You haven't heard much about my Hybrid Wireless rig lately as I have been busy "flattening the warts" and we now have a better product.
[I find that blog readers usually only get this far and then head off to other parts looking for items on new radios or new technology. You should at least scroll to the end and watch the short video as the radio now "barks up a storm" and signals seem to pop out of nowhere.]
Some of the issues were RF Feedback and noise issues along with a change in the bias circuitry. The $30 Amazon power supply I found later on had a noise issue. It was noticeable at low volume levels. I replaced that with a full wave bridge rectifier and now the screen voltage (and plate voltage on the receiver tubes) is 240VDC. The noise is gone.
I had to add some shielding around the steered 2N2222A, that is the Rx RF Amp and Tx Pre-Driver and 2N3053 Driver stage. I also swamped the input of the IRF510 with a 50 Ohm resistor. Now no more RF Feedback.
The biggest issue was the JF3HZB software! This was truly disappointing and on par with the hot looking woman who had nothing to say except focus on how good she looked. I simply could not create a suitable BFO frequency that worked on both receive and transmit. I had to offset the BFO by some 2kHz and that was obviously wrong. The transmitted signal sounded like crap. Plus, there was no easy way to calibrate the Si5351. I went back to the Arduino Nano and the ILI9341 display... it was Right On The Mark! I note that the JF3HZB embedded Si5351 Files, (Si5351.h and Si5351.cpp files) are not the ones from Jason Mildrum, NT7S.
The Nano system I reinstalled has Jason's Si5351 files... the result is a perfect fit. Using a Grayhill optical encoder, the tuning is smooth. The other bonus is I built in the capability to have an S Meter on the display.
A Return to the Digital VFO using the Arduino Nano
Shield over the 2N2222A and 2N3053 Driver. 50 Ohm Resistor on the IRF510 Board.
These changes have greatly improved the functionality and operation of the transceiver.
Them that know can make it go!
73's
Pete N6QW