Ben K8DIT <benk8dit@serv.net> wrote:
> Not there.
Generally, the swept tests have only been performed on
high end rigs, with a couple of noteable exceptions
(I did the IC-706 and FT-100 rigs because the 706 was
done in Mar 96 before I became the Test Engineer.
So, no swept tests were done on the Pegasus or Jupiter.
> We are lead to believe that the swept BDR and IMD
> are half that of the Main Rx on the Orion! There
> must be a 'rest of the story' there.
There is indeed. Although the 1 kHz data is not
inside the IF filter on the K2 or the Orion, this
data *is* inside the first IF filter for rigs with a
high first IF that lack narrow filters. The Jupiter,
Pegasus and Orion sub receiver all fit this description.
Note that this discussion only applies to performance
at close-in spacings - at wider spacings outside the
filter, the disparity isn't so severe - but there is
certainly still a disparity.
> Also, there is a move by some to increase the IF gain by
> turning an internal pot in the Jupiter. This cant be a
> good thing for BDR and IMD readings but no one is
> postulating on its negative potential.
Well, as I can tell you from tests I've done on a number of
FT-1000MPs, adjusting the IF gain does indeed impact the
dynamic range. However, modest adjustments will only
change the results by a few dB.
It is also worth noting that not everyone needs the kind of
DR performance that Bill does. :)
73, Michael, KC1SX
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