How to replace rf meter on cobra 29 - Cobra 29 LTD CB Radio

SOURCE: how do you replace the meter light in a cobra 25?

You need to open the unit up ( remove the case/cover). Then remove the 4 screws holding the face plate on. Remove all the knobs ( they slip off) . remove any screws holding the meter on ( there may be none depending on which model you have ) . slide the meter out of the face plate and replace the meter with a new meter. Note: The meter light needs to be reistalled in the new meter. It simply slides out the side of the old meter and slide back in the new meter. Replace all the screws, and the jobs completed.

Good Luck and a good weekend to you.
Ed
NC Electronic
Mills, Wyoming

Mechanic688

• 204 Answers
• Posted on Nov 05, 2008

SOURCE: cobra 29 LTD classic LCD channel display replace

Hello, the channel display is kind of touchy, as far as getting to it and of course it is soldered to a small circuit board and there is a certain way it goes back in. There is about 9 legs on top and 9 on the bottom that need to be unsoldered and resoldered( carefully). You can buy them in red,green, and bue. The meter light is pretty straight forward. You have a hot and ground wire. I used to use colored LED lights in the meters, way cool. They are not hot, and they last almost forever. The LED's are fairly easy because if you hook it up backwards, it just won't do anything. Let me know if you feel comfortable doing the solder work, and take a look inside the bottom cover at the channel selector because it has to come out with the channel readout. I used to charge $25.00 just for that because it would take me an hour just for the ch. selector, and about 15 min. for the meter light. Let me know one way or the other,,, Mechanic

SOURCE: cobra 29 ltd modulation problen

You need to check the modulation on a modulation meter. Just because the meter doesn't peg, doesn't mean the modulation isn't working. Usally a meter pegging, means the swr's are too high or the meter is misadjusted. If in fact the modulation is low, their is a pot inside the radio (VR4) that will add gain to the modulation circuit. This setting is legally supose to be set by a qualified technician.
Good Luck
Ed Meshechek ( Radio Man )
NC Electronics
PO Box 1696
414 6th St.
Mills, Wyoming
82644
307-266-4675
[email protected]

SOURCE: cobra 29 nw ltd won't transmit

Have you cracked the radio open yet?  check for loose connections etc.  get back to me if that doesnt yeild any results

SOURCE: cobra 29 ltd classic antenna calibration ??

Wow. That's not at all a solution to what this guy is asking. And why all the caps??

The one point jm77437 has that is correct is that you do not set the radio, you set the antenna. The rest is blah blah.

Here is how you tune your antenna for you radio. First off it depends on what kind of antenna you have. most fiberglass antennas have a tunable tip to adjust the height of the antenna. Metal whips either have a collar at the base that the whip will either slide up or down in to adjust the height. The other type of metal whip's you have to physically clip to shorten the antenna, you must be careful with this type because once its clipped, that's it. You cannot add what you cut off.

I am going to give this example using a metal whip with an adjustable collar.

First after your radio is hooked up in the vehicle, drive to an open lot. Buildings and other structures can cause extra reflection. turn to channel 1. Flip the meter to CAL. Key the mic without talking. Now turn the CAL knob up until the needle reaches the little upside down triangle all the way to the right marked CAL. Now you have just celebrated your radio for your setup to measure you SWR. Now while still holding the key, flip the meter switch to SWR. The needle will move, and where it stops is your SWR reading. The lower the better. Anything under 1.5 is considered really good. But still, the lower the better.

Make note of what your SWR was on ch 1.

Now flip to channel 40. Repeat the SWR process. You must recalabrate each time you take a reading.

Now like jm77437 said. If your SWR reading is higher on 40 then 1, then your antenna is too long, and you must make it shorter. Loosen the collar and lower the antenna in the collar 1/4 inch at a time. check the swr each time you adjust the antenna.

If your SWR reading is higher on channel 1, then your antenna is too short. You must make your antenna longer. Do this by loossening the collar and pulling the antenna upward in the collar 1/4 inch at a time, again checking the swr each time you adjust the antenna.

What you want to achieve is having the same SWR reading on channel 1 and 40. then you have the best match you are going to get with that antenna.

If your swr is under 1.5 on all channels, you don't need to fuss unless you are a perfectionist. then by all means go ahead.

If your reading is higher then 3, or your ant light comes on, something is really wrong. Make sure your antenna is connected all the way, and the coax is not damaged.

Its important to have an appropriate SWR because if you do not, you are reflecting too much signal back into the radio, and eventually you will burn out your final transistor, and your radio will be toast.

Some tips: make sure you check the swr with the doors and windows shut. Make sure you are in an open lot. Remember to calabrate ecah time you take a reading. If you have had your radio peaked by a radio shop, and they have lowered your dead key, or have done a swing modification, then the meter in your radio will not work when taking an SWR reading and you will have to use an external meter.