The Cobra 29, like most CB radios, contains a reverse-polarity diode whose purpose it is to protect the radio against accidental reverse-polarity hookups. Normally all you will need to do is replace the fuse, then hook the radio up correctly.
If that doesn't get you going, then possibly the polarity-protection diode is now shorted and will have to be replaced (or removed - not recommended).
Beyond that, my experience is that the next component most like to get damaged is the Audio Output circuit, either an IC or a power transistor (larger than a regular transistor). At this point you're going to have to take it to a repair shop.
SOURCE: cobra 29 ltd classic antenna calibration ??
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.
123 views
Usually answered in minutes!
×