Cb radio I have great swr readings and people can hear me just fine sometimes. But when i key the mike my car radio fades out like the vol. is getting turned down and when i let off the sound comes back.

The antenna warning is the key, the swr on the antenna/feedline is very high. check antenna connections, coax and connectors for damage

For CB radio that operates in a relatively narrow bandwidth, you should be able to obtain "perfect" SWR readings for all 40 channels. That would be a reading of 1.1 : 1 or less.
The rule of thumb goes like this: if SWR is HIGHER on HIGHER FREQUENCY (Ch. 40 is higher than Ch. 1) then the antenna whip is too HIGH (too long/tall) therefore it must be shortenned. And vice versa.
Trimming the length requires patience especially when the reading has reached 1.5 : 1 or lower/better. Make a 5mm trim each time and then measure SWR then continue trimming until you are satisfied with the results.
The spike must be contributed by faulty electronic components inside the radio. The radio must be checked by a technician. But before you do that, trim your whip first and see what happens. Ideally, the length of the coax cable must be trimmed as well. But, since we don't live in an ideal world, we can ignore that for the time being. Goodluck. es

What was the radio that you keyed?

if you see the red light come on before you even set the swr you already have a problem.set the radio on cal and set the needle at the cal arrow.no unkey the mic . set the meter for swr and key it again.write this # down . go to ch 40 and do the same thing, then go to 19 and repeat. now that you have your readings you need to set the antenna. Now check it again for swr on 1-40-19keep doing this until you get an even reading on those channels.

follow these steps to adjust the
standing wave ratio(SWR).
1. Turn on the CB.
2. Set S/RF/SWR/CAL to CAL.
3. Key the Mic and rotate SWR CAL so the meter points
to CAL.
4. Unkey Mic.
5. Set S/RF/SWR/CAL to SWR.
6. Key Mic again and note the actual measurement on
the SWR scale. Refer to the following table to interpret
the reading.

1:1 - 1.5 Great
1.5 - 2:1 OK
2:1 - 3:1 Not So Good
Higher than 3.1:1 Terrible

Tune your antenna. If he took the metal whip out of the base, then he messed the tuning all up.




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.

To check the SWR, you put the swicth on CAL and key the mike with mike gain turned down all the way,then calabrate it to the meter on the CAL scale,then swicth it to SWR before you unkey the mike, then what ever the needle falls back to, that is your SWR reading.

After installing the antenna, follow these steps to adjust the
standing wave ratio(SWR).
1. Turn on the CB.
2. Set S/RF/SWR/CAL to CAL.
3. Key the Mic and rotate SWR CAL so the meter points
to CAL.
4. Unkey Mic.
5. Set S/RF/SWR/CAL to SWR.
6. Key Mic again and note the actual measurement on
the SWR scale. Refer to the following table to interpret
the reading.

1:1 - 1.5 Great
1.5 - 2:1 OK
2:1 - 3:1 Not So Good
Higher than 3.1:1 Terrible

The ideal standing wave ratio (SWR) is 1:1, or a meter
reading of 1 on the SWR meter's top scale. A SWR ratio
of 1.5:1 to 2:1 is excellent for most mobile CB antenna
applications.

Check the SWR on Channel 1 and Channel 40
If the SWR is higher on 1, make the antenna longer
If the SWR is higher on 40, make the antenna shorter
Most antenna's are adjustable. Make small adjustments at a time.

your swr setting are off wack fix your swr

1) push the button marked S/RF / SWR / CAL to CAL

2) Hold in the button on the mic

3) Turn the SWR CAL knob until the needle is over set to the far right of the meter

4) flick the switch (in step 1) to SWR

Your SWR reading will be displayed. The more to the left the better..