Benelec BL2000 (UHF) probs

[bakerboy]

Gday guys, just a quick question, just recently (last month or so) my benelec has been knocking my cd player into protect mode if i transmit for 10 or so seconds (or longer). It never did this when i first installed the unit and could chat till the cows came home. What should i be looking at to correct this? The unit is still under warrenty, and the company i bought it off is very helpful and im in no doubt that they will help me out, id just thought id try to sort out any obvious problems first

The unit is mounted below my cd player like the picture below (just imagine the benelec in the place of the uniden) The power and antenna for the uhf runs through the firewall at the passengers feet, with power for the cd player coming from the original wiring harness. It will only knock the cd player into protect mode when its on cd, radio tuner or aux, standby mode is fine

[robbage]

I'd be looking at the antenna system first. All your RF should be getting to the antenna but it sounds like it might be radiating from the coax. Check that the connector hasn't failed (ie check for a short across the shell to the centre pin & check for continuity from centre to antenna tip) An SWR meter would be useful. Also check the connection at the antenna base. Check the full length of the coax for cuts or crushed spots. Make sure the radio is properly grounded.

[bakerboy]

thanks, i will check the connection at the back of the radio first as it is a tight fit behind the console

[vk6hgr]

Robbage's idea is a good one. I'd also have a look at the DC power cable going into the transmitting radio - is it close to the power lead of the CD player? Is the negative connection solid? (If it's loose the radio could be connecting to the battery negative through the antenna lead - there could be some stray RF going into the CD player that way.)

[bakerboy]

havent had a chance to play with the antenna, however looking through the manual for the cd player, protect mode occurs when a speaker wire has a short or touches the chassis of the vehicle, im unsure how that could happen when talking on the 2way and only for periods of 6secs or more

[robbage]

It's probably a false symptom. The RF is probably driving it whacko. Stray RF can also set off air bags and mess with your car computer.

[bakerboy]

well im safe on the airbag side of things

another thing before i suss this out, i will be getting a pair of spotties, and fitting hid kits into them. The antenna is only about a foot away from the ballast, will this have any effect on the UHF, and if so, is there anyway to avoid this? mounting the antenna on the roof isnt an option, i only just fit under carparks as it is

[robbage]

HID lamps generate quite a bit of RF noise. They are a gas discharge lamp.. basically an electric arc. The first radio transmitters worked much like that
I know people have had problems on 27 MHz CB and broadcast FM. Dunno about UHF CB though.