I am happy to report great progress on the Mythbuster project. I have the receiver working on both 75/80 and 20 meters. And it in fact inverts the 75 meter LSB signals, turning them into 5.2 MHz USB signals for passage through my 5.2 MHz USB filter/BFO combo. No switching or shifting of the BFO is needed.
I am following Farhan’s BITX20 advice — I have paused in the construction and am enjoying the receiver that I have built. I’ll build the transmit circuitry later.
Inspired by Frank Jones (you really should be reading the FMLA articles) I have this rig prototyped “Al Fresco” on a pine board that I found discarded on a neighbors front stoop.
There is no RF amplifier in this rig. Following the advice of multiple receiver gurus, I ran the BP filters right into the ADE-1 diode ring mixer. I have the TIA amps set at about 24 dbm. There is a lot of audio gain from the LM386 and the audio pre-amp. This seems to be enough, even on 20. I hear the band noise when I connect the antenna on both 75 and 20.
Here is the first video in the series. I’m posting them first on Patreon, then, a few days later, here and on the YouTube channel.
Bravo Zulu Bill! Nice project and the results so far are stunning. 73’s Pete