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Re: #17m #vfo #troubleshoot #qcxmini #17m #vfo #troubleshoot #qcxmini

Ronald Taylor
 

Hi Paul. The first thing I would suggest is to change power supplies to verify you aren't getting the growl from that source. Even a 9 volt battery will power up the Mini for this test. Some power supplies are more noisy than others. 

If it's still growling on battery, you might perform a factory reset... after first noting the Reference frequency (8.5) and the System frequency (8.6) as these will need to be reset, along with resetting the band after a factory reset.

Good luck ... 73 ... Ron

On Thu, Mar 3, 2022 at 12:29 AM Paul Cooper <nemo0@...> wrote:
Hans et al.

Having operated the QCX-mini 45 days or so (at the correct txco ref. freq., eliminating that variable - thanks, Hans)  I have surely discovered what all the fuss is about with this little rig.  It's so quiet that one might mistake it for being "deaf" side by side with 7410.  Impressive!

However, something has been quite wrong with my particular unit from the start.  The "idling engine" and "growl" obscure all but the strongest of signals, even when a couple kHz off.  The "growl" is strong only in a handful of places, but that's enough to almost wreck the whole experience.  And, if one listens very carefully, the "growl" can be heard across the entire band, though at a level that would be negligible if that were only that, but it's not.

Following are the spots where the "growl" is a constant and unavoidable:  

68-72 kHz  almost imperceptible to low level loping "growl" (this is the only part of the spectrum where it lopes)
73-74 kHz  low level "growl"
75.5-76 kHz low level "growl"
78.5-79.5 kHz extremely low level "growl"
84.5-86.5 kHz very loud "growl"
87-88.5 kHz loud "grow"
101-102.5 kHz very loud "growl" (this "growl" is exceptional as it shifts downward to 100 kHz intermittently; can change by restarting unit)
110-112 kHz extremely loud "growl" (by far the highest level over the band spread)
113-114 kHz loud "growl"
136.5 kHz low level "growl"
152.5 kHz moderate level "buzz/hash" (outside cw segment so not an issue)
159 kHz extremely low level "growl"
162 kHz low level "growl"
164-165 low level "growl"

Note:  The "growl" is at high levels for brief intervals when toggling the VFO and going from menu selections back to the on-air status.  Also, the "growl" is continuous, at a medium level, across the entire spectrum when the RIT is turned on.

I purchased this unit pre-built as I don't have much time to troubleshoot, etc. here, so I'm afraid that I can mostly offer you the symptoms.  What are we looking at here?  My guess is something to do with grounding of a circuit but I really don't know.  Any help would be much appreciated.  Thank you.

73,

Paul
V7/KA4WPX

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