----- Original Message -----
From: "Joe Subich, W4TV" <w4tv@subich.com>
To: <garyschafer@comcast.net>; <amps@contesting.com>
>> Even if there is some receiver IM generated it only needs to
>> be a few db below what we are looking for to be masked.
>
> However, absent AGC to prevent overload, the dynamic range of
> many IF strips (particularly where the primary filtering is
> provided by DSP) is less than 30 or 40 dB. If you are looking
> at - 35 dB 3rd order and - 40 dB 5th order, that is pushing the
> real dynamic range of the IF.
>
>> By the way most spectrum analyzers have filters with a rather
>> broad shape factor compared to our receivers and seem to do
>> just fine.
>
> Most spectrum analyzers have much better IF strips (and fewer
> conversions) that the typical amateur receiver. They are
> optimized for dynamic range and not selectivity ... they have
> to be.
>
> 73,
Sounds like the Flex Radio SDR-1000 would be ideally suited
for this task. It has very a simple conversion scheme, high
dynamic-range, and no analog AGC (either derived or applied).
With a 44 KHz sampling rate sound card it should easily provide
15 to 20 KHz of useable spectrum viewing with good dynamic
range.
73, Mike W4EF...........................................................
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