I had a couple of other replies off list that confirmed that this is perfectly
normal, and usually band noise covers these spurs up.
Apparently they are from the high efficiency switching voltage regulators on
the 5V and 3.3V lines in the PX3. I suspected that, but though mine was perhaps
If you have the PX3 completely unplugged do you see those spike at 12KHz
spacing? They are very prominent then.
Tried the following:
REF level -145
SCALE 80
SPAN 50
Everything plugged in apart from the RX I/Q lead at the PX3 end:
Noise floor about -138dBm
2 spikes either side either side of
Make sure your cables are well seated. I believe I
got that symptom one time when one cable was not
fully plugged in.
73, Phil W7OX
On 2/4/15 3:11 PM, David Anderson wrote:
I notice I have large spikes every 12kHz at about -115 dBm whether connected to
the KX3 or not.
Thought it may be by
I notice I have large spikes every 12kHz at about -115 dBm whether connected to
the KX3 or not.
Thought it may be by switching PSU I was testing with, but tried a silent
linear PSU with the same result. Is this normal or have I a problem with the PS
board in the PX3?
73
David Anderson GM4JJJ
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