[KX3] Can someone help explain this - AM/LSB/CW Freq

[Gary Hawkins]

I was playing around with an RigExperts AA-54 antenna analyzer today
using it as a signal source for the KX3.  I fed the AA-54 into a Alex
Loop inside the house and had the KX3 connected to my mini-G5RV
outside.  I set the AA-54 to do continuous spot measurements at approx
14.082MHz.  In this mode the AA-54 excites briefly approx once per
second at the chosen frequency.

Using HDSDR connected to the I/Q output of the KX3 via computer in CW
mode I observed a pulsing signal peak at 14,081,530Hz.  In LSB mode I
observe the signal peak 14,082,127Hz.  In AM mode I observe the pulsing
peak on HDSDR at 14,071,114Hz.  I get the difference between the first
two measurements (600Hz side-tone), I don't understand the results for
AM display.

Now if I tune the KX3 manually and listen for the signal I get the
following, LSB strong S9 1KHz pulsing tone at approx 14,082,600, CW
strong pulsing tone S9 zero-beating tone at 14,082,108 and finally AM
weak peak (S2) pulse at approx.14,081,800Hz.  These measurements make
more sense but don't explain what I'm seeing using HDSDR monitoring AM
obtained from KX3 I/Q.

Any thoughts on what I'm seeing, particularly regarding AM?

73's Gary K6YOA
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[Greg Troxel-2]

Gary Hawkins <[hidden email]> writes:

> Using HDSDR connected to the I/Q output of the KX3 via computer in CW
> mode I observed a pulsing signal peak at 14,081,530Hz.  In LSB mode I
> observe the signal peak 14,082,127Hz.  In AM mode I observe the
> pulsing peak on HDSDR at 14,071,114Hz.  I get the difference between
> the first two measurements (600Hz side-tone), I don't understand the
> results for AM display.

I'm fuzzy on the details, but The KX3 can function either as a zero-IF
receiver or essentially as a more or less 8 kHZ IF, which can trade some
problems for others.

My theory is that in your setup, with AM the IF is moved, and your external
decoded didn't get the memo.

73 de n1dam
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