Panadapter

Project Completed: Feburary 24, 2022

Raspberry Pi + RTL-SDR Panadapter

I put together a panadapter for my TS-480 using a Raspberry Pi and an RTL-SDR software defined radio USB dongle. The software I used to make the waterfall is called GQRX, a linux based SDR program. If you turn off the sound decoding, the waterfall can go a lot faster and at a higher sampling rate. To make the program start right when you apply power, I wrote a script that emulated keystrokes to automatically click the required buttons to start the program. This is a dirty way to do this, but the program does not have a CLI-friendy option. The radio had a couple of very convenient IF pins inside, so I used a female jumper wire and soldered the other end to a coax with an SMA connector on the other end, which then plugs into the RTL-SDR.

The frequency that the SDR tunes to depends on what the IF frequency of your particular radio is. My TS-480 has an intermediate frequency of 73.095MHz. As you tune the knob on the radio, the water fall moves without any interaction with the SDR program itself. I had trouble with latency on the waterfall, so I just played with the settings and found a nice balance between sampling rate and performance. (More samples means more delay). This is primarily because of how weak the Raspberry Pi processor is.

I made this a year ago, so my memory of what settings I used and why I did some things is a bit fuzzy, but with a little experimentation, you should have no problem getting it to work. There is plenty of info online as well in case you run into trouble replicating what I did here.