My 12 volt version of the 1955 CW transmitter, which
used a 6AQ5 tube, very much akin to the Ameco AC-1 6V6 transmitters. I
make these to order, so please allow up to 20 days for shipment, once
purchased.
A
fused DC to rectified AC internal converter allows you to use either an
external 12 to 14 vdc battery, bench power supply, or simply plug in 3
of the 18650 batteries, as shown. In the latter case, this allows
portable use, with no external power supply required.
Two
binding posts are provided for connecting an external power source,
when used. In that case, remove the three 18650 batteries.
Any
external power supply should be capable of 2.5 to 3 amps, when
transmitting. A filament/standby/transmit, 3 position on/off switch is
provided on the front panel. High voltage is always on in transmit mode,
but off in the standby position. The center position turns everything
off.
WARNING!
Don't be fooled by battery power. In send mode, the internal dc voltage
produced to operate the transmitter exceeds 300 volts dc. This is
lethal and can kill you dead, if not handled responsibly, with the usual
respect that you'd give any high voltage transmitter circuit.
Please do not purchase this item if you cannot accept this reality!
Power
input is about 6 to 7 watts, which is sufficient for QRP work. I can
build these with a 6V6, 12V6 or 12A6 tube, but if a 6V6 is used, the
filament current drain is greater, so you'll need to recharge more
often, if using a battery power supply.
Constructed
on a 3D printed chassis, which is like a plastic material. Antique
brass is pictured, but several color options are possible. Please
inquire.
The
output tank circuit employs the typical Pi-network and will load into
any reasonable antenna impedance of 30 to 500 ohms, just like any of the
old boatanchor transmitters of the 50's era.
A hand-sketched diagram is included, along with one
plug-in coil and one QRP crystal for operation on all six HF bands,160, 80, 60, 40, 30 and 20 meters.
The CW tone will always be better
when using FT-243 crystals. You may encounter minor chirp with the QRP
crystals, especially on 30 and 20 meters, but the signal quality is
still quite acceptable. With careful tuning I can usually eliminate most chirp
issues.
Shipping to United States zip codes only.