Hi Bill,
A good informative site for practical two-tone based IMD measurement on ham
amplifiers is that of Larry W0QE...see his URL below:
http://www.w0qe.com/Technical_Topics/imd_testing_of_amplifiers.html
Other than that technique modern SDR based transceivers with a pan adapter
spectrum bandscope allows one to directly observe the occupied spectrum of
an on-air signal and confirm how narrow or otherwise the Tx frequency
occupancy is...and deduce the signal's IMD characteristics.
Leigh
VK5KLT
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Bill Turner
Sent: Saturday, 2 November 2013 3:01 PM
To: Amps
Subject: [Amps] Measuring IMD
In all my years as a ham I have never actually measured transmitter IMD
except for on-the-air requests for a "splatter" report. I'd like to do it a
little more scientifically.
I understand the concept of a two tone test but I'm wondering what is the
best equipment to make the analysis, short of mortgaging the house. The ARRL
handbook has a few paragraphs on the subject but is not very detailed.
Aside from buying a very expensive spectrum analyzer, is there a way for the
average ham to do it in his shack? Using a second receiver perhaps? I do
have a decent scope so is there some kind of adaptor that can be bought or
made?
I see Wavenode has a series of SWR/Wattmeters that look like they would do
the job so I wonder if anyone has used them and compared the results to the
more expensive equipment.
Thanks in advance,
73, Bill W6WRT
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