Cobra 29 SWR, cal meter

the same way you set it on any other radio.Look at the face of the set,you will see a switch that says S/RF,CAL , SWR. Now look at your meter and you will see a triangle that shows cal.Put your set on ch 1 with the switch in the cal position and bring the needle to that calibrate line on the meter by keying the mic. now release the key and set switch to SWR and key the mic again.Now write this reading down.Repeat for channels 40 and 19. If the reading is higher on 40 than on 1 you need to shorten the ANTENNA.If its higher on 1 than 40 you need to make your ANTENNA longer Always check 19 to make sure you have an average SWR. Any reading under 1.9:1 is good

put an external meter on it to get a match.

You are actually tuning the antenna to the vehicle it is mounted on here are some very good resources. http://www.rightchannelradios.com/pages/cb-antenna-tuning-guide-pv-c0-61.htmlhttp://www.wilsonantenna.com/swr.php

Be aware that if your radio has been modified it may produce a dirt signal that an swr meter may read as reflected power. In this case it may be more accurate set with a unmodified radio also if your radio is setup for a linear it may have a deadkey to low for the swr meter to calibrate correctly.
Hope this was of help.

S/RF/SWR/CAL SWITCH. When in the S/RF position, the meter swings
proportionally to the strength of the received signal. When transmitting,
the meter indicates relative RF output power.
When in the "CAL" position, the SWR meter can be calibrated by adjust-
ing the "SWR CAL" control to the "CAL" mark on the meter face.
When in the "SWR" position, the standing wave ratio is measured.

You will want to operate on S/RF position.

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

Calibrate For SWR (Standing Wave Ratio) http://www.cbtricks.com/radios/cobra/29ltd_bt/graphics/cobra_29ltd_bt_om.pdf
The CAL is only to calibrate meter for a swr check of you antenna system it does not calibrate radio.

first of all you are going about it wrong. To set your SWR you check it on channels 1 , 19 , and 40. If you reading is higher on 1 than on 40 you have to shorten your antenna . if its higher on 40 than on 1 then you have to lengthen it. before you do any adjustments to it ,loosen the set screws and let the antenna fall to the bottom then bring it up 1/4 " and tighten the screws. You should also use an external SWR meter not the one on the radio. Thats good for making checks every once and a while. With the meter you key the mic and have the needle go to set then put it on for and key the mic to obtain you reading . Anything under a two is good .

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..

If the radio is working don't worry about the meter unless you absolutely want it. These little meters are not very accurate or reliable. Get an external SWR meter to check the antenna.

You should not calibrate the antenna before you install it on the car!! the antenna needs to be calibrated on the vehicle that it is going to be on. Type of vehicle, different mounts, and many other variables can change the amount of reflection you will get.

j0hn9999 did a much better job but left some info out.

Take your SWR readings on channel 1, then on channel 40.... NOW, if your SWR is higher on ch 40 then ch 1, then your antenna is too long and it needs to be shortened. Refer to the antenna instructions on how to shorten the antenna.

If your SWR is higher on ch 1 then on ch 40 then your antenna is too short. You must lengthen the antenna. Again refer to your antenna instructions on how to lengthen your antenna.

You must calibrate each time you take a reading.

Make sure your doors and windows are shut when taking a reading

Make sure you are in an open lot when taking a reading as buildings, trees and other structures can cause reflection and give you an inaccurate reading.

If you adjust the length of your antenna on another vehicle and then put it on yours, the SWR will be off. It will need to be tuned again.

An external meter is better then the one in the radio, but will need to be hooked up in the vehicle you have the antenna on.

If you are not running any kind of power, or do not have a swing kit installed, and the radio is stock, the meter in the radio is more then enough to get a correct SWR reading.