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UHF interference query 

 

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 Post subject: UHF interference query
Posted: Mon May 05, 2008 3:01 pm 
Getting Side Ways
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ok dunno how much help im gonna end up with but anyway..

if my 96 xh ive fitted 2 UHF's
both wired completely seperatly. one has a long range aerial. about 6" tall (not sure on the db rating or wateva its calle) the other is wired to a short fibreglass black aerail approxiomatly 2" tall. now the interference occure when transmitting on one the other squeels like a b**ch unless i close the squelch gate. for example. trasnmit on 40. the other reciever is on 28. the channel 28 squeels for a bit tthen sorta stops but still recongnises a signal on the lcd display however does not indicate the cahnnel as busy.

why does this happen?? dodgy wiring on my part?
or is it inevitable do i have to have my squelch gate nearly closed all the time thus limiting range????

any help appreciated.

one is a gme tx4000 the other is a uniden cant remember the model but is not just a base model unit is a fairly advanced unit however quit popular amounst the ute crew. cheers

xhute0 im lookin at you bud...

 

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Posted: Mon May 05, 2008 3:14 pm 
Getting Side Ways
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Make sure both unit's are using a seperate power source to each other and are grounded well.
Also make sure the aeriels are as far apart as possible, tuned and grounded properly.
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Posted: Mon May 05, 2008 4:32 pm 
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RedRoo wrote:
Make sure both unit's are using a seperate power source to each other and are grounded well.
Also make sure the aeriels are as far apart as possible, tuned and grounded properly.


Isolation is very important in RF systems with multiple transmitters. Can be a number of things. Antenna seperation, grounding and matching are a good place to start. Transmitter phase noise can get into the other reciever, kicking up the noise floor above the squelch open threshold. You could try isolated power supplys or put line filters on the supply line of each radio like RedRoo mentioned too.

Does your UHF use CTCSS? If so, it wont show busy as it's a false signal maybe (I.E. strong signal/noise present but no decode tone)

 

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