high power transmitters for science
TRANSCRIPT
High Power Transmitters
for Science
Paul A. Bernhardt, KF4FOR
Plasma Physics Division
Naval Research Laboratory
Washington, DC 20375
High Power Transmitters
• High Power HF Facilities Around the World
• Ionospheric Effects
– Very Low Frequency (VLF) Wave Generation
– F-Region Irregularities, Waves and Fast Electrons
• HAARP System Description
– Antenna
– Transmitter
– Diagnostics
• Sample Experimental Results
– Artificial Aurora
– Artificial Sideband Generation
Ionospheric Effects on Radio
Wave Propagation and Systems
• Communications Range and Reliability
- (ELF - UHF/L-Band)
• Radar Accuracy
- Space SurveillanceRadars
- Space-Based Radars
- HF OTH (ROTHR)
• Navigation Errors
- GPS
IONOSPHERE
Reflection
Refraction
Time Delays
Phase Shifts
Scintillation, Fades
Polarization Rotation
Communications Surveillance
Irregularities
UHF SATCOM
GPS
Current and Future HF
Ionospheric Modification Facilities
Jicamarca
Arecibo
Conjugate
HAARP and other HF heating facilities
EISCAT Enhanced Airglow, Bjorn Gustovson, IRFU
Arecibo Dish in Puerto Rico
600 kw HF
Transmitters
Feeding HF
Antenna
Suspended
Over 324 m
Arecibo Dish
Sporadic-E Irregularities Glow by High Power Illumination
New Ionospheric Heating Facility at Arecibo Puerto Rico
Modifies the Ionosphere
Arecibo HF Facility Antenna Gain at
8.175 MHz Giving 220 MegaWatts ERP
Arecibo 430 MHz Radar Ion-Line Profiles Modulated by 5.125
MHz Transmissions by the Arecibo HF Facility on 9/10
November 2015(Sources: Nestor Aponte and Mike Sulzer, Arecibo Observatory)
Bac
ksca
tter
Po
wer
(d
B)
Off
On
23 00 01 02 03 04
Alt
itu
de
(km
)
Time (GMT = AST + 4)
64
60
56
52
48
44
40
630 nm Airglow Modulated by 5.125 MHz
Transmissions from the Arecibo HF Facility(Sources: Jeff Baumgardner, Boston Univ. and Juanita Ricobono,
Sci-Sol)
5.125 MHz HF Operation
Stimulated Electromagnetic Emissions Excited by
5.125 MHz Transmissions from the Arecibo HF
Facility(Sources: Stan Briczinski and Paul Bernhardt, NRL)
DM UM
Pump Pump
SBS-SMHD
Arecibo ePOP Passes for HF
CampaignDay
Nov
.
Center
Time
(GMT)
Duration
(Min)
HF
Mode
Freq.
(MHz)
13 5:46:43 6 (±180s) 00 5.125
14 5:31:26 6 (±180s) 00 5.125
15 5:16:09 6 00 5.125
16 5:00:52 6 00 5.125
17 4:45:35 6 00 5.125
18 4:30:18 6 00 5.125
19 4:15:01 6 00 5.125
ePOP Data TakenNov 13 05:42:44 - 05:48:44 6.25 with 62.5 Hz WRF, 8kHz
Nov 14 05:27:20 - 05:33:20
13/14 November 2015 Arecibo ePOP Passes
Ionospheric Affects From High
Power HF Heaters
• Increased Electron Temperatures
• Decreased Local Plasma Density
• Modulation of Electro-Jet Currents
• Field Aligned Irregularity Generation
• Artificial Aurora Optical Emissions
• Enhanced Plasma Waves
• Simulated Electromagnetic Emissions
Generation of ELF/VLF waves
F-Region Ionosphere
Stimulated Electromagnetic Emissions,
Radar Backscatter, Enhanced Plasma Waves
and Artificial Aurora
HF Radar HAARP Transmitter HF Receiver HF Receiver UHF Radar Camera
HAARP Research StationGakona, Alaska
Fall 2006
Site Location
Location provides a wide variety of ionospheric and space conditions that open up a wealth of research opportunities
HAARP Facility
Program History
• Program begins (1990-1991)
• Environmental Impact Study (1992-93)
• EIS completed. Antenna construction begins (Oct 1993)
• Initial scientific diagnostic instruments installed (Oct 1994)
• NTIA Certification to Operate (Dec 1994)
• First operation of the transmitter at 360 kW level (Dec 1994)
• First use of HAARP for research (Nov 1996)
• Transmitter upgrade to 960 kW completed (Dec 1998)
• First major research campaign (Mar 1999)
• Work begins to complete the facility (Apr 2003)
• Facility completed as originally envisioned (July 2007)
• Facility transferred to University of Alaska (December 2015)
The HAARP Gakona FacilityFall 2006
HF High Power
Transmitting Array
Operations
Center
UHF Diagnostic
Radar (MUIR)
Digisonde
Aircraft Alert Radar
HF Test Facility
Spiracone
Optics, Magnetometers,
Riometers
The HAARP Antenna Array
Each tower supports two
“Low band” dipoles and two
“High band” dipoles.
Each dipole is driven with an
independent 10 kW
transmitter.
Towers are spaced 80 feet in
both directions and dipoles
are aligned N-S and E-W
magnetic.
Each shelter contains 6 dual-unit
transmitters. Each transmitter
can provide 10 kW of output
power within the range 2.8 – 10
MHz at VSWRs up to 3.5:1.
Each shelter is surrounded by
six towers to which its
transmitters are connected.
Antenna Element Components
15 feet
43 feet
53 feet
Low-Band
Dipole
High-Band
Dipole
Ground
Screen
Ground(Marginal permafrost) Thermosyphon
AMU
AMU
30 feet
69 feet
Antenna Array Ground Screen
The Ground Screen uses approximately 200 miles of wire
Two Beam Operation
HAARP Array Generates a Hollow Beam
Antenna
Gain (dB)
Radiated Power 3,600 kW
Frequency Coverage 2.8 – 9.5 MHz
Antenna Gain 20 - 31 dB
ERP 86 - 95 dBW
(400 - 3000 MW)
Antenna Beamwidth 15° - 4.5°
Beam Slewing 30° from Zenith @ All Azimuths
Re-Position Time --------- 15 µsec ---------
Independent Beams 2
Polarization ----- LHCP / RHCP / Linear -----
Modulation Types AM/FM/Pulse/Continuous Duty
Modulation Frequency ---- 0 - 30 kHz Generally ----
Array Size 880’ X 1120’
Performance Parameters For
the Completed HF Array
Transmitter “A”
Power = 10 kW
East-West Dipole
Transmitter “B”
Power = 10 kW
North-South Dipole
Closeup of a Transmitter Cabinet
Common power
supplies and
controller.
Radio/Radar Based Diagnostics Facilities
for HF Ionospheric Modification HAARP HF Transmitter, AK
Kodiak SuperDARN Radar
SIERRA Spectrum Monitor
AMISR UHF Radar
Optical Observatory
HAARP Enhanced Airglow, Todd Pedersen, AFRL
The Ionosphere as Detector,
Oscillator and Mixer
High Power
Radio Wave
Transmitter
High Gain
Antenna
Audio
Frequency
Modulator
Oscillator:
Plasma
Resonance
Detector:
Electrojet
Currents
Mixer:
Parametric
Decay
Audio Frequency
Electromagnetic
Wave
Single Sideband
Electromagnetic
Wave
Ionosphere
High Power
Electromagnetic
Wave
Electrostatic
Waves
• Natural Currents Flow in the
Auroral and Equatorial Ionosphere
at 80-100 km
E-Region
Auroral or Equatorial Electrojet
100 km
• The HF signal interacts with the
plasma conductivity at 80 km
• The electrojet current is caused
to vary at the ELF/VLF rate
• Propagating ELF/VLF signals are
generated
ELF / VLF < 20kHz
Radiated ELF Signal
is Related to the
Power of the HF
Transmitter
HF Transmitter
Generation of ELF / VLF Waves In the
Ionosphere
1-hop Echo on Tangaroa
HAARP Experiments with an
HF Digital Receiver
• Transmission of Very High Power Radio
Waves Produces Waves at Other
Frequencies
– Pump Wave Excites Plasma Waves
– Plasma Waves Mix with Pump Wave to
Produce Radio Waves at Other Frequencies
– Process Called Stimulated Electromagnetic
Emissions (SEE)
F-Region Ionosphere
Stimulated Electromagnetic Emissions
HAARP Transmitter
SEE (Downshifted Maximum)
for Vertical Beam
B
SEE (Downshifted Maximum)
for Beam Field-Aligned
B
Processed SEE Data Near the Third Electron Gyro
Harmonic from the SIERRA Site at Glennallen
20 March 2004
DM
2DM
3DM
UM
BUM
Pump
In Situ
Source:
Upper
Hybrid
Waves
In Situ
Source:
Electron
Bernstein
Modes
SIERRA Spectrograms
Glennallen Site 20 March 20004
-18
0 H
z
-12
0 H
z
12
0 H
z
18
0 H
z
Stimulated Brillouin Scatter with
Ion Acoustic Wave Generation is Simple
EM1
IA1
EM2
SBS-1
B
Pum
p
SB
S-1
f IA1
q = 0
B
Brillouin Scattering of the 4.5 MHz
HAARP Vertical Beam
in the Ionosphere
Offset (Hz) from 2.85 MHz
Offset (Hz) from 2.85 MHz Offset (Hz) from 2.85 MHz
03:55:10
03:56:50
SBS at UH Level for Underdense HF
Stimulated Electromagnetic Emission Spectra for
(a) Lower Hybrid or Downshifted Maximum and (b) Ion Bernstein
During Periods of Artificial Ionization Production at HAARP
Off
se
t (k
Hz)
from
2.8
5 M
Hz
Off
se
t (H
z)
from
2.8
5 M
Hz
Absolute Time Offset (s)
Date 2009/03/17, Time 05:13:00
(a)
(b)
SLH/DM
SIB
-220 Hz SEE Line Strength
SIB-4
220 Hz
20
10
0
Optical Emissions from N2+
42
7.8
nm
In
ten
sity (
R)
427.8 nm Data from Todd Pedersen (AFRL)
SBS with EIC Generation Yields Ion MassO
ffse
t F
requency (
Hz)
Radio Beam Angel with B (q)
B q
f EIC
-1
f IA-1
111.1 Azimuth 16.3 Zenithmi = e B/fEIC
= m[O+]fEIC-1
fIA-1
-18
0 H
z
-12
0 H
z
12
0 H
z
18
0 H
z
HAARP Amateur Radio Club Station
KL7ERP
HAARP Transmit array under
the natural aurora
The End