Hi,

I mounted my Cobra 75 like many people seem to do, under the glove box, zip-tired to the metallic bracing. I have an issue, though, whenever TXing, even if I press the talk button for a second, the right speaker(s) will both squak loudly. I do have the infinity system, and I think it may be due to the amplifier being near the little power box.

I'm going to try moving the power box out from within this area, and also try a friend's power box, to see if it's just mine - but I was curious if anybody else had run into this, and if so - how they'd corrected the issue. It only occurs when the car itself is powered on/amplifier is energized. I wired the CB direct to the positive and negative terminals of the battery, through the foam hole that you can access via popping off the side panel. The coax is run along the floorboard/under the kick panels. I really hope it's something people have solved, as I've already cut my dash for the quick disconnect of the CB itself.

Thanks!

 

Additional info:

I'm using the teraflex tailgate bracket, I did sand it and use the bolts included. I'm also positive I installed the fire-ring cable properly (I have a 4' firestik), with the plastic spacer in the right location, I used a diagram from their website. I may try getting a wire run from the part of the fire ring thing that's supposed to be ground, and running it to something bolted to the tub (any suggestions?) to see if it's a grounding issue with the antenna.

I didn't get the antenna tuned yet, because I couldn't hold the TX button on the cb without worrying about slaying my speaker. I may go try to tune with the vehicle off, just to see if something is really far off in that regard. Should show up as terrible SWR if that's the case, I would assume. I'll report back if that yields anything. I'd REALLY love feedback from anybody else who might have ideas, as I know very little about any of this, and searches haven't been too helpful yet.

 

Ok,

It's definitely not a grounding issue w/ the firering/mount, I used a multi-meter and was able to verify that one lead on the battery ground, one lead on the antenna cable outer ring, very little resistance. In fact, I went ahead and hooked up an SWR meter, and even being in an underground parking garage, I was able to get SWR nice and low on channel 1/19/40. With the radio off, no noise at all from any speakers.

With the radio on, however, I still get a lot of squeaking/squawking from the right tweeter/speaker. I'm wondering now if it's my radio, somehow feeding the amp some kind of RF it's picking up from TX?

 

Reground the radio chassis to a metal part of the jeeps frame, see if that helps.
Run your coax as far away from any other audio harnesses as possible too.

 

The radio is two parts, the hand-unit which is the actual radio bit/display/etc, and the little power/antenna box. The power/antenna box is wired (positive and ground) directly to the battery. The coax is run along the passenger side floorboard, the audio harnesses/HU are all mid-dash, and the amp is the factory infinity amp under the driver's side of the dash. I can't really run the coax any further away aside from outside of the chassis.

I really hope doing something like placing a ferrite bead right prior to the amplifier may help, because this is very frustrating. Thank you for your advice, if you have any other ideas, let me know!