AM CB radio constantly receiving when ignition o

[ADog]

Hi,
Ive tried to research my issue, which is whenever I turn my vehicle ignition on the radio comes up "busy" as though it is receiving a constant signal. When I disconnect the antenna it drops away which leads me to believe there isn't an issue with regard to the power wiring?
I have earthed the antenna straight to the battery negative but no difference. My next step is to earth the housing of the radio directly to another earth point. But apart from that I am a bit lost on what to do next. If anyone has any suggestions?

[Bombero]

Hey Adog..

Try grounding to radio to the vehicle instead of the battery and make sure you don’t ’key up’
the radio while the antenna is disconnected.

Bombero

[MDYoungblood]

Hello ADog, welcome to the forum. I need a little more info, type of vehicle, type of antenna and brand, how the antenna is mounted, and last what brand radio.
I would also do what Bombero said, the antenna’s ground should go to the body of the vehicle.

3’s

Greg

[ADog]

Hi, thanks for the replies.

The radio is a GME GX400B 26mhz AM radio. The aerial I'm not sure about and the vehicle is a Nissan Patrol.
I checked continuity between the coaxial cable where it plugs into the radio and the aerial base, there was nothing, so I assume somewhere along the coaxial cable there is a break in the shielding. I assume this to be the reason for my troubles? Earth is good on everything else but I have nothing from one end of the cable to the other, I do have continuity on the centre copper though.

[MDYoungblood]

G’day ADog, I should have looked at where you are at. Nice radio, I am going to guess the antenna is a magnet mount. The noise I am also guessing at is the fuel pump, it is probably picking up the from the fuse box where the radio’s power source is connected. You most likely hear the noise with the key on but the motor not running. My suggestion is to connect the power source directly to the battery, only need to do this with the positive lead and the negative to a good grounding location under the dash. This might help. The other thing is your antenna needs to be adjusted to the lowest SWR (standing wave ratio) so it picks up more signal on the CB band and less static or manmade noises.

3’s

Greg