I just bought a Uniden PC78LTW (stock) and a dual wilson fiberglass antenna kit, got everything hooked up and tried to tune it, the SWR meter was reading up to like 3.2 and its worse when the truck is running. I have no idea what to do.

 

A longer coax will help swr's also a good ground

 

the coax is 18ft long. Also i just remembered one of my buddies messed with the radio while i was wiring so when i hooked up the positive, the radio was on. Could it have fried?

 

You have to calibrate the meter on the radio before you start tuning and make sure the radio has a very good ground both at the radio and the antennas. I would look at hooking only one antenna up to get better performance out of it.

What type of antenna do you have? Is it a cut to tune or a top loaded antenna? If its a top loaded antenna all you have to is move the rod at the top of the antenna in or out to tune it. If its a cut to tune antenna you have to remove the cap and pull and cut off of the wire in the antenna to get it to the desired SWR. When you do this less is more.

 

Make sure the supplied cable is 75-ohm and not 50.

Insure both antennae and radio are well grounded as mentioned above. (That would be the first thing I'd verify, since things are worse when the engine is running.)

When tuning, be sure to adjust both antennae the same amount each time (and do not connect and tune each independently. They "play" off each other and change the overall SWR).

Duals on a "narrow-body" vehicle can be difficult to tune at all. Running a single whip may be better. Remember if you decide to do this, though, that you'll need to change to 50-ohm coax.

Where do you have the antennae mounted?

Andy

 

Also, no. Powering up with the switch on should have caused no harm.

Andy

 

One other thing to look at is your connections on your coax to your antenna and radio make sure they are tight.

 

you can always try it with the one antenna and if it works better then just the other antenna as a dummy.

like asked before whered you mount it. i know at first i had a bad mount and whip and bad location to mount it. moved up to a 4ft firestik and moved the mount and it works great now

 

if the ground was bad on the radio wouldn't it not turn on? the antennas are grounded to the mounts. would it matter if i unhooked one of the antennas to just run one or do i have to buy a single coax cable?

 

Where are they mounted? what brand are they. is the radio brand new?

 

I have had a radio that will turn on with a bad ground but I had what was called a ground loop that caused whining of the alternator through the radio and just moving the ground wire to its own dedicated spot solved the problem. I am guessing by your reponse that your kit came with dual coax the terminates into one connection at the radio so yes you would have to buy a singe coax.

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http://www.walcottcb.com/

 

1) the radio requires a very small amount of current to turn on, and could operate through a less-than-ideal ground. Different points on a vehicle have slightly (milliohms in most cases) differences in resistance to the "true" ground, the battery. The best solution would be for every wire in the vehicle to run back to a terminal strip at the battery, but this is obviously not feasible, so we do the next best thing: ground the battery to the vehicle frame, and everything else to that through various pieces of metal on the truck.

"The antennas are grounded to the mounts," but are the mounts well-grounded to the truck? Where are they mounted? Also what body-style is your truck? A whip mounted to the bed rail of a straight-side will be fine. The panel is made of metal. On a flare-side, they're fiberglass, so that won't work.

The best solution for a truck like ours is really a single antenna mounted in the center of the cab roof. A K40 or Wilson 1000 magnet mount would probably be my choice.

Andy