[Elecraft] dynamic range questions

[Geoffrey Mackenzie-Kennedy]

Yes I agree, but not all up-conversion radios suffer from this problem. It 
is a great pity that the design of amateur up-conversion radios do not seem 
to include very strong IF amplifiers IIP3 in the +45dbm region, which allows 
for some relaxation in roofing filter requirements , cost I suspect. Far 
fewer close in spurious responses to deal with.

Geoff
GM4ESD

Bill W5WVO <w5wvo at cybermesa.net> wrote:

> Well... yeah,sure. That's why the K3 offers a selection of appropriately 
> narrow roofing filters at the 1st IF frequency. If you're trying to copy 
> CW with the 6 kHz AM filter inline, of course you're going to have 
> problems, just as you certainly do with all the up-conversion radios (like 
> the TS-2000 I own) with broad-as-a-barn-door roofing filters in the 1st 
> IF. Strong off-frequency signals within that wide passband will cause 
> later stages to fall apart, no question. That's why the K3 (and a few 
> other radios like the Orions) are designed the way they are -- to do 
> everything possible to mitigate against that possibility.
>
> Bill / W5WVO