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Oh, how do you convert from WPEP to WRMS? Does it have to be converted to
voltage and multiplied by .707? Chris "Chris" wrote in message k.net... | So let's use a typical amp rated at 100 watts AM/CW/FM and 200 watts PEP on | SSB. Assuming that the transmitter is modulated at 100%, how many watts | should the carrier be? | | Chris | "Roy Lewallen" wrote in message | ... | | Chris wrote: | | | | | | To reduce the drive power to an amplifier and make the modulation | louder. | | | | Chris | | | | I see. But reducing the carrier won't make the modulation louder, only | | more distorted. | | | | Well, let me back up a little. What I said is true if the modulation is | | 100%. | | | | But let's suppose that the transmitter is capable of only 50% | | modulation. In that case, you *can* make the modulation louder by | | increasing the amount of audio applied to the carrier. If the | | transmitter is fundamentally designed to handle 100% modulation, this | | would require only more audio gain or a "hotter" microphone. That would | | be the best way to make your modulation louder. | | | | But let's say that instead, you reduce the carrier from 4 watts to 1. | | Then the 1 watt carrier would be 100% modulated. (100% modulation of a 4 | | watt carrier takes 2 watts. 50% modulation takes only 1/2 watt, which | | will modulate a 1 watt carrier 100%.) Now you have 100% modulation of | | the 1 watt carrier. There's the same amount of transmitted audio power | | as before -- 1/2 watt --, so you're really not making the audio any | | stronger, and no one will be able to copy you any better than before. | | (In fact, your weaker signal will have more trouble getting through in | | the presence of noise or interference.) But if you're the only signal | | being heard, the receiver's AGC (automatic gain control) will react to | | your weaker carrier by turning up the receiver's gain, making the audio | | sound louder. The person receiving your signal can make your audio just | | as loud with a 4 watt carrier by manually turning up the volume. | | | | So I'll relent and say that reducing the carrier might make your audio | | sound louder -- but only if your transmitter is undermodulated in the | | first place, there's no stronger signal to control the receiver AGC, and | | if you don't reduce the carrier so much that it makes the modulation | | exceed 100%. But your ability to get through interference and noise will | | probably be reduced. | | | | Roy Lewallen, W7EL | | |
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