More Cascadia woes

Hey all...I have an issue that seems to have stumped me and even a couple of cb shops. Maybe some of you can help me, but if not, at least it'll be a good read...

A little background: I bought a Stryker 497hpc from Styker cb shop in OKC (ok...a mistake) in which I traded a very nice Mirage mx36hp plus cash for. I take it, put it in my '13 Cascadia, and off I go.

The radio worked flawlessly for 2 weeks.

I took my truck to our yard to get the apu worked on, and when I got the truck back and turned the cb on, it was acting really wierd. What it was doing:

A) it had no receive. It was phasing in and out of frequency.
B) anytime I keyed up, I got a godawful humming feedback noise coming through the radio and it was exasperated if I had the am/fm radio on.

Thinking that it was possibly the stock coax being fried, I went to a cb shop and gave them $150 to run coax and set it all up correctly. They ran the coax through the stock mount, and used a 4' skip shooter antenna. My swr's are at a 1.3 across the board. But the radio is still acting up...no difference. I tried keying up and got rf burn on my hand from the spring on the Astatic mic...great.

I take the radio to another cb shop, and they open the radio up. They tell me that whoever did the conversion did a shoddy job, and they fix it. He tests the cb out through a dummy load and over their antenna and it sounds/works great. I hook it back up to the truck and now it will receive, but still all the symptoms when I transmit....except the rf burn because I'm avoiding touching that spring now. I also swapped out to my backup Astatic mic which helped some.

The only way that I can transmit as of now is to have the power all the way down (2w dead key...6w swing) and it still has a high pitch whine and a rhythmic popping noise in the background. If I turn the power halfway up, I can no longer be heard over the hum/rhythmic popping sound.

Here are a couple of things I don't get... 1: I know I need to run the cb directly to the battery ( and that's my next thing to do.) The cb shop that I went to firmly believed that was my problem. However, the cb worked just fine using the supplied posts up until the shop had my truck...so why wouldn't they be sufficient now? 2: Even at very low power (less than a stock Cobra 29,) I'm still having transmit issues. That would make me think a radio issue...yet when he had it hooked up in the shop it worked great.

I would conclude that, whenever they were working on the apu, they did something to cause the issues that I'm seeing. The apu wasn't charging the batteries, and I saw one of the mechanics messing with the battery cables some. I'm an amature though, and don't know much of anything about this stuff. This radio is only 3 weeks old, and I've already spent over $600 total trying to get this right. I'm running out of money and am at a loss.

Any ideas??

Edit for video

 

We did that with a Cobra 29...no issues.

 

Updated for video

 

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[FONT=Verdana, Arial, Tahoma, Calibri, Geneva, sans-serif]Thanks for the idea, but I have tried to call Stryker for 2 weeks now. It always goes to an answering machine after 4 rings. I've left a couple of messages, but nobody has returned my call.[/FONT]

[FONT=Verdana, Arial, Tahoma, Calibri, Geneva, sans-serif]On another note, I stopped to get fuel earlier, and the radio worked perfec[/FONT][FONT=Verdana, Arial, Tahoma, Calibri, Geneva, sans-serif]tly...for about 10 minutes. It went to hell shortly after I started driving again.
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Nobody else has any ideas or suggestions (besides junking the $400 radio for a Cobra 29?) Certainly some of you radio experts has an idea.