This is illegal.How do peak and tune my cobra 21ltd cb radio?
Do not mess with the circuit! Unless you have a electrical engineering degree... dont! The best way to improve performance is by improving the antenna and using a SWR.
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How do peak and tune my cobra 21ltd cb radio?Unless you know how a transceiver circuit works then you will totally screw it up by adjusting the coils in the circuits. In order to peak a CB (newer CB's can not be peaked as they have permanently fixed tuning coils) you will need a tone generator, an oscilloscope, a 50 ohm dummy load antenna, and the schematics diagram for the radio. Locate the zenier diode that limits the voltage to the final output driver transistor and cut it on either end. Using the tone generator, inject a 1khz tone into the microphone and wrap a rubber band around the mic button to hold it down while you are tuning the TX coils. Connect your oscilloscope to the antenna and adjust the voltage level on the scope so that you can view the sine wave from the tone generator as it is output through the transmitter. Making only small adjustments at a time, tweak the TX coils until the sine wave is at the highest voltage level you can get without clipping the signal. You now have a peaked CB transmitter. If you don't understand any of this then you will have a screwed up CB that will be extremely difficult if not impossible for even a professional technician to get back in tune. I would suggest taking it to a CB technician to have it done. There's usually one near any truck stop inside a big city.
if your asking you probably dont know what to do inside... you need to bring it to your local "cb tech" and hope he will do it, and do it right. it shouldent be expensive. probably less than 40 bucks
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