Spectrum analysers

I’ve been looking for some time for an affordable (i.e. used) and useful ranged (i.e. not cheap!) spectrum analyser. Obviously I want DC to light but don’t need it and don’t want to sell the house for a bit of test gear. I have a TinySA which is good to 960MHz but I will need a higher frequency range as I fiddle more with microwaves.

The ultimate, e.g. a Rigol or Siglent LCD type device is just far too expensive. Nice to have yes but something one would need to be using all the time in order to justify it. Then I came across Satsagen – http://www.albfer.com/en/2020/02/21/satsagen-2/

Satsagen runs under Windows and by default uses an Adalm Pluto as its interface to the real world. The software even does the necessary to upgrade the Pluto to the ‘full’ range of 70MHz to 6GHz (you can do this easily by hand but it’s nice of the software to do it anyway). The software has three basic function too – spectrum analyser, spectrum analyser with tracking, and generator. So, one PC, one Pluto, Satsagen and you get a pretty decent 70MHz to 6GHz spectrum analyser, tracking generator and signal generator.

I have not yet delved into all the functionality and only carried out a couple of quick tests on a handheld and on my 70MHz transverter, plus a very quick test of a FPV transmitter (TS832) up at 5.6GHz.

It will work with other devices such as the HackRF and the RTL dongle but it seems so useful I purchased a Pluto just for it (yeah, ok, I can use it for other stuff too but hey)

PiBox progress…

The PiBox is almost completed. It’s taken far too long due to all sorts of silly things like having to get fans because a dry run indicated the poor little boards were getting a bit hot, having to get bolts for the fans because I had none long enough, and having to get a connector for the 1-wire (actually 3 wires!) lead from the central heating sensors.

So, there is is. Two fans on the left, 5V PSU bottom right, gigabit Ethernet switch above that, then the Pi’s: top is the PiStar with the DVMega board which has coax to the rear panel and then a dummy load, middle is the ASD-B and central heating monitor Pi, and the bottom is a general purpose one with various bits on such as rtl_tcp. The lower two boards have USB-A sockets on the rear of the case for the two SDR sticks, one for the ADS-B antenna and one to attach to a Discone for general use.

But there is an issue. I had originally intended this to sit in the shack but those fans are just too annoying. Not loud, but constant. I suspect the box will end up in the loft. Or maybe a re-think. I may fiddle with running the fans from one (or two) of the Pi’s and set up some temperature control to turn them on and off. It may even be that I am rather too ‘sensitive’ to the temperature range as others seem happy running their boards a lot hotter than I do mine.



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