Crazy UHF problems.

I have a Uniden UH7700NB 80 channel that's been in storage for 8 years or so. Stored well, in great condition. I recently fitted it the patrol with a new fairly cheapo maxtrac aerial. Can hear chatter but can't talk out. Tried two other UHFs and they behaved exactly the same. Today I returned the cheapo aerial and got a nice 6db GME. Fitted all up and still have the same problem: can hear workers chatting away but can't broadcast to my handheld.
Weird bits:
If I talk on the handheld and scan with car then the car stops one channel past the hand-held and picks up violent screeching that has a hint of my voice.
If I hit the talk button on the handheld, the "signal received" symbol appears on the car but that will happen no matter which channels either are on.

I have gone through the manual and am pretty happy that all settings are where they should be.

Any tips?

.......from under the great down under.

I did a factory reset and now it seems to send and receive to the hand held but only if it's one channel apart. Ie handheld on 24 and car on 25 works but not if both on 24 or both on 25? What the heck is going on there!?

.......from under the great down under.

Sounds as if it is sort of acting as duplex on simplex mode. Maybe?

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Originally Posted by mudnut

Sounds as if it is sort of acting as duplex on simplex mode. Maybe?

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It mentions duplex in the manual but I don't fully understand it. It's for use with repeater stations right? So the UHF will display channel 1 but it transmits on channel 31 to the repeater which repeats it as channel 1? Something like that?

The car UHF and handheld will only communicate if the car is one channel up from the handheld. Weird. Also, I could hear some workers chatting, coming out of both uhfs at the same time and one was 20 and the other 21.

.......from under the great down under.

Quote:

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Originally Posted by taslucas

It mentions duplex in the manual but I don't fully understand it. It's for use with repeater stations right? So the UHF will display channel 1 but it transmits on channel 31 to the repeater which repeats it as channel 1? Something like that?

The car UHF and handheld will only communicate if the car is one channel up from the handheld. Weird. Also, I could hear some workers chatting, coming out of both uhfs at the same time and one was 20 and the other 21.

.......from under the great down under.

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Bear with me, as yours is a different model. I've just got your models online manual.

Yours has basically the same operating system as mine, but I can't find my paper manual. I seem to remember seeing advanced settings to change channel parameters on duplex. Try another factory reset. Being in storage so long, my have let some data be corrupted. @TPC your turn mate.

Are the numbers on the display operating properly?

Duplex should only be on channels 1 to 8 so that shouldn't have anything to do with it. Sounds like one of them has gone a long way off frequency. I can check them, you just have to come up to here, make sure you bring a flynet.
Attachment 87385

Quote:

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Originally Posted by TPC

Duplex should only be on channels 1 to 8 so that shouldn't have anything to do with it. Sounds like one of them has gone a long way off frequency. I can check them, you just have to come up to here, make sure you bring a flynet.
Attachment 87385

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I'd love a trip but it might be a bit more cost effective to get one of those icom ic-455 you've mentioned.....

.......from under the great down under.

Just make sure all of your power connections and earth connections are clean and secure. Even undo the fuse in the fuse holder and give everything a good clean. If there is a bad connection and the voltage to the set is too low they can do odd things, especially when you transmit as it then draws more current and the voltage drops even further.

Worth a try.

Cheers mate. Yep, checked and rechecked everything. Has a new power supply straight from the aux battery. Fuse checked and cleaned.

.......from under the great down under.

Quote:

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Originally Posted by taslucas

I have a Uniden .

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Based on my experience with one that could be the problem. Tried everything. When I switched for an Icom, & with same antenna & wiring. I concluded the problem was probably an internal earthing problem or something like that from new. ie a quality control problem.

Although I get the impression that yours used to work ok?

I took the UHF to a specialist and the short answer was "it's cooked mate". The output is blown. Being a cheaper and discontinued model it's not worth fixing. I purchased a refurbished and tuned Oricom uhf030 from him for less than half the current retail price. Happy days!

.......from under the great down under.

Not about the channel offset, but regarding the cheapo aerial vs. the nice GME one: have you done VSWR tests to shorten your aerial to the exact fraction of the wavelenth?

Cheapo aerial didn't work with two other UHF units so I reckon it was cooked. New gme aerial and refurbished UHF works a treat now. Happy days

.......from under the great down under.