Re: Swapping Nano's
To answer your second question first, yes you can use a second Nano to program and keep the first as originally received. There are issues that need to be taken into consideration.
1 - The calibration data is stored on the eeprom of the Nano, which is not saved in the CEC software. You will need to calibrate before it will work correctly, especially the BFO setting.
2 - The CEC software is different for each display, and the original software only works with the original display. That would mean that you need to change the Nano AND the display if you do not use the original display version of the CEC software
The first question depends on what you want for a display? I have the 3.2" that Dr Lee had already created a full screen tft file with the link from the web page. That is what I would use. This is a personal choice. If you want bigger, then you will need to find the correct tft file to match your display. 2.4 and 3.2 I believe are the two that Dr. Lee has programmed.
You do not need to compile the code if you use the correct hex file. Use the uBITXV5 directory and read the FileNameInfo.txt file to help select the correct hex file to load into the Nano. You will need the Hexloader program to go that route. I believe that this is where I got the version that worked for me:
Incase you did not get it, here is the link to the Git Hub repository zip file:
This should get you started.
For the calibration process, I would do a search on this site to learn the how to do it. NOTE that the CEC software does not use the same method as the stock (it does not turn on the transmitter to zerobeat wit another receiver. For the CEC firmware I would download the Memory Manager that Dr. Lee has created to make the adjustments and save the values after a change to be able to backtrack if something goes wrong.
For the BFO calibration I prefer to use a PC based free audio spectrum analyzer that can be downloaded from here:
I connected a mic to the input of my PC, tuned the uBITX to an open frequency with just static, and adjusted the BFO to center the noise spectra between 500 and 2500 Hz. I then went back and re-calibrated the maser clock, then back to the BFO for a final time.
The above is what worked for me. I cannot guarantee that it will for everyone. I would suggest that you do the search on this sit as stated above.
The above is free advice; it is worth only what you can make of it, and should be checked as well as you can.
Use at your own risk.