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Old July 20th 10, 07:27 PM
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First recorded activity by RadioBanter: Jul 2010
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Ok Chris...here's the deal with "swing"...it's pretty much BS. By turning the power down to 2 watts and letting the xmtr go to 10 watts is just going to cause splatter, TVI and a whole host of other problems just so you can show off to your CB buddies how much you can make the s-meter swing on thier end. Anything in excess of 100 percent modulation is a waste of power and will make you sound like ca-ca. Unless you want to be a smartass and a prick, follow the guide below.

100 percent AM modulation as far as us hams are concerned is unmodulated carrier times 4. So if you have a 375 watt "dead carrier" with 100 percent modulation you will show a peak reading of 1500 watts with modulation (ham legal limit, BTW)...so a 4 watt dead carrier...well 100 percent modulation will be 16 watts. That's with a linear response out of the modulator and final circuitry...FCC rules say 4 modulated 5 as far as wattage for CB. The AMC (automatic modulation control) does this (4 watts dead key, 5 max "swing") by providing a non-linear response out of the modulator and final circuitry combination, accomplished usually with a diode or diode and potentiometer. Removal or adjustment of these devices, along with realignment, (peaking out to coin CB terms) can acheive the desired modulation result described here. Type in CB mods into google and you'll find a bunch of stuff if you're so inclined.

To also pick another statement out from your post, "That's just one of the reasons I'm looking to amateur radio."

That's your best bet...get your ham license. Blows 11 meter away. Take it from an ex freebander who now is a licensed ham.

john

Hope that answers your question

Quote:
Originally Posted by Chris View Post
I will probably get some flames from this but here it goes. I have been into
CB radio for a number of years but don't agree with most of what I hear.
That's just one of the reasons I'm looking to amateur radio. One of the
things I often hear in CB circles is that one should turn a 4 watt AM radio
down to 1 1/2 watts and let it "SWING". How is this possible? What really
happens when you do this? I think I know. So, how much carrier should you
have for an amp or final stage with a known max output. In other words, if
it can produce 8 watts max unmodulated carrier, is a 4 watt carrier ideal?
If it produces 100 watts, is 50 watts ideal? How much "space"does it need
for proper modulation? Is there a website that explains this well? I'm an
electronics tech thirsting for knowledge.

Chris


 
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