Question about Cobra 29 LTD CB Radio
I want to get more power out of my cobra 29
All he is asking for is this...
Find VR4. Its near the big transformer. Turn it all the way to the left. That is your AMC. that will turn your modulation all the way up.
If you have a power meter you can raise your dead key, or carrier signal as raising the modulation only effects your swing.
If you don't have power meter, then don't mess with it. Increasing the modulation will be a big improvement.
If you do have a power meter then here is what you do. Find L12 near the final, is near the heat sink in the little space near the transistor. that is your final. Turn this out, to the left, with the radio keyed until the needle stops moving up. don't turn it out any more.
***** NOTE IMPORTANT *******
Do not do this with no antenna hooked up, or without a dummy load. You will blow up your final. You can never key the radio with out a 50 ohm load on the radio.
You can make a simple dummy load to do this inside instead of out in your vehicle. Take a CB coax and 5 150 ohm resistors. Hook the 3 ends of the resistors together and solder them, and do the same with the other side. then solder on end to the center piece of a coax, and then to the out side piece. that will give you a 50 ohm load when you connect it to the radio. If the Ant light goes on, stop right away you did something wrong.
You will also need a power supply. If you have an old computer, you can use the power supply from it to power the radio. Yellow wire on one of the power supply ends to the red wire, and the black can go to either of the black wires.
If you are not sure, just increase the modulation with VR4. that will make the radio swing to about 20 - 25 watts.
Posted on Feb 19, 2009
It is very easily done. It is called a supertune. You do not have to change the final at all. The mosfet final modification that you have been told about does not work. Every radio comes with a modulation limiter. In your particular radio it is D-11. A small glass diode towards the top right of the compponent side of the board, next to the transformer. If you clip one side of this you modulation will automaticly increase to 85%. The other part of the mod is more complicated and you will need capacitors and other parts to accomplish this. Be sure to turn the pot next to the final all the way out to lower your dead key.
Posted on Sep 29, 2008
If you know any techs that are familiar with a Mosfet type transistor you maybe able to get about 25-30 watss from your radio.
Posted on Sep 27, 2008
What you want is a 'linear amplifier.' However, you might want to read this before looking further:
I didn't bother to look but there were kits on the market to assemble your own since the FCC prohibited the manufacture and sale of them in assembled condition.
Posted on Sep 08, 2008
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