CB AMP question

4W is the maximum legal power of the unmodulated carrier... the so-called "dead key" power. Adding modulation will increase the power. Theoretically, you can legally get as much as 16W out of a transmitter. Unmodulated carrier is a LOT easier to measure.

4:1 is the MAXIMUM ratio, and to set that properly, you need a way to read the peak power. About the only way to do it is to use an oscilloscope. Anything using a meter will be reading average power, and 3:1 is about right for measuring it that way. A 4W carrier transmitter will read about 12W at 100% modulation (modulated with a sine wave).

 

Oh, I can guarantee you that the stock radio will have a MUCH cleaner signal. Follow that with a decent amp (and I can also guarantee you that it won't be $100) and you'll have a good talker.

Another dirty little secret that the guys at the CB shops won't tell you... A properly set up stock rig (and I'm talking mic gain here, nothing changed under the cover) will be heard more clearly at a greater distance than the same radio "tweaked and peaked" to 20W peak with a 2W "dead key". The reason is that much of the extra wattage isn't on the desired channel (it's just noise somewhere else).

Ever hear someone talk through a guitar "fuzz box"? That's what overmodulation sounds like. I hear it daily on channel 19.

 

Answer is yes.

 

Well this might be a tad overstated.

A properly setup radio is different than what most CB techs do to radios, Simply adding a Cap and cranking away on the modulation pot, detuning chokes is not a properly tuned radio.

Most stock radio actually have to high of output. Any tuning I do igoes nto a Motorola R2200, CB, HAM, Commerical I do not believe in cutting corners. But then I am not a fan of noise toys or echo either.

Clean and clear, and I do agree that a scope is necessary for adjusting audio am or fm.

A well tuned radio will out talk a stock radio at a distance, and be crisp and clean. If you hear a difference in the audio quality when you turn on your amp it is not tuned properly.

See a difference on a field strenght meter yes, audio should stay clean and clear.

 

Thank you; that's my point exactly.

Far too many places do a "tweak and peak" with nothing more than a wattmeter for test equipment... and not even a good wattmeter at that. Just crank everything up to 11, and now the radio puts out 30 Watts, see? MOAR POWAH!

Never mind that the audio gain is cranked to the point where people can hear the fly fart in your sleeper, and when you speak, it sounds like the microphone is shoved down your throat to your tonsils. The fact that nobody can understand what you're saying is irrelevant, since nobody cares about your (lack of) underwear.

 

Could be your radio with the RX75 just needs some adjustment, i.e. mic gain, echo. Also, don't try running a stock radio with a RM Italy amp. They don't like over 1 1/2 - 2 watts input.

 

Now that's funny!......and sadly too true! (now if anyone wants a tech that is really a tech, let me know and I'll hook you up.)

 

One that I recommend, only because I've heard a few radios he's worked on (none of them mine) is Dave at DTB Radio, Carlisle, PA. (Where I-76 and I-81 cross.)

www.dtbradio.com

Don't be confused by "The Radio Man", who you'll hear on channel 19. TRM sells cranked-to-11 radios out of the back of his van at an abandoned gas station nearby, because he's been thrown out of everywhere else. He tends to announce himself by asking for a radio check... and I respond "Overmodulated and too much echo". (He doesn't like that...)