Uniden pc 78 elite cb

The coax jumpers between the meter and the radio can change the SWR a little bit. It is very unlikely the the antenna can be that low on 1 and 40. Set it for the lowest on 20 via the radio and as long as you are under a 2 on 1 and 40 then it should be OK.

If you cannot use a magnet mount antenna on the roof then a fiberglass antenna (top loaded) about 4 ft. tall mounted behind the cab on the bed rail.You can usually run the coax thru a rain drain hole in one corner of the bed. The antenna should be tall enough to where the top third of the antenna is above the roof. The taller the ant.is the better the SWR will tune.

above the rear window should be a tubular hold down handletry mounting it there.does this truck have a fiberglass body as others do? If it does try grounding the antenna to the chassis with some heavy duty wire maybe like 12 or 14 guage. I drive a ch650 and to switch trucks I have to check my SWR constantly and ground the antenna. you could turn the volume up a little too. SQuelch all the to the left and RF gain all the way to the right.

then the antenna needs to be moved. antennas have to have a ground plane to get correct swr below 3... or there may be a bad ground. try moving antenna @ different angles to see if it changes swr's or even opening the door away or closer to the body will make it change. also check the insulator it should be on top. call if you need help

The antenna needs to be tuned. The reason all of a sudden your SWR is a 4 when it used to be a 2 is, after a peak and tune, the radio is putting out more power, there for more RF energy is being reflected back into the radio. That is why the antenna has to be tuned.

It is important to tune your CB radio antenna to the proper length. The length must exactly match the wavelength of the frequency you transmit on. Or be really really close.

All Cb antenna's have a way to adjust the length of the antenna. If it's a mag mount, the metal whip can be slid in and out of a metal collar. Usually a set screw. If its a fiberglass whip, the way to tune it is on top. It either has a small metal rod with a set screw to adjust the length, or it threads in and out to adjust length.

Either type you have it will need to be adjusted for proper length. Here is how to tune the antenna to lowest SWR.

Some radios have a built in SWR meter. Some do not. If yours doesn't have an SWR meter, then you have to use an external SWR meter. Radio shack carries one, and you can find them cheap on ebay.

If you have a built in SWR meter or external, the procedure is the same:

1. Turn the radio to CH 20.(This is the center of the band.)
2. Switch the meter switch to CAL. (CAL stand for calibrate.
3. Key the radio. (Important. Do not talk while keying the radio.)
4. turn the CAL knob up until the meter hits the CAL mark.
5. Now while still keying the radio flip the meter switch to SWR.

Where the meter falls after that point is you SWR reading. If its above 3, that is real bad. 2 is not gonna kill your radio but its not the greatest. 1.5 and under is a good place to be, but the lower the better.

If your SWR is high, Here is how to find out if your antenna is too long or too short.

1. Turn to CH 1
2. Repeat SWR procedure. You must calibrate every time you do it.
3. Remember the SWR reading.
4. Turn to CH 40.
5. Again repeat SWR procedure.
6. Compare the reading between CH 1 and CH 40.

Now if the SWR is higher on channel 1 then channel 40 your antenna is too short. You must make it longer.

If the SWR is longer on channel 40 then on channel 1, then the antenna is too long, you need to make it shorter.

Make height adjustments about an eight inch at a time, and take reading each time.

once the SWR is significantly lower and the reading on channel 1 and 40 are about the same, you a about matched. At this point turn the radio to the center of the band, channel 20 and take an SWR reading.

You should now have a low SWR reading, 1.5 or under. If you are 1.5 or under, you are good to go.

If you cannot get the SWR to an appropriate level, there may be an antenna problem.

You say your SWR is good. Have you had it checked? Just because everything is new or good doesn't make it a match to your truck.

A ground wire will not replace the lack of ground plane. Try a different antenna altogether (possibly one with a magnet mount) and mount it on some metal surface like even the front hood and retest.

I am sure the problem you will find is with the lack of a proper ground plane.

I hope this will help you on setting your swr put the radio on channel 1 check your swr.
now go to channel 40 check the swr. If the swr is lower on 1 than it is on 40 the antenna must be shortened buy 1/4 inch.until you reach your desired swr.if the swr is lower on 40 than it is on 1 the antenna must be lenthened by 1/4 inch until desired swr.

You Need to check and set you SWR on the antenna system. You may also have a bad coax or the ant studs ( mounting hardward ) for the antennas may be bad. It definally sounds like an ant/coax problem Good Luck
Ed
NC Electronic
Mills, Wyoming

If the antenna is tunable, you definitely need to start out by having the swr set properly on the antenna. Also, make sure the plastic ferrel, (the small round white piece) is between the top of the antenna bracked and the antenna itself. It is there to make sure the antenna does not ground out to the vehicle. If the antenna is grounding out, it will be like no antenna at all. I have also had a few customers that have had broken coaxes straight out of the factory package on cheaper antenna setups.

Dean
Rollin CBs