Author Topic: Ideas for a cheap 2.4 Ghz Spectrum analyzer / power level meter  (Read 3630 times)

0 Members and 1 Guest are viewing this topic.

Offline PurevectorTopic starter

  • Contributor
  • Posts: 32
Ideas for a cheap 2.4 Ghz Spectrum analyzer / power level meter
« on: December 09, 2018, 06:42:48 pm »
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.
« Last Edit: December 09, 2018, 08:43:06 pm by Purevector »
 

Offline rhb

  • Super Contributor
  • ***
  • Posts: 3476
  • Country: us
Re: Cheap 2.4 Ghz Spectrum analyzer / power level meter
« Reply #1 on: December 09, 2018, 08:47:36 pm »
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.
 

Offline Bicurico

  • Super Contributor
  • ***
  • Posts: 1707
  • Country: pt
    • VMA's Satellite Blog
Re: Ideas for a cheap 2.4 Ghz Spectrum analyzer / power level meter
« Reply #2 on: December 09, 2018, 10:09:51 pm »
Hi,

Take a lok at my blog:

https://vma-satellite.blogspot.com/2016/12/vma-simple-spectrum-analyser-download.html

Download the manual.

Regards,
Vitor

Offline PurevectorTopic starter

  • Contributor
  • Posts: 32
Re: Ideas for a cheap 2.4 Ghz Spectrum analyzer / power level meter
« Reply #3 on: December 11, 2018, 05:05:30 pm »
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!
 

Offline 9aplus

  • Regular Contributor
  • *
  • Posts: 158
Re: Ideas for a cheap 2.4 Ghz Spectrum analyzer / power level meter
« Reply #4 on: December 11, 2018, 06:27:32 pm »
Lime SDR mini goes up-there
LimeSDR mini has a frequency range of 10 MHz – 3.5 GHz
 

Offline Bicurico

  • Super Contributor
  • ***
  • Posts: 1707
  • Country: pt
    • VMA's Satellite Blog
Re: Ideas for a cheap 2.4 Ghz Spectrum analyzer / power level meter
« Reply #5 on: December 15, 2018, 02:26:44 pm »
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

Offline PurevectorTopic starter

  • Contributor
  • Posts: 32
Re: Ideas for a cheap 2.4 Ghz Spectrum analyzer / power level meter
« Reply #6 on: December 16, 2018, 10:54:58 pm »
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.
 

Offline PurevectorTopic starter

  • Contributor
  • Posts: 32
Re: Ideas for a cheap 2.4 Ghz Spectrum analyzer / power level meter
« Reply #7 on: December 17, 2018, 09:07:53 pm »

I wonder if the RF Explorer has a better RBW than the ADF4350 based devices...


Not 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?
 

Offline MF-jockey

  • Contributor
  • Posts: 40
  • Country: de
« Last Edit: October 15, 2020, 09:41:14 am by MF-jockey »
 

Offline Bicurico

  • Super Contributor
  • ***
  • Posts: 1707
  • Country: pt
    • VMA's Satellite Blog
Re: Ideas for a cheap 2.4 Ghz Spectrum analyzer / power level meter
« Reply #9 on: October 16, 2020, 08:29:58 am »
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

Online David Hess

  • Super Contributor
  • ***
  • Posts: 16544
  • Country: us
  • DavidH
Re: Ideas for a cheap 2.4 Ghz Spectrum analyzer / power level meter
« Reply #10 on: October 16, 2020, 02:05:57 pm »
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.
 

Offline tmbinc

  • Regular Contributor
  • *
  • Posts: 249
Re: Ideas for a cheap 2.4 Ghz Spectrum analyzer / power level meter
« Reply #11 on: October 19, 2020, 10:56:42 am »
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_radio for 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...
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf