SDR Upgrade

[David Leiken]

I’m looking to upgrade my SDR hardware. I now use multiple V5 Nooelecs. Looking to try out the Airspy product. For SDRTrunk would you recommend the Airspy HF+ Discovery or Airspy R2?

[Eric F.]

This depends on what you're trying to hear, the frequencies in use.
To follow a trunk system you're talking about VHF and UHF, so HF anything would not be a good choice. (HF is great fun but not for SDRTrunk)
How wide is the system? What's the distance between the lowest and highest frequency in use?
If you're going to use multiple tuners for one system the RTL-SDR Blog tuner is a great value. It's worth every penny of the additional $10 over the cost of the cheapy units like Nooelec and no-name. Buy only through their authorized sellers found on their website. They have a whole page on identifying clones and counterfeits. If you're buying the green or gold one you are buying a fake. These offer 0 to 2 ppm accuracy versus about 80.
If you need more bandwidth and better performance and are willing to spend around $100 (US) the Airspy would be my recommendation. But there's certainly nothing wrong the SDR Play product line. The latter is good if you want HF in the same box. The Airspy HF+ Discovery for example goes up to 260MHz. HF performance is quite good. Meanwhile the RSP family covers from about as low as radio signals can possibly go up to 2GHz. Compare this to 1.7GHz for Airspy R2 and Mini.
Higher bit depth equals more dynamic range (greatly oversimplified but that's the main point and it's what you always want). Airspy is 12 bit while RSP is 14. However, Airspy oversamples and uses DSP to achieve 16bit-like performance.
So with the RTL-SDR you get only 3MHz wide at the very best, typically less, around 2.5 reliably. While Airspy offers 6 and 10MHz models as the RSP offers 10. A trunk system I monitor is less than 6MHz but more 3 so I can't hear it all with only a single RTL dongle. However, another system hear is nearly 10MHz wide, even the Airspy mini will not do.

[Eric F.]

There's details, RSPdx for example specs 14bit ADC, but that's only up to 6 MSPS (Mega samples per second). At over 9MSPS it runs at 8bit. The Airspy offers 12bit all the time, up to 20MSPS, which is then decimated to 10.
RSP bandpass and notch filters may be helpful. So there's a number of things to weigh. With higher dynamic range notch filters become less important.

Keep in mind SDRTrunk will move its center frequency around. If a trunk system control channel is in the middle of the frequency range you only need a tuner that covers half the range for reasonable usefulness. But if the highest and lowest are in use at the same time you will miss calls.

[Joshua M Clatney]

Do you know if I can use an Adalm Pluto SDR with Sdrtrunk? I can't seem to get it to work. It has 20mhz of bandwidth so will cover way more than the RTL dongles. Thanks 

Thanks,

Josh Clatney 

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From: sdrt...@googlegroups.com <sdrt...@googlegroups.com> on behalf of Eric F. <ericfer...@gmail.com>
Sent: Friday, June 16, 2023 11:28:16 AM
To: sdrtrunk <sdrt...@googlegroups.com>
Subject: Re: SDR Upgrade

 

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[dave38...@gmail.com]

Do you know if I can use an Adalm Pluto SDR with Sdrtrunk? I can't seem to get it to work.

sdrtrunk supports the following SDR dongles:

https://github.com/DSheirer/sdrtrunk/wiki/Tuners#:~:text=sdrtrunk%20supports%20the%20following%20SDR%20dongles%3A