Author Topic: Bah! "Hum" Bug!!  (Read 520 times)

w6aso

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Bah! "Hum" Bug!!
« on: 2016-12-14, 20:54:07 »
I have gotten everything working with the remotrig, except for one thing....There is a "hum" that limits the amount of audio gain I can use.   I have checked everything for ground loops, etc, but haven't stumbled on the cause.   I do notice that there is no direct  ground connection between the circuit board ground and the chassis or case.  Would there be any contraindication to adding a short ground wire between the circuit board and case to reduce the chance of a ground loop? 
I have added an audio isolation xformer between the microphone and the input which has helped some but not enough  to eliminate the hum.  What about adjustment of the audio "codec" gain or attenuation?  Not sure I totally understand these adjustments to vary them from the default values. Suspect the "boxes" could be set to sensitive?
Thanks,
Chuck, W6ASO



 
 

dj0qn

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Re: Bah! "Hum" Bug!!
« Reply #1 on: 2016-12-14, 21:04:57 »
Chuck, what kind of radio are you using?

73,
Mitch DJ0QN / K7DX

w6aso

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Re: Bah! "Hum" Bug!!
« Reply #2 on: 2016-12-15, 03:20:27 »
I am using the TenTec Orion as I have indicated in other posts.  As I indicated all functions are working with the remote rig except for the sensitivity of the audio being subject to hum if I turn up the audio to get enough drive out  of the transceiver.

Thanks,   73

Chuck, W6ASO   

dj0qn

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Re: Bah! "Hum" Bug!!
« Reply #3 on: 2016-12-15, 04:43:45 »
I don't see any other posts in this thread.

Your problem is not likely caused by a problem with the RRC, nor are there any RRC settings that can help
it as you suggested. The most common cause of hum has been running the 12v to both the radio and
RRC from the same PS or plug. If you have done that, then separate them onto separate power supplies
and possibly separate AC plugs/strips.

If that doesn't solve the problem, I can highly recommend the guides written by Jim, K9YC at
http://audiosystemsgroup.com/publish.htm

73,
Mitch DJ0QN / K7DX