtant data-but the in-st ruction manual uses a pagea nd a hall of text d escribing

how to do It, and until you've programmed theradio a few times, ir s a nearly incomprehen­sibl e task. As I've said in other product re­views, 1rate new equipment for 'user friendli­ness" based on whether I can figure out howto do everything req uired without ever refer­ring to the instructions. With the PCS-7200,to program each memory you must push thePAOG(WR) key six times , and make otherkeystroke entries as well. It's a task tha t onlySu perman could accomplish while driving thefreeway, although I'll admit that once I hadprogrammed the f irst l ew, the rest of thememory channel programming went quitewe ll (at home, on the bench).

like the PCS·7500H 6 meter rig , the PCS­7200 defaults to memory . /4l1' (the first of itspossible 20 memory channels) on power-upand does not remember where it was lastused. This can take a bit of ge tting used to, ifyou're accustomed to other popular brands ofFM gear. Also like its 6 meter brother, the72oo's memory storage is on ly accomplishedby turning the rad io off at the end of the pro­gramming sequence . The following NOTEappears in the manual: "Be sure to turn offthe power when you have completed pro­gramming. This procedure is required to geteach setting programmed in and th£n to get

The PCS-72OO comes factory-equipped witha PTTfDTM F (-ToUchTone-) mic rophone ,mike hanger, DC power cord and spare fuse,mobile mounting bracket and hardware, andowner's manual with schematic diagrams.Like most Japanese gear, the Azden doesnot come with any real service information,but Azden does offer a two-year limited war­ranty, where all repair costs are borne by thecompany for the first year and the cost of re­placement parts (but not labor) are coveredfor the second year.

U.S. where every class of licensee has vo icep rivi leges, and Novices cut their t eeth on"phone" da ily by making contacts on 222MHz.

The Alden PCS-7200 is an excellent en­try-level radio for newcomers and okf-limersalike. With 25 watts output power and a sen­sitive, selective receiver, if s a "wotkhorse· ra­dio that will serve a variety of needs h omsimplex to repeater, to eutooatcn. to packetwork. It' s a pretty radio, like the other Azdenmobiles, and is a pleasure to just look at , withIts deep orange-backlit LCD display and or­ange-illuminated microphone pad buttons.

"I don't know how things arewhere you live, but here in Southern

California 135 em is almost aspopular as 2 meters. "

The Azden pes-7200 may be a lilli e­known entity, but il is alive and well and

putti ng Qui good si gnal s on 135 em FMaround the country. and likely elsewhere. Al­den is not one of the "big tnree" Japaneseham equipment manufacturers , and theydon't make HF·SSB equipment. But like Alin­co, they make some very usable VHF·FMgear that should not be overlooked when it Istime to go Shopping for that new rig.

Azden's "ctatm to fame," so 10 speak, isthai they manufacture bUdget-priced mobileand portable transceivers for 50 and 28 MHzFM. Although Azden has been around selling2 meter rigs for 19 years now,they have little oompetition in the6 and 10 meter a rena , whichmost manufac1urers have chosento almost ignore. But Azden alsomakes high-quality FM rigs lor144, 222 and 440 MHz, and thePCS-7200 is one of only two 135c m FM mobi le mo no bandtran sceive rs c u rre ntly on themarket.

I don't know how things are where you live,but here in Southem california 135 em is al­most as popular as 2 meters. There is con­siderable simplex activity and a Qreat numberof high-level 222 MHz repeaters occupy ev­ery single available c hannel on the band.Many of these 'rnactsnes" offer autopatch, al­most unheard of on 2 meters In densely-pop­ulated areas; and coverage on 135 cm is al­most exactly the same as it is on 146 MHz.This is the only popular amateur band In the

32 73 Amateur Radio Today . March, 1995

"While most handie-talkies and somemobile radios just roll over and die

under the pressure of zillions ofhigh-level signals pouring down the

antenna feedline, the Azden doesn't. "

out of the programming mode: Weird . but itwcocs.

The PCS-7200 is able to program any fre­quency offset r splir) on every single memorychannel, which is a plus in my book. (Al ­though all our local repeaters here use a mi­nus 1.6 MHz offset, anyway. But thai could el­ways change, and it might be.onterenr else­where.) However, because the Azden lacksany preconceived 'offset" of any kind, whenprogramming lor use, one must enter boththe transmit and receive frequency for everysingle channel intended. This is quite differ­ent from other FM mobile rigs 00 the market.and takes a bit more time to accomplish. Th isisn't a big deal if you do all your programmingat home and then inlend to keep the memorychannels as they are for a long time, but ilcould be an inconvenience lor those who fid­dle around a lot and like to change memoriesdaily.

A "tempo rary memory" Is also available,and does nol occupy one of Ihe main 20memory channels. Unfortunately, using thisfeature is 100 complex to be ofmuch use when driving, so il susefulness mighl be limited 10fixed operation , w here o n ecould use the 'emporary" mem­ory like one addllional channel.

Also, the PCS-7200, like thePCS-7500H, uses a "Tone CodeTable" as a reference for CTC­SS r PL" tone) programming .Thai is, if vou wish to program a"PL" lone of 156.7 Hz, Ihis corresponds 10Tone Code 125. When entering "PL" data intothe Azden, the lOne code display is a two-dig­it one. COl'Tesponding to the Tone Code Tableprinted on page 14 of the inSlruction manual.If you don't have the manual with you andneed to enter some unique "PLY lone on Ihefly, YOU'll be hard pressed to remember whichtwo-digit code corresponds 10 which lone. Allthe standard 38 CTCSS tones are in there,but it's nearly impossible to remember whichone is wt1ich without the Table .

The Workhorse

The PCS-7200, fOf all lts quirks, actuallyworks very wei. They call it a "MIL-STD-81O"radio, wtlich I assume means it is nol actuallymilitary qualified, but is built to withstand theenvironmental extremes specified in this mili­tary document. I live in a "high-RP environ­m ent thai makes many inexpen s iv eVHFNHF rigs 90 bonkers with lntermodula­lion products and receive r images: I'm up ona rise with a clear view lor 20 Of 30 miles insome directions, and mat view is of a targecity with COlI'ltIess high-powered transmitterspoplJaling every hilltop. I'm also jusl · under"a popular 3600'-h igh mounta intop bristl ingwith so many transmitting antennas it ap­pears much like a porcupine from here. Whilemost narce-taudes and some mobile radiosjusl roll over and die under the pressure ofzillions of high-level signals pouring down theantenna teecnne. the Azden doesn't. It justsits there, receiving even weak, distant sig­nals, without a trace of "inlermed: Its 25-watt

transmitter is competitive enough (althoughsome 222 MHz rigs run 35 watts, lhis is only1.46 dB more power, hardly 'NOrth discussing)and is rock·solid. After 10 full minutes of con­tinuous key-down time (OK, so I'm long-wind­ed !), the Azden's power output doesn't fa ll off.Many of the "so-wetr 2 meter rigs start outrunning 50 watts or more when cold, but winddown to maybe 40 watts afte r se veral min­utes of key-down time. The 25-watt Azdendoesn't do this, and would probably make agood ' remote base" unit capable of rather se­vere service.

Another "pIus· in the Azden's favor is its re­mal1<able receiver audio output stage andspeaker. The rig is rated to produce 2 wattsof audio power into an 8-ohm load at 10%maximum THO (total ha rmonic d istortion) ,and it sounds loud, much like a commercialradio . I never had to crank up the vol umecontrol more than about halfway 10 produceroom-filling (or ca r-filling) volume. The rig'stop-m ounted speaker is also top-notch anddoesn't rattle the little rig 's cabinet, even with

the vol ume fun up. This may sound insignifi­cant, but I think it's a wonderful feature for amobile rig----one I miss dearly when a rig can'tprovide enough receive audio to overcomeroad noise when operating mobile .

Other Features

The memory and band scanning featuresof the PCS·7200 are as good as those foundin any rig I've used. One can scan just thememory channe ls i n · Ban k A" (10 , AOth rough A9), " Ban k B" (a nothe r 10, 80through B9), or both A and B. When in the"direct" (VFO, non-rnem<:MY) mode, the rig wi llscan between any two frequency limits ; how­ever, those lim its must be stereo in memo­ries. For example, you could store 222.01 inmemory A8 and 22 4.99 in memory A9 andscan between these two limits, thus coveringthe entire amateur band. You could store an­other set of lower and upper limits in memo­ries B8 and B9, and scan Just between lhosetwo. Push ing the PTT button on the mike,or depressing the UP or DOWN keys , theREV(erse) key, the M(emory) MODE key orthe F(unclion ) key will slop me scanning ,which may be immediately resumed by de­pressing the SCAN key again . The only prob­lem is, if your scanning rece iver stops on arepeater frequency which was not previouslystored in memory, you can't just grab for themike and start chatting on that channel. Th isis because the rig won't know exactly whereto transmit It does not have an automatic re­peater offset function.

Like most modem FM rigs, tI1e Azden also

contains a PRIORITY mode feature. Activat·ed by depressing the PRI(ority) key, tI1is tee ­ture enables the receiver to look for activityon memory channel AO (automatically thedesignated priority channel) every fou r sec­onds, regardless of where the receiver is ac­tually tuned . If aCtivity is present on me priori·ty channel , a "beep" tone sounds in thespeaker to alert you. A momentary press ofthe M AO key on the front of the PTT handmike Immediately switches the rig from what­ever channel it was on 10 the priority chaMel(AO). II you make this fast frequency changeand then decide vou didn't rea lly need to, an­othe r momentary press of the same key willreturn you to the last channel you were onbefore switching to the priority frequency. Ifind tI1is feature very handy, since I really dohave a p rio ri ty freq uency around here­222.080 MHz, a popular simplex channel forthe San Fernando Valley.

The factory-supplied PCM-499-23 dynamichand mike contains a 16-key DTMF (T0lJCh.Tone) encoder, as well as UP/DOWN (fre­

quency select io n) buttons , the"M AO" (priority channel) buttondescribed above, and a ruggedcoiled cord with attached 8-pinconnector. The 16 keys are allsoftly lighted the same color asthe Azden's panel displays, mak­ing butto ns easy to fi nd in theda rk . (I wish all mob ile micro­phones had lighted keys!) TheTouchTooe encoder produces an

audible sound from the microphone itsel f , soyou can tell if it is working . However, thePCS-7000 manual contains some miSleadinginformation regarding operalion: It states, "Toenable the DTMF encoder function, press thekeypad keys correctly In the desired se­quence. As each button Is pressed, the LEDwill light. The transceiver is automatically putinto the transmission mode when any keypadis pressed . The built- in 'hang timer' causesthe transmitter to operate continuously if thedelay between keyslrokes is less men 2 sec­onds."

I didn't find any of this to be true. Depress­ing a key does not make the transmitter oper­ate. I had 10 depress the PTT button on theside of the mike first. As for the "LED" light­ing, there was no LED on the mike suppliedwith the review unit , so I don't know whatLED they're talking about. Also, the "hangtimer" doesn 't exist on the review unit. If yourelease me PTT button , even if you're in themiddle 01 a keying sequence on the tone pad,the rig stops transmitt ing . All these "faul ts"are fOfgiveable, but I wish Azden would up­date the manual 10 make it less confusing forneophytes wt10 may actually become upset ifthe rig doesn't operate exactly as described.(In speaking with Azden since the review unitarrived, I determined that the new PTT mikedoes not function as described in the insnuc­ticn manual, and thai is normal. They saymost users did not like the "push any buttonand you're transmitting" function, so theyhave revised th is to be as I have describedabove.)

34 73 Amateur Radio Today. March, 1995

Table I. PC5-7200 Tests and Measurements

Note: PCS·7200 receiver can detect very readibIe Sigl'IalS before its s -eeie- bargraph!isplay indieatesany signal present.

All data taken by WB2WIK 12f26194.

S-meter and power output meter bargraph display:PCS-7200 uses a l a -seg ment display but segments 9 -t 10 illuminate together, making for9 inc rements of resolution.

Bargraph reading !Or full (25 W) outPut power. 10 segmentsBa rgraph reading for low (5 W) output power. 2-3 segmentsSometer reEdngs vs. input Signal strength:1 bar. 0.45 pV2 bars . 0.55 pV3 bars . 0.65 jlV4 bars . 0.75 jlV5 bars . 0.87 jlV6 bars . 0.95 JiV7 bars . 1.351l-V8 bars . 2.00 jlV9 bars .. 5j1V

O.28A SQUelchedO.55A oosquelched

1st IF (21 .6 MHz), 102 c a2nd IF (455 kHz), >136 dB

31.6% (high)17.4% (low)

12.3 kHzI-6 ee28.5 kHzI-60 ea

2AW, 10% THO

0.10IN threshold0.45 ",V 20 dB NO0.27 ",V 12dB $ INAD

5.5A23A

24W5.5W

2SC2407) has "APC" (automatic power coo­trol) bias applied by the APC control circuit,which contains the HII1..0W power switchingtunction ancl power ootpuI level adjustmentslor both HI (VA9) and LO (VRB) ranges. Biasfrom the APC circui t is also applied to thefinal RF power amplifier, IC501, a ToshibaS-AV15 hybrid ("brick~) module located on therear heatsink of the radio. The transmitteroutput from IC501 is filtered by two separatedual pi-section low-pass networks. Also locat­ed on the PA board is the transmit-receive(TlA) diode switch, wh ich uses a pair ofH1407s. one in series with the transm itter.and one in shunt with the receiver, to performthe switching function. 1 am unfamiliar withthe HI407 and do not know if this is a P-I-Ndiode or not (but I hope so, as PINs are farbetter RF switches than co nventional P-N

Audio outpuI power:>2Winto 8 ohms. 10% THO

Receiver current drain; 13.e vee nominal source0."

ReceMtr selectivity.12 kHz min (total BW) at -6 dB30 kHz max (Iotal BW) at -60 dB

IF rejeclion :Unspecified

Transmitter overall power elhciency. Pout(W)/Pin(W);Unspecified

Receiver sensitivity:<0.12 JiV at squelch threshold<0 .35 pV lor 20 dB NO<0. 19 uv lor 12 dB SINAD

Transmitter curren!. drain: 13.8 VOC t'lOrrinal source6.0 A (high)Unspecified (low)

Transmitter output power. 13.8 VDC source, 50 ohm load25 wans (high)5 watts (low)

SpeclfleatlonFrequency range, 2 15-230 MHz (RX)222-224.995 MHz (TX)

audio response before driving IC10, a 3.4kHz integrated low-pass filter which rol ls offnoise and voice harmonics above the rangeof human speech. The speech audio fromthis filter is applied to the DEV(iation) controlVR4 and then directly drives the integratedVCO UNIT (ICB). the same system whi chprovid es local oscillator injection for the firstreceive mixer. The voltage-control led oscilla­tor provides frequency-modulated signals di­rectly in the 222 MHz range on transmit, soonly RF power amplifICation. ancI no frequen­cy mUltipliCation, follows this stage. This sure­ly reduces "phase noise" on the transmittedsignal and helps assure close-in spectral pu­rity.

The output from the VCO is amplified bythr ee cascaded bipolar stages (0 11, 0 12,013). The last of these stag es (0 13 . a

Inskfe the Radio

Let me lake a moment to describe the ra­dio's -guts: SignalS entering the receive rfrom the antenna )ack pass through a diodeTIA switch (hooray-oo relay!) to a 215-230MHz bandpass filter which is varector-tuneoto resonance by a special "loop filler" circuitprogrammed by VCO data. Signals are thenamplified by a 3SK177 dual-gate MOSFETand bandpass-filtered once again by still an.other varactor-tuned circuit before driving thefirst receiver RF mixer. All this "track-tuned"bandpass filtering is probably what makes theAzden 's receiver so immune to interferencefrom outside the amateur band . The first mix­er is another 3SK177 having LO injection at200.4 to 203.4 MHz (for tuning 222.0 to 225.0MHZ), provided by a 2SC3838 -RX Lo AMP"buffer stage which receives its local oscillatorsignal from the VCO UNIT which is commooto both the transmitter ancl the receiver. Thereceiver's first IF at 21.6 MHz is shaped by a15 kHz bandpass crystal filter and this IF sig­nal is then applied to "IC7,. the receiver IFsubsys tem wh ich co nta ins a bipo la r(2SC2715 common-emitter) IF amplifier, andan integrated circuit (MC33610) containingthe second local oscillator, second mixer.second IF ampl if ier. d i scriminato r andsquelch c ircuit. The second L O ru ns at21.145 MHz and produces a second IF at455 kHz. which is bandpass-shaped by a 15kHz multipole ceramic filler.

Demodulated signals from the IF subsys­tem are applied to a bipolar 2SC2712 audiopreamp whose output is high-pass filtered byan integrated -HPP 270 Hz rollott filter (tost rip away CTCSS "PL- tones from beingheard) before being postamplified by a powerintegrated audio amplifie r, IC5 (a TA7252).The receiver circuit contains cure r nicetieslike a th ree-stage "S METER AM p· circuitthat amplifies then rectifies the 455 kHz fil­tered 2nd IF signal and an "AF MUTE~ gatewhich switches off the drive to the final audiopower amplifier on transmit. All in all, a goodreceiver design that results in sparkling per­formance under real·woOd conditions.

On the transmit side. speech from the mi­crophone is first adjusted in level by a ~M IC

SENS" (mike gain) control VR2 before beingappli ed to an integrated MIC AMP stage ,ICll , which both amplifies and shapes the

I like the mobile bracket Azden supplieswith the PCS famity of mobile rigs: uncompli­cated, unobtrusive, sturdy and easy. Two ofthe four radio-mounting machine screws haveattached plastic knurled surfaces which allowhand-tightening with no need for tools. Theother two machine scre ws do req uire aPhillips screwdriver, but at least you can getthe radio mounted tempora ril y. w ithout itfalling in your lap or on tte floor, while youcasually ireten the remaining two screws.This is a thoughtful touch. I also like the sa­den schematic d iagrams. which are la rgeenough to read without an eye Ioupe and in­clude a block diagram that clearly details (atleast for the technically inclined) what's actu­ally happening inside the rig.

36 73 Amateur Radio Today · Man::/l. 1995

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junction diodes, having less loss and betterdistortion product perfonnance). Between thefirst dual pi-section TX fitter and the series RFswitch diode (and the second set of dual pi­section filters) is the directional coupler sam.piing network. which uses a 1$$1 06 detectordiode to drive the APC amplifier system.

Again, the transmitter circuit appears to bethorough, complete and designed with mini­mal adjacent-channel interference in mind.Although I pointed out some shortcomings indocumentation and operator conven ienceearlier, I must adm it Azden does a prettygood job of making radios that work , evenwhen the going gets tough. The PCS-7200contains circuitry not always seen in amateurgear ancl more frequently found in commer­cial two-way equipment. I applaud their RFengineering, and only wish they'd make thisrig more ~user-friendly" without the compli­cated cha.mel programming sequence.

I got the review unit programmed with 20chamels of local simpleK and repeater activi­ty, made a few dozen contac ts (inclUd ingbringing up some repeaters more than 150miles distant not bad for a as-wen radio!) andthen spent a few hours con ducting "benchtests" for receiver sensitivity and selectivity,and transm itter ou tput po wer and currentconsumption. The results of my testing areshown in Table 1.

One additional comment I might make re­garding the PCS-12OO's transmit modulation:When I first tried the review unit, I receivedreports of unc lear s ibilancy (ha rsh ·S~

SOtKIdsl, and "poppjng~ B's and P's. I repot­ed ~s back to Alden, who promptly providedme with another microp hone. The secondmike sounds the same as the first. Azden'sCommunications Division Manager, Sid WolinK2WH, recommended I try speaking acrossthe mike, rather than directly into it, becausethis is a noise-cancelling microphone de ­signed for the "talk across" technique. I triedthis, but still received reports of uncrisp mod·ulation. listening in a second receiver withheadphones, I must admit the modulation isnot as crisp and clear as I'd like it to be .Some of this is attributable to the noise-can­ceiling dynamic microphone; when I tried ad ifferent b rand of ·desk~ microphon e, itsounded better and more natura l. I won' tdowngrade the PCS·7200 for this , but mustrelate the experience in the interest of accu­racy. Azden boasts about their "t rue FM"modulation (as opposed to phase modulation ,used by some other FM transmilters), butwithout a be tter microphone transmit audioisn't all that great.

In all, I like the PCS-7200. What ttlacks inease of setup and documentation it makes upfor with good, solid RF performance. Azdenused to sell their products only "factory direct"in the U.S.; however, I see that Amateur Elec­tronic Supply now distributes Alden products,and pel1'laps others wi ll follow. The companyhas a loyal following among 10 and 6 meterFM enthusiasts, and there's no reason for135 em (and probably the other VHF band)users not to ta ke a serious look at thei rproctucts. II

73 Amateur Radio Today. March, 1995 37