Question about radio connections

[Happy_Hamer]

After reading a topic on here about connecting the radio backwards I have a question.

I know this is a CB section but I am betting it could happen on any radio,,,,

I was talking on a 2 meter repeater.

The other guy had a buzzzzzzz in his audio. I told him about it and he pulled his car over to check it out. The radio is remote mounted with the head unit up front near the driver and the radio itself was mounted in the rear, he drives an HHR.

He went to the back and noticed the ground wire was disconnected and just hanging in the air not touching anything.

How was the radio still able to work?

Once he fixed the ground and made the connection the buzz was gone in his audio.

We both ASSumed the ground was coming from the antenna mount which kept the radio working?

Just weird and wanted thoughts from others what may have kept it running

 

[Captain Kilowatt]

It could have been using the coax shield as a ground or it may have been getting ground through the fact that the radio chassis was bolted to the car chassis in the trunk.If the coax was the ground path then the ground would have had LOTS of RF on it and that could be the cause.I had that happen once to a radio.It was turned on and when I unhooked the coax it went dead and a spark came from the end of the PL-259 shell. :shock: That caused me to think for a moment. :? The ground wire had rotted off.

 

[ken white]

I'm agree with QRN. If the antenna ground was bad, then the coax was providing the RF ground and the chassis ground was now seeing a lot of localized RF which probably caused the hum.

 

[C2]

I've done that before. I had a solid antenna mount and I brought the radio out and set it on the seat.

I attached the coax to the radio and just the positive supply, and the radio went on, grounding through the coax shield.

 

[C W Morse]

And sometimes you will know something is amiss even if the radio is otherwise working. It's when you start getting "bit" when your mouth brushes the mike (OUCH! ) or you just barely contact the chassis and you wonder, "did that thing just shock me"? It is also when the ground(s) become "resonant" from a long path to ground. That's why it is important to ground the set instead of hastily plopping the radio in and screwing in an antenna. As an aside, the IC706 is notorious for the famous "screw-left-out-of-the-remote-cable- thing-a similar problem encountered by hams.

73

CWM

 

[Happy_Hamer]

This was the infamous Icom IC-2720.

And sometimes you will know something is amiss even if the radio is otherwise working. It's when you start getting "bit" when your mouth brushes the mike (OUCH! ) or you just barely contact the chassis and you wonder, "did that thing just shock me"? It is also when the ground(s) become "resonant" from a long path to ground. That's why it is important to ground the set instead of hastily plopping the radio in and screwing in an antenna. As an aside, the IC706 is notorious for the famous "screw-left-out-of-the-remote-cable- thing-a similar problem encountered by hams.

73

CWM

 

[Moleculo]

Hamer, you know "that person with the buzz" was really you...don't try and fool us

BTW, my 2720H just crapped out...no power output. I accidentally keyed it a few too many times with no load...I had the coax hooked up to a different radio and forgot. Oh well...

 

[FredInFl]

A Buzz

BTW, my 2720H just crapped out...no power output. I accidentally keyed it a few too many times with no load...I had the coax hooked up to a different radio and forgot. Oh well...

And who was the 1 with a BUZZ?

 

[Happy_Hamer]

Re: A Buzz

BTW, my 2720H just crapped out...no power output. I accidentally keyed it a few too many times with no load...I had the coax hooked up to a different radio and forgot. Oh well...

And who was the 1 with a BUZZ?

HAHAHAHAHAHAHAHAHAHA