I just put an RFX75 in a cobra 29. I had some slight problems at first, but was able to work them out.
First I would like to through out an FYI. On the RFX75 page on cbtricks, there are 2 very handy documents that can help with them not working when new. There is a pre-installation guide, which has things to look for that will cause it not to work, that you can fix before install, and a troubleshooting guide.
I had a RF feedback problem. If I turned the gain up past half, I had issues. If any one has this problem, this is what solved it for me. I made sure to make all wires as short as possible. I grounded the audio transformer to the chassis. I also went around the radio and made sure all the ground points where good.
Grounding the audio transformer pretty much took care of it. Might have been an issue with this particular cobra 29. Haven't seen anything else around on the net about this issue.
Also, with tweaking I was able to get just over 150 watts pep out of mine dead keying about 23-24 watts. Its doing just over 60 watts AVG. used a 1 k tone for testing. AMC is not wide open either. I did tweak it using my mod meter but found turning it way down still produced full swing on the meter.
I found that with out dropping the dead key produced some back swing. Did a bit of testing in the field. Had a buddy of mine key it up, with out any swing mod. It was dead keying 40 or so watts. Once I got far enough away to observe the swing, it was swinging back quite a bit.
I found that good forward swing was achieved at around 23-25 watts. Could probably go a bit more on the carrier, but that's where I got the best forward swing without sacrificing audio. If I brought it any lower then 20 watts the audio started to suffer and got raspy. more swing, but raspy.
At about 3/4 on the mic gain produced devilishly loud audio. Right on the cusp of too much. With a modded RK56 its sick.
after the slight difficulties, its one mean barefoot duck stomping machine.
