Cobra 19 ultra 3 cb board layout - Cobra 19 Ultra III Citizen Band Radio

SOURCE: how do i turn peak and tune my cobra 19 ultra 3

un-solder 1 leg of D11 diode, pull it out of the board, and make sure it does not short against anything.

That will bring your modulation up all the way. there are other adjustments that can be done, but without proper meters, you will most likely mess up the radio.

D11 will be a big step up any way.

SOURCE: installed a cobra CB ultra III on a motorcycle

The external speaker jack was not designed for a head set. It has too much power it over loads head set. You need to solder a resistor in line with the negative wire. You will have to experiment to see which value gets the audio just right for the head set you are using.

SOURCE: how to modify a cobra 19 ultra iii cb

find DM1 and clip it. then you will have full modulation.

SOURCE: i have weak talk back signal

Did you tune the antenna??

The antenna needs to be tuned for best SWR.

If the antenna is not the right length, then you will get signal reflecting back into the radio. this is bad and it can damage a radio.

The 29 has a built in SWR meter.

The lower the SWR the better.

Here is how to check the swr.

Turn to ch 20. Put the sf swr cap switch to CAL. Key the radio. With the radio keyed, turn the cal knob up until the meter is all the way to the right on the cal mark. with the radio still keyed, flip the switch to SWR. Where ever the needle falls is your swr reading. The top line is SWR. If it is above 3 this is really bad, and your antenna is no tuned and you are hurting your radio. You need to adjust the antenna length.

Turn to ch 1 and take an SWR reading the way I explained. Then do the same on ch 40. IF the SWR is lower on ch 1 then 40, your antenna is too short, make it longer. The antenna has a way of adjusting it. Usually the whip slides up or down in a colar.

If the swr is higher on ch 40 then 1, it is too long, and you need to make it shorter.

Keep making adjustments until the reading on 1 and 40 get lower, and are about the same.

Then check ch 20 again. It should be low, 1.5 or under. Then you are good to go.

you will find people hear you a lot better, way better then ever.

SOURCE: WHEN I TAKL HAVE DISTORTION

your not out of frequency. Your antenna is not 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.