I am assisting the owner with the sale of his Technical Materiel Corporation (TMC) model GPT-750-2 transmitter. This unit is the later and more common Mark-II (or -2) version; it is in very good cosmetic condition, and is complete with the exception of the center drawer, which was used to mount the optional model SBE SSB exciter, or the model XFK frequency shift keyer unit for RTTY operation. As users of the GPT-750 nowadays will most likely want to run this rig on AM, and build their own modulator unit into the area reserved for the center drawer (or external to the transmitter), the lack of the center drawer should not be an issue.
The GPT-750 uses a pair of 4-250s (most have been re-tubed with 4-400As) for an easy 1000 watts input of plate modulated AM, and it is continuously tunable over the range of 2 to 32 Mhz. A simple modification to the final tank circuit permits the transmitter to tune down to the 160 meter band.
My understanding is that the transmitter was in operating condition when it was removed from service and sold to the current owner; he has, however, never put the rig on the air.
GPT-750s are large, heavy, and overbuilt transmitters, built for continuous 24/7 commercial or military service. The oil-filled and sealed plate transformer alone weighs 110 lbs, and TMC did not cut any corners in the electrical or mechanical design of this rig. As several GPT-750 users on this board can attest, they make wonderful transmitters for those desiring to run high power plate modulated AM anywhere in the HF spectrum.
Full details and copies of the original TMC technical and operating manuals for the entire GPT-750 series can be found at the following link:
http://jptronics.org/radios/TMC/manualsThis transmitter is reasonably priced at $1500.00, and is located in the Gaithersburg, MD area. I can forward photos of the rig to any interested party. Feel free to PM me at
triodes@optonline.net for further information.
Thanks & 73,
Bruce
