The work done yesterday was focused on adding more wire connections and installing components on the 12GE5. We have a day or two more of this same type of work.
The Final Tank circuit will need some testing to assure optimization for maximum efficiency.
Wires and More Wires
We started a bit late in the morning as we made our usual Friday visit to the cemetery to perform a little gravesite maintenance and of course bringing fresh flowers.
The real work effort was spent redressing wire connections that were unsoldered as we looked for the shorted PTT line. Other tasks added more parts and circuitry to the 12GE5 final, and I wired in the Main TR Relay. I wish the 1st smoke test could be this weekend but that will not happen. Also installed was the wiring for the Cathode meter.
I spotted something in a Heathkit design that I had not seen before, and this is in their HX-20 SSB transmitter design. This particular rig was intended for use along with the HR-20 matching receiver. The cutesy thing is how they developed USB/LSB and how that was frequency translated to multiple bands.
Essentially it is multiple conversion design where the SSB signal is generated at 4990 kHz and then the slick part where after passing through a 4990 MHz Crystal Filter is mixed with either a 4010 kHz signal giving a 9 MHz USB signal or a 13990 kHz signal to give a 9 MHz LSB Signal (sideband inversion). Later heterodyne signals are mixed with a 5 MHz VFO that translate this 9 MHz SSB signal to other ham bands. Nice trick Heathkit Engineers.
This has some great possibilities today with the use of the Si5351, maybe several of them, to generate the two mixing frequencies, the 5 MHz VFO and the heterodyne signals. You could rip out all the Analog VFO/Heterodyne crap in the HX-20 and turn it into a modern SSB Transceiver with a very accurate LCD display. QRP Labs used to sell programmable Si5351 crystal substitutes which would be perfect for generating the two frequencies.
There are Heathkit HX-20 Transmitters on eBay right now that can be had for less than $75. Some look like they are in pretty good shape. But Caveat Emptor, not for a Novice to take on as a project!
Note for a 4.9152 MHz Homebrew Crystal Filter the USB LSB frequencies would be 4.0848 MHz and 13.9152 MHz which are a piece of cake with a Si5351.
Them that know can make things go.
73's
Pete N6QW