cb not recieving

[muddymech]

hi all

my cb does not receive very good, we checked with a hand held, transmitting is fine, receive is extremely poor at best. squelch has to be so high the back ground noise hurts to listen too.
had quick look at Ariel and its does not seem damaged.
does the Ariel and send and receive on the same parts. if its does then i can easily pull out cb and try it in another car.

[RangieBit]

Hi MM,

Most problems with transmit/receive tend to be feedline problems.

As per the heading, have you tested that the coax isn't shorted? Most modern radios will detune to protect the PA section of the radio if the SWR is high. They won't do it forever and they will still transmit a signal a short distance (such as to a handheld nearby).

Firstly disconnect the coax from the back of the radio, and if it's not permanently attached disconnect it from the antenna. Then using a multimeter (on continuity or low impedance setting - the one that buzzes when you short the leads together) check to see if there is an open circuit when you connect one probe to the centre conductor and the other to the shield on the coax cable/connector. If no buzzes, all good so far, if it buzzes, pull the coax and start again with a new run. Now if you were able to disconnect the antenna, reconnect it and try the test again. You should get the same result. If you now get a buzz, something is dodgy at the antenna end. Try swapping out the antenna for another. This is relatively easy to do if you have one of those that connects via an SO239 base.

If all of this tests fine so far, and as you indicate it's easy to move the radio to another vehicle, test that and see. If you get the same result as you started with, that is lousy reception, then this would tend to suggest a problem with the radio since that would be the only variable at that point.

Hope that helps a little. Let us know what you find.

Cheers,
Iain

[MLD]

if your aerial is a whip style you might have broken the wire wrap under the plastic coating. I experienced similar problems to you, a visual inspection of the aerial didn't show up the break in the aerial wire. I was able to twist the aerial base with the whip not moving. It was only a small amount of movement but enough to break the connection to the rest of the whip.

Otherwise Iain's solution is the thorough approach to the problem.

MLD

[muddymech]

thanks guys, will give it a go if my car re appears, at the moment its in the shop after a side swipe the other day.
ian

[Scouse]

That's a bit of bad luck - the accident damaging your UHF and all.......

[Xtreme]

Are radios (car based & handheld) both 40 or both 80 channel units?
On a recent trip, we had a mix of 40 & 80 channel radios and found that the volume received on the 40 channel ones was very faint. I'm not sure if the range of transmission was affected though.
Probably not applicable but just thought this may have led you to assume one was malfunctioning.