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Comment by arminiusreturns | Hacker News Reader

Do you have any suggestions on a good full duplex sdr to start with? The last one I remember wanting was maybe the lime something? ADS-B data is cool, but my main goal was/is to demonstrate use as a bug finder and maybe do some other spectrum fun with my pc accessories and tv, wlan, etc.

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Depends on how cost sensitive you are. Currently the LimeSDR[1] is the best value (even at $300 and no case) because it is not only full duplex, it also supports MIMO operation. While the latter is intended to support things like 4G LTE it also gives one the ability to do direction finding as multiple receivers clocked by a phase locked LO allows you to do phase analysis of incoming signals.

The Ettus USRP B-series[2] is very well supported for about $1000.

The ADALM-PLUTO[3] at $150 is a bargain for a full duplex SDR but a range of 325 MHz to 3.8GHz leaves a lot of interesting spectrum out. That is less of a problem if you get a mixer and RF signal generator because you can up/down convert the HF/VHF/UHF bands up to 1 GHz as an IF and play with them there. There are some off the shelf solutions for this like the 'Ham it Up'[4] but you are at the mercy of their TXCO.

I have all of these solutions except for the USRP and find that when I reach for a radio to look at a signal I usually grab the LimeSDR.

[1] https://www.crowdsupply.com/lime-micro/limesdr

[2] https://www.ettus.com/product-categories/usrp-bus-series/

[3] https://www.digikey.com/products/en?keywords=PLUTO

[4] https://www.nooelec.com/store/sdr/sdr-addons/ham-it-up-304/h...

Any recommendations for softwares to play around with?

I got a NooSDR (€30 ish on amazon). I agree so much that its 1090MHz(?) leaves so much to explore, but I didn't have much luck other than decoding TV/FM/DAB using CubicSDR, GQRX, and VLC.

I am more interested in using it with Python/GNU Radio so didn't bother installing those super cool web based tools yet. Since I'm just starting, I'd like to get a feel of using it with a general purpose "summary software" first. Essentially something that can lookup the frequency databases, etc. to tell me: what is it that I'm looking at; if its LSB/USB/FM, and these sorts of things. Overall, I quite enjoy CubicSDR for this, but I'd appreciate if you have suggestions or resources I could check out. Thanks for the info above!

I found gnuradio companion to be useful for just poking around. Assuming the radio has a gnuradio compatible driver then you can do a lot of basic things like tune it around various spectra and get a feel for its sensitivity and selectivity. You can try out lots of different things quickly with it.

Lately I've been looking at front end selectors and their impact on radio performance. I have been using pysignal to process snapshots of iq data from the radio in my test setup.

Thanks for the tip, this definitely narrows down problem space to poke around with.

Thank so much for taking the time to reply, very useful info.

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