Hi Annas
Having built several Transmitters and Receivers, Valve ones are SO much simpler (less stages required) . . . and they usually work straight away ! (unlike Transistor ones, where there's often issues to sort out). Plus no PCBs needed, all the components just hang off the Valve bases, mounted on a chassis. A valve CW Transmitter for 160m is VERY simple . . . the VFO is on the signal frequency, and just two valves will give you ten watts - ECF80 VFO/Buffer, 5763 PA. Add a 6146 or 807 and you will have 100 watts input (80 watts output, as Class C) If you want to make Transceiver, then you will have to have a VFO on a different frequency and Mix (so the Receiver is a Superhet) . . . but the advantage with 160m is that you can have Single Conversion from 455 kHz, so it's easy to make a stable VFO around 2.3 MHz. You'd just need to find a nice cheap second-hand 455 kHz CW Filter . . . copy some of the Receiver stages circuitry from any Valve Rx (R4B, FR400, etc) . . . so something like a 6BW6 RF stage, 6BE6 Mixer, a couple of 6BA6 IF amps, and an ECL86 Audio Preamp/Output valve. Plus a 12AT7 as a Carrier Osc and VFO. On Tx you simply use most of the same circuits in reverse, with a similar output stage as outlined for the Tx above. I built a few SSB Transceivers in the 70s using that kind of circuitry . . . but a CW one is simpler as you don't need a Mic Amp or Balanced Modulator, and you don't lose any Tx signal through the Crystal Filter (as you'd bypass it) 73 Roger G3YRO _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
