Navy Shore Station LF & VLF Transmitters

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Shipboard Transmitter & Transceivers
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MYSTERY		LF 100KW FRT-72 or something else? Bouknadel 1970 (thanks to Darian Paganelli)	Manuf by Continental Electronics? Please send e-mail if you have more info on photo to left
AN/FRT-3		1400 kw VLF 24.8kc RTTY & CW installed at NLK Jim Creek WA	manuf by RCA
AN/FRT-4		55 kw LF 50-150 kc similar to TCG-2 except air-cooled	spec sheet NAVSHIPS 91169
AN/FRT-10	need photo	500 kw LF 100-200 kc CW/FSK - spec sheet dual 250 kw transmitters, diesel engines for p/s installed at Guardamar, Spain Info from John Cobb: "The AN/FRT-10 was unique, a 500 kW LF giant tuning 100 - 200 kHz. It was in two amplifier bays, which we drove alternately with an external TMC synthesized exciter stack, running the single-channel KSUB broadcast at about 50 kW. It fed a 1200-foot tower, through 8-inch rigid coax and a big variometer/capacitor network in the helix house. The amplifier bays each consisted of IPA and driver stages for the finals: four air-cooled 6697 triodes in grounded-grid push-pull configuration!"
AN/FRT-19		15 kw LF 30-300 kc CW/FSK 3 kw LF 300-600 kc CW/FSK Used in AN/TSC-35 transportable COMMSTA - and elsewhere?	Manual NAVSHIPS 92117 Manuf by Serria Electronics
AN/FRT-31		2MW VLF (17.8 / 24 kc) installed at NAA Cutler, ME four separate 500-kw final amplifiers, each with eight ML-6697 air-cooled tubes operating in push-pull parallel More Cutler & FRT-31 photos and info	Manual NAVSHIPS 94356 Manuf by Continental Electronics cost $2,530,814
AN/FRT-61		100 kw peak, 50 kw average 50-150 kc CW / FSK Used in AN/TSC-35 transportable COMMSTA - and elsewhere?	Manual NAVSHIPS 94592 Manuf by Continental Electronics cost $299,633.
AN/FRT-64	photos	1MW VLF (21.4 / 23.4 kc) installed at NPM Lualualei, HI 15-30 kc, 1 MW similar to AN/FRT-31 but with water-cooled finals FSK +/-25 cycles 2400 kw plate xfmr weighs 93,500 lbs!	Manual NAVSHIPS 95884 Manuf by Continental Electronics photos
AN/FRT-67	need photo	2MW VLF (19.8 / 22.3 kc) installed at NWC Harold E. Holt, Australia	-
AN/FRT-72 AN/FRT-72A	Bouknadel 1970 (thanks to Darian Paganelli)	100kw peak, 50 kw average 30-150kc	NAVSHIPS 0967-033-8000 manuf by Continental Electronics Note - FRT-72's from Driver, Grindavik, and Thurso were moved to Colorado for use at WWVB - photo here
AN/FRT-87	need photo Click Here for photos and info	1 MW VLF installed at NSS Annapolis, MD Click Here for photos and info	Manuf by Continental Electronics
-	Info from Roy K1LKY "I was fortunate to visit the VLF station at NSS Annapolis before it was dismantled. On that trip we learned that the narrow shift FSK keying put the carrier alternately on either side of the center of the tuned system. It was some 10 percent down the slope (memory of the details are faint.) But the antenna current was monitored at the console and would vary depending on how far down the slope the tuning had shifted the center of the very narrow sweet spot. The operator could vary one of the inductors in the system by remote control to match the two currents. That system operated at 20.4 kc I believe, at an output power of about eight tenths of a megawatt. The shift may have been on the order of 10 to 15 CPS. The antenna was one mile long, about 800 to 1200 feet up, and was tuned with a massive inductor made of five inch diameter Litz wire. Cutler Maine still operates with similar parameters, as far as I know."
AN/FRT-95	need photo	modern solid-state VLF installed at Aguada, PR	-