Is anyone using the SDR-14 for IMD measurements? I bought one last
year for just that purpose but ended up using it as a receiver instead.
I want to buy another one to use for bench work. Unfortunately I just got
taken by an SA dealer on ebay for 1500 so I wont look there again.
The SDR-14 certainly looks promising for a FFT based IMD analyzer.
Mike k1ern
----- Original Message -----
From: "Martin AA6E" <aa6e@ewing.homedns.org>
To: <amps@contesting.com>
Sent: Friday, August 11, 2006 10:43 AM
Subject: Re: [Amps] Checking for IMD
> Bill,
>
> I've wondered about this, too. The lab method is to use a high-priced
> spectrum analyzer, but couldn't you do something useful with a soundcard
> based spectrum analyzer? You would need to have a linear detector and a
> two-tone audio source. This would be similar to the IMD measurement you
> get with a PSK31 monitor. The trouble is you need pretty good dynamic
> range to measure a healthy system.
>
> You could check the boxes being sold by www.cleanrf.com as described in
> the latest CQ. They let you look at "linearity" on a scope. My take is
> that you will only catch gross non-linearity (overdrive), but you
> wouldn't get quantitative IMD numbers with this approach.
>
> 73 Martin AA6E
>
> Bill Turner wrote:
>> Is there a simple procedure one can use for checking the IMD of an
>> amplifier? Frankly, it's something I have never tested myself, instead
>> just keeping the amp tuned correctly and underdriving when using SSB.
>> I've never gotten any complaints of splatter so I think it's under
>> control. Since I do mostly RTTY and some CW it has not been an issue
>> but I would like to be able to check it.
>>
>> Any recommended reading on the issue?
>>
>> Bill, W6WRT
>> _______________________________________________
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