05 Volvo 780I tractor trailer install problem/quirk

[rbodenbender]

the facts...........05 Volvo 780I tractor, Galaxy Pluto w/ the astatic 636L and astatic echo board, mini monkeymade antenna rated for well over 10k watts, running the mini "grey" coax with a dead key SWR rating of 1.3 to 1 on channel 19. the antenna bracket is stainless steel and is connected to the factory ground strap that the Volvo trucks have for antennas.

i recently bought a texas star 250 mobile amp, and driving it with 3.5 watts swinging 30 watts is giving me an average PEP of 350 watts or so. the problem that has surfaced is when the amp is turned on, the radio feeds back really bad. i have to turn the mic gain almost to 10 o'clock so it wont squeal. the linear is fed by a main power circuit inside the cab that is direct to the batteries. it blew a 20 amp fuse so i gave it a 25 and its fine for now.

the radio has a chrome case and is fed to the factory Volvo CB studs. the linear is taped on top of the radio with double sided tape. the linear is grounded to the frame of dash inside of the truck. i also have a ground wire from the side of the linear case to the CB mounting bracket, and a wire from the mounting bracket to the negative power stud. when i can get it to operate fine, i feel current in the mic wire, meaning it is grounding out through my hand. the astatic is one that has the tangle free cord that is made of metal, and it has burned the snot out of me on the leg once and on my hand.

anyone have any ideas? when it is talking, its walking the dog. none of this started till the amp was installed so it tells me it has to be a grounding issue but i was wanting some suggestions from a few of the people on here as i am sure this has happened before. i would like to think this mess is grounded enough but who knows these days. they are making these big trucks out of fiberglass and plastic these days.

any input or questions are welcomed. thanks in advance.

Rob

[51]

!. 30 watts pep is way to much drive for that T.S 250! at that level it wont last long at all, no more than about 15 watts pep for that amp to be happy.
2. current draw on that amp is 26 amps average peak so that's why you're fuse was popping.
3. you have rf hot spots in your station due to a possibility a few things like: insufficient ground, ground loops, and inadequate wire size among other possibility's.
I bet these are you're primary issues that you should look into to start.