[RFI] USB Spectrum Analyzer

David Robbins k1ttt at verizon.net
Thu Sep 25 13:20:36 EDT 2014

I have used the sdr-iq receiver (http://www.rfspace.com/RFSPACE/SDR-IQ.html) for rfi and analysis of grow lamp noise.  it only goes to about 190khz bandwidth but is quite usable and has a wide range of pre-amp and attenuator settings built in.  it also doesn't require any external power, just the usb power which makes it handy to use with a laptop.  see some of my spectrum screen shots at: http://wiki.k1ttt.net/(X(1)S(qfsrcu55xitt4n45g2sitifz))/2012%20Maintenance%20and%20Upgrade%20Blog.ashx#160mrfi   (keep scrolling to the end of the page as some other stuff is intermixed).



Sep 25, 2014 01:09:54 PM, mstangelo at comcast.net wrote:

If you're interested in this Spectrum Analyzer you can check a review on Kenneth Wyatt's EDN Blog:

While interesting he prefered TTI or Rigol Spectrun Analysers.

Ken is an EMC Consultant who has excellent as well a practical application notes and reviews on the blog as well as his website:

Here is his report on a visit to ARRL Headquarters. Note that they discuss interference from the grow lights:

If you want to experiment with a USB Spectrum Analyzer I'd get one of these $20 DVB-T USB receiver sticks:

and use it with the free evaluation version of Touchstone software:

The DVB-T doesn't cover HF, the rtl2832 starts at 24Mhx, but the price is right.

There is lot's of good information on Ken's site.

Mike N2MS

----- Original Message -----
From: Paul Christensen 
To: RFI Mailing List 

Sent: Thu, 25 Sep 2014 12:41:16 -0000 (UTC)
Subject: Re: [RFI] USB Spectrum Analyzer


I think -110 dBm sensitivity is marginal for RFI detective work, especially 
while working with low gain loops when trying to localize switch-mode 
interference. Some of the loop preamps I've used produce much more 
gain/noise than signal. For the money, I would look at one of the new, 
compact SDR receivers that contain a basic spectrum analyzer function. 
These will measure a -140 dBm noise floor. Of course, you don't have the 
ability to change resolution bandwidth as one would have with a true 
spectrum analyzer but that's perfectly adequate for RFI work.

Paul, W9AC

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