Hi to all on the reflector. I'd like to put something out here and see
if others experience the same thing or if I possibly have a problem with
my K2 sn5834. Someone (I don't remember who) mentioned that a great way
to test receive sensitivity is to simply check for an increase in noise
level when switching from a dummy load to a resonant antenna on a dead
band (like 10m is lately), and I am a great believer in that method. I
have used it for years with various commercial and homebrew rigs.
So here's the deal. K2 set for 10 meters, preamp off, antenna is
resonant wire (and also used a beam). When switching between dummy load
and antenna, there is no (or barely perceptible) change in receiver
noise output. With the preamp on, the change is noticeable, as the
noise increases both with dummy load and antenna connected. What I'm
concerned about is the preamp off situation, as all other receivers I
have tested do show a marked change in receiver noise when doing this test.
I have already set the agc threshold so that there is no reduction in
band noise when turning agc on and off. Band pass filter alignment was
done with a minimum signal from a signal generator and IF and filter
alignments were done with Spectrogram and everything seemed to check
out OK. BTW, the I used two antennas for this test, a 3 el tribander at
40 ft and a OCF dipole cut for 160 and tuned with ATU.
Do others have the same or similar results with this test? I'd really
like to know if my K2 is behaving normally or I have a problem. BTW,
the results improve as you lower the frequency, but the first band that
shows a really marked increase in noise level with this test is 17m.
Any and all comments are appreciated.
73, Paul, N2PD
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