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Audiophile73
Junior Member
Username: Audiophile73
Post Number: 17
Registered: 5-2004
| | Posted on Tuesday, October 26, 2004 - 12:09 am: | 
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ok im a little confused. I was always taught the 1 to 4 rule. So a 4 watt dk fully modulated (100%) would be around 16 watts. Ok, so if I turned down my radio to a 2 watt dk it will swing to around 8 or 10 watts. That makes sense to me, but how do these radios get a 1 or 2 watt dk and swing up to like 16 watts. How are they not over modulated. |
Audiophile73
Junior Member
Username: Audiophile73
Post Number: 20
Registered: 5-2004
| | Posted on Tuesday, October 26, 2004 - 9:28 pm: |
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o c'mon |
Patzerozero
Intermediate Member
Username: Patzerozero
Post Number: 167
Registered: 7-2004
| | Posted on Friday, October 29, 2004 - 6:45 pm: |
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there's a little screw under the wattmeter's window to adjust the zero setting. if you turn it up you can increase your output.
well i'm sure some shady tuners have tried it.
i'm sure a lot of claims are exaggerated, as well as meter tolerances/inaccuracies etc. and there's really no noticable difference in 12 or 16 watts swing or 3 or 4 watts dead key. there's fancier mods out there such as adding dual finals, changing the original final, npc-rc, if you're handy w/a soldering iron and want to see what you can do to a radio, as i do, that's all fine and dandy. but there's always someone who has more, has done it better, etc. as long as i'm loud and clear sounding locally, i fire up the ole amp to get out when the skip's rolling.
as for 1 or 2 w swinging 16 if you're referring to a standard cb, i'd take it w/ a grain of salt.
a radio such as magnums, transmit/audio was designed from the ground up to key 1 swing 40 and is probably not able to be duplicated effectively.
of course, in my experience, whatever magnum did to get that output turned it into a tvi machine, i've managed to minimize it, but it gives me more tvi problems than my 150w ar3500 and my grant xl w/texas star 350 on base. |
Inspector
Intermediate Member
Username: Inspector
Post Number: 100
Registered: 12-2001
| | Posted on Sunday, October 31, 2004 - 3:22 am: |
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The 4:1 ratio is a target that is used that gives the best wave-form without distortion or TVI, in an NPC-RC modification. This also keeps the stress level low on the semiconductors (just think how rough a 1W swinging 40W could be on a semiconductor! ) Don't forget, your stock radio is set to standards and those standards require that the manufacturer keep the signal within limits, and to do this, it requires there be a stable carier that changes little with modulation. So, without modification, just turning down the watts only results in a smaller carrier signal modulated the same ratio. Overmodulation exists when you defeat (or mis-tune) the AMC and the modulation-peaks attempt to exceed the limmits of the carier-envelope. This results in the peaks flattening, or clipping, causing audio distortion and RFI. The NPC-RC mod reduces the carrier and alows increase of the carrier when modulation is applied (similar to what happens in sideband only not too such an extent). It is best to have the modulation initially tuned to no more than 100% before performing the modification, otherwise even this modification will easily overmodulate...defeating its purpose. I hope I didn't get too technical but I think it answers your question. |
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