Spectrum Analysis for Beginners

Talk about other SDR products like the FunCube, HackRF, BladeRF etc.
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Joined: Mon May 17, 2021 9:24 am

Spectrum Analysis for Beginners

Post by praxis » Mon May 17, 2021 9:53 am


New user here. My end goal is to determine what intermittent WiFi and Bluetooth signals are causing interference for our local Bluetooth devices. So, basically spectrum analysis on 2.4ghz/5.0ghz as I understand it. From what I've been able to determine so far:

-- General WiFi scanners and stuff used for wardriving only report SSIDs and won't show interference from microwaves, other Bluetooth devices, cordless phones, etc.

-- There are some Bluetooth scanners, but again like WiFi, they only watch for their own type of devices.

-- There are WiFi scanners that will show interference - for example, Wi-Spy/etc from Metageek - but they're big bucks.

So the trick becomes microwaves, etc...

Thus I finally came across SDRs (which, btw, is incredibly hard to find when searching typical terms like wifi interference scanners, etc - Googled "wardriving spectrum analysis" to get here).

So there are a few USB connectable SDRs available, like rtl-sdr, HackRF, AirSpy, and there is software that'll interface and display the radio waves that they see.

As I understand it, I wouldn't see any SSIDs, indication of device type, etc. - we're basically down around 0 or 1 on the OSI stack here, right?

Lastly, I looked at the frequency ranges of the SDRs and it seems that really only HackRF would work for WiFi/Bluetooth, so I'm thinking of pursuing that and finding the right software.

Please let me know if I'm off base on any of the above, or if I should stay the course with HackRF/software. If so, any names of software or other tips would be appreciated. For example, I'm curious next how I could potentially read SSIDs and device-level info, once I complete the above - just for the heck of it :)

Thanks all, much appreciated,


Posts: 107
Joined: Wed Apr 25, 2018 8:14 am

Re: Spectrum Analysis for Beginners

Post by aurgathor » Sun May 23, 2021 8:43 am

Cheap SDRs won't go to 2.4 GHz, but you can use a number of downconverters.

In addition, there are a number of SDRs capable of 2.4+ GHz.
1. HackRF
2. LimeSDR
3. Adalm Pluto

Posts: 253
Joined: Tue Dec 27, 2016 11:00 pm

Re: Spectrum Analysis for Beginners

Post by snn47 » Thu May 27, 2021 8:56 pm

Why would you want to looke into 5 GHz WLAN, when Bluetooth is in the ISM bands, from 2.402 GHz to 2.48 GHz.
Since you wrote intermittent, it could be also other devices besides Bluetooth or WLAN, e.g. microwave oven that also work in this ISM-band at ~2.4 GHz.

If you read a few post down viewtopic.php?f=4&t=6202 you find more information on SDR use as SA.

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