CB Radio Repair
Technical Questions for March, 2009
Q: What is the difference between SSB and extra channels and uppers and lowers?
A: Uppers and lowers mean the same thing as extra channels they are interchangeable. On most 10 meter radios they will have more than 40 channels grouped by band letters A thru F for example. Were as each letter will represent a grouping of 40 channels.
SSB (single side band) is a different mode of transmitting and receiving in addition to AM and FM.
Q: My radio cuts in and out sometimes? When I have the radio checked it test fine. I have my antenna system checked and the SWR’s are 1.5. What do I check next?
A: This is a tough question to answer, but if the radio test fine on test equipment and the antenna system checks out at 1.5 or less, then I would suggest to test the radio / antenna over a coarse of several days by watching what may be going on for example. Does the problem only show when you are moving, if so maybe the antennas are cracked, which may show good SWR’s when standing still. If you are having the problem when the antenna system is wet, I would look for loose connections or corrosion around the bracket and stud of each antenna. Flex the coax at different places if it seems stiff and or brittle replace it.
By doing a little investigative work you may solve your own problem.
Q: Why do I need a mic plugged in my Cobra 29 series radio to hear on receive?
A: Several of the CB manufacturers designed their radios to pass the receive audio thru a couple of connections in the mic so with the mic plugged in you complete the circuit and allow the receive audio to pass thru.
With out the mic plugged in you can still see the meter bouncing as you receive a signal but you do not hear anyone because the circuit is not completed to the speaker system. Then after plugging the mic in you start to hear the receive audio.