Ideas for a cheap 2.4 Ghz Spectrum analyzer / power level meter - Page 1
Forum section: electronics / rf-microwave

author: Purevector
author_rank: Contributor
timestamp: December 09, 2018, 06:42:48 pm
content: I'm working on a project that involves devices that communicate at 2.4 Ghz. As a post-production test, I need to check the Tx power level of each device, and the transmission frequency.Absolute values do not matter. I have a reference unit which I can use as a baseline and then just compare all other units to it.I am aware of the RF Explorer line of products, but I am wondering if there is anything cheaper, like a USB dongle or something similar.Thanks for everyones input. Cheers.

author: rhb
author_rank: Super Contributor
timestamp: December 09, 2018, 08:47:36 pm
content: I'm not aware of any low cost SDR or other instrument that goes high enough. The best alternative at low cost that I can think of would be to build a downconvertor and then feed the output to an 8-12 bit SDR.There are other options such as building a power meter, but rather a lot more work than buying an oscillator and mixer from MinCircuits and an 8 or 12 bit SDR.

author: Bicurico
author_rank: Super Contributor
timestamp: December 09, 2018, 10:09:51 pm
content: Hi,Take a lok at my blog:https://vma-satellite.blogspot.com/2016/12/vma-simple-spectrum-analyser-download.htmlDownload the manual.Regards,Vitor

author: Purevector
author_rank: Contributor
timestamp: December 11, 2018, 05:05:30 pm
content: Thanks for the tip, Bicurico. It turns out I need a much better RBW than the cheap ADF4350 based units can provide.I think the 2.4 GHz RF Explorer is in fact my best bet for this particular application.But I did learn quite a bit from your blog and videos, thanks!

author: 9aplus
author_rank: Regular Contributor
timestamp: December 11, 2018, 06:27:32 pm
content: Lime SDR mini goes up-thereLimeSDR mini has a frequency range of 10 MHz – 3.5 GHz

author: Bicurico
author_rank: Super Contributor
timestamp: December 15, 2018, 02:26:44 pm
content: Perhaps look at the HackRF. There is a pretty neat spectrum analyzer software for it, though it does crash a lot (the HackRF not the software).I wonder if the RF Explorer has a better RBW than the ADF4350 based devices...Regards,Vitor

author: Purevector
author_rank: Contributor
timestamp: December 16, 2018, 10:54:58 pm
content: I got the RF Explorer 2.4G. It's a nice little unit and allows for quick and easy measurements. Worth the money I'd say. The RBW can be as fine as 50 kHz, so that's great for me.Cheers.

author: Purevector
author_rank: Contributor
timestamp: December 17, 2018, 09:07:53 pm
content: Quote from: Bicurico on December 15, 2018, 02:26:44 pmNot that it matters much now that I have an RF Explorer, but I am confused about the RBW of the ADF units. In some places I read it's 1MHz, and other posts say 100kHz. Do you know which spec is correct?

author: MF-jockey
author_rank: Regular Contributor
timestamp: October 15, 2020, 09:39:04 am
content: RF Explorer comparison chart document in PDF:http://j3.rf-explorer.com/images/stories/RFExplorer/RFExplorer_ModelsTable.pdfhttp://j3.rf-explorer.com/menu-models

author: Bicurico
author_rank: Super Contributor
timestamp: October 16, 2020, 08:29:58 am
content: While I don't really know the specs of the ADF4350/4351, from my experience you get a resolution of around 100kHz, which is plagued by the "notch". With around 1MHz you won't see this "notch", which probably explains why some say 100kHz and others 1MHz.Regards,Vitor

author: David Hess
author_rank: Super Contributor
timestamp: October 16, 2020, 02:05:57 pm
content: If a direct instead of field strength measurement is possible, then some frequency counters also indicate power level.I would also consider buying a suitable frequency counter, and building a separate RF probe to measure power level.

author: tmbinc
author_rank: Frequent Contributor
timestamp: October 19, 2020, 10:56:42 am
content: Most modern WiFi chipsets support capturing raw ADC data, and transmitting arbitrary data, and have high bandwidth (though generally poor linearity/IQ balance etc.). Unfortunately, it's mostly hidden away behind undocumented register sets or API.https://github.com/seemoo-lab/mobisys2018_nexmon_software_defined_radiofor example implements this, but it's TX-only.I was once told that a specific router can display a 2.4GHz spectrum using this mode, but I forgot which one. Would be a fun project to build a very cheap 2.4GHz realtime spectrum analyzer...