[Elecraft] (OT) Recommendations for Testing

[Geoffrey Mackenzie-Kennedy]

Ed,

A very important consideration when measuring the IMD performance of an 
amplifier (or certainly a receiver), is that the level of any 
intermodulation products generated by the test equipment must be low enough 
so that they do not introduce measurement error.   Among the usual sources 
of these rogue IMD products are the spectrum analyzer (for sure if is 
overdriven), the combiner used to combine the two test tones, and the 
harmonics generated by the two test tone sources - all of which can be 
muzzled.

Of course the better the IMD performance of the DUT, the more significant is 
the the error introduced by any test equipment generated products.

If you will bear with me (it is late here), and if of any interest to you, I 
can send you off list later today more detailed information.

73,

Geoff
LX2AO


On March 17, 2012 at 20:19 +0100, Edward R. Cole wrote:


>I will be testing some amplifiers, soon, and would like advice or
> links to info on making IMD and harmonic level tests on HF amplifiers.
>
> I can generate two-tone modulation and monitor spectrum up to 196 KHz
> width with my SDR-IQ, but do not have a spectrum analyzer.  I have a
> scope, power meters, 500w coaxial load, XG3, and a couple DMM, plus
> analog 30v and 30a dc meters..
>
>
> 73, Ed - KL7UW, WD2XSH/45