CB only transmiting ten meters
 

I bought a second hand GME TX4400 FM CB radio that was previously fitted to a TJ including loom, fuse and antenna.

http://thumbs1.picclick.com/d/l400/p...Radio-80CH.jpg

I fitted up to my TJ it receives ok but only transmits for a distance of ten meters, if you go any further away you cannot receive it's signal at all.

any ideas?

I'm from the 27 MHz and swr meter days so I know little about troubleshooting FM CB's

If you're receiving Ok but not getting any decent range on transmit, then the output stage of the radio is probably faulty.

A quick check with a UHF SWR/Power meter should be able to tell you if the antenna tuning is Ok and the power output of the radio.

An antenna fault is a common cause of a blown output stage, or leaving the mic keyed down for too long.

Cheers

CB transmits 10m
 

If its transmitting anything at all over 10m I'd say its not the output stage of the radio circuitry. You would get nothing at all if the output stage amplifier was blown or shorted. Its only 5 watts, not 25w or 100w. There's not a lot of power there.

I would sugest you have an antenna cabling issue. Disconnect the cable off the back of the radio, test the impedence (resistance) between the centre conductor and the outside of the connector. Its been a long time and I can't remember if it should read 50 OHM or open circuit, but it should definately NOT be a short.

Then, check the impedence from the antenna base centre conductor to the centre conductor of the plug. This SHOULD be a short or very close to 0 OHMs. Same with the outside of the connector to earth or the outside of the antenna base if using a PL or SO type base.

This is one reason I only used raised feed ground independant UHF antennas with pre installed cables. I only have to worry about terminating one end correctly for itvall to work regardles of where I mount it, to some extent. Mounting UHF radios on motorcycles taught me a lot of tricks.

thanks for all that info and good advice


As it turned out it was the unit that was faulty, I bought another cheap one on Gumtree that works well - gotta love Gumtree, sometimes you win.... :D