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moble/base odd behavior in the car..

KD2GOE

W9WDX Amateur Radio Club Member
May 30, 2013
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Buffalo
I am Running a KL203 in my car with a Cobra 29 and tested it with my uniden Washington. When plugged in to the cobra 29 my meter light goes out.. and when plugged in to my uniden Washington it just jumps in to TX even with out the mic plugged in ..

I narrowed it down to when the "negative ground" is applied to the chassis of the radio through the coax it is giving this behavior and has nothing to do with the amp other then it passing the negative to the radio chassis . I can even just take the negative and touch it the steel frame and it will do this.. I know the radios have a floating ground system but how to you guys over come this when putting in an amp.

I am hopping to get a cobra 148 or uniden 980 down the road and I don't want it to give me trouble like this...

Thanks for any help
Matthew
 
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a buddy of mone was having a problem about like you described and the little amp was the problem. he also had the 203 rm amp and found the relay was bad and a couple of the rm trans were bad. . changed them all out and it worked fine.
 
a buddy of mone was having a problem about like you described and the little amp was the problem. he also had the 203 rm amp and found the relay was bad and a couple of the rm trans were bad. . changed them all out and it worked fine.

Hmmm ill take a look at the relays and tap them spray some cleanner in there ...

I can make the 2 radios do the same thing even with out the amp, if I apply the negative to the frame of the radio so I did not think it was the amp
 
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ok the amp is not at falt it is the radios. Even with out the amp they are doing it... and they only do it in the car... when i get my new radio ill just hope it dont do the same thing..
 
A floating ground is a characteristic of some electrical circuits. Every electrical circuit has a ground point, which often serves as a return path for electric current. Usually this point is electrically connected to the Earth, hence the name "ground". The ground is said to be floating when this connection does not exist.
:unsure:
 
I experienced a so called floating ground issue with my K40 magmount antenna I used to have on my car several months ago. My swr readings would never stay the same. I finally called K40 to explain the issue I was having to them. K40 replied that with their magmount antennas,I needed to ground my radio's case to vehicle ground. My Galaxy DX-959 I was using in the car at the time has two different ground potentials between the ground wire at the back of the radio and the radio case in which the SO-239 connector is mounted to.
I grounded the radio's case to vehicle ground,the same place I grounded it's ground wire. That stopped the issue of constantly changing swr readings I was having.
 
Check your radio power ground or run your power straight from your battery

the power it right from the battery the negtive is right from the fire wall with a bolt.


what vehicle?

2007 impala

You may need to lengthen your jumper between radio & amp.

its not the amp it will do it with out the amp.






Floating ground?

The negtive in most moble radios have what is a floating ground/negative if you put a meter on the nevtive to the frame of the radio there will be no continuity. because it is isolated with a bunch of caps.

What antenna system are you running?

Wilson 1000 roof top mount mounted to my trunk lid.



i tryed my frends Cobra 29 and it works fine so it has to be some thing odd with my 2 radios.... :thumbdown:
 
The negtive in most moble radios have what is a floating ground/negative if you put a meter on the nevtive to the frame of the radio there will be no continuity. because it is isolated with a bunch of caps.
:

Is incorrect.
 

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