I opted for the Audio injector Ultra sound card instead.

I am thinking of doing something similar but using an SBC for the DSP processing. I have a Raspberry Pi 3B+, an Odroid XU4, and an Amlogic S905 board to test with. I have this sound card coming. https

Can't speak about all the Russians on eBay but after seeing some stuff there I ended up buying from https://www.rv3yf.store and got everything I expected to get. One thing to note. The filter kits I b

I like the idea of the resistor matrix. I might have copied it if I hadn't gone a different way already. This little board from Sparkfun can do up to an 8x8 matrix, has debounce built in, uses I2C, an

Congratulations. And I can do all that without learning to write and compile GUI programs under Windows or Linux? Or this RPI OS you mention? Also, I prefer wxWidgets so you should use that instead.

True but that wasn't the question. I'm sure your way works great for you though.

With the Nextion display you don't draw buttons in code. There is a program that you run that you use to design the screens that are shown on the display. Then you are just passing data back and forth

According to the documentation the 1st oscillator tunes from 45 to 75 MHz to receive 0 to 30 MHz. Since the oscillator is higher than the received frequency this inverts the sidebands. LSB becomes USB

On the rv3yf page there is a link to a manual for the Klopik radio. The schematic for the filter is the same. There are YouTube videos showing the radios in use. On Mon, Jan 15, 2018 at 05:51 pm, Arv

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The documentation says 700 to 2500. It is a 4 pole filter at just under 9 MHz.

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I have a Russian radio kit I haven't put together yet called the Druzhba-M. It has a crystal filter with varactor diodes that it uses to vary the bandwidth of the filter.

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