Bc-696a Command "arc-5" 3-4 Mhz Transmitter Working Condition, 12 Volt Filaments

US $110

Rising Fawn, Georgia, United States
Oct 31st

Open on mobile:
QR code

BC-696A "ARC-5" U.S. Signal Corps. Command Transmitter 3-4 MHz These are commonly referred to as ARC-5 transmitters. Made by Western Electric Serial Number 29699. Standard Ham radio modifications include: ---the filaments have been rewired so that the required power is 12 Volts AC or DC for the filament and 150-250 for the oscillator plus 200-550 volts DC for the final plates. --some modifications to the wiring on the three rear octal sockets, I suspect this may to allow optional use of a tube type VR tube but haven't confirmed or traced this wiring. --The calibration crystal and "eye" tube are removed. ---A lead to the final cathodes has been brought out to a jack on the front. This allows CW keying. ---A knob has been added to the side to allow you to "dip" the final plate tuning. ---A silver mica fixed capacitor has been added at the output terminal to allow better loading into 50 ohms. The loading inductor has been replaced by a small fixed inductor to better match 50 ohms. The load is adjusted with the original control. The original variable antenna coil will be included in the sale should you wish to reconnect it for loading into long wire antennas, or use for other projects. --The output terminal has been replaced with a UHF type coax connector for 50 ohms. The original antenna terminal will be included in case you want to restore it. ---A few unneeded small parts have been removed. This does not affect the operation. See interior pics for details. Check the photos for condition and to verify all modifications. NOTE: the photos shown many missing screws for the covers as I opened this up for pictures. All screws will be replaced before shipping your purchase. The transmitter has been powered up with 12 volt AC filaments and an adjustable 150 to 350 volts DC to the oscillator, screen (via a resistor) and final plate. The power can be set from near zero to up to 10 watts with 350 volts DC (single supply). If you want to run more power, use a separate plate supply to the finals and you can get 25 watts plus out or more depending on how far you want to push the DC supply voltage. As a QRP transmitter, signal generator or VFO it is amazing that the transmitter works with less that 100 plate volts to the oscillator and final. I will double box this and use lots of bubble wrap so it arrives in good condition. NO RESERVE AUCTION.