Bill Smith wrote:
There is plenty of reason to allow AM operation at 1000 watts carrier output. Carrier serves to strongly reduce or eliminate background noise and provide a comfortable communications environment. AM was severely short-changed by the 1500 watt PEP regulation. AM stations are now restricted to only 350 watts carrier.
*IF* you're talking in a sine-wave, and have no distortion, your modulated signal is 4x the carrier. So, for 1500w PEP, your carrier should be set to 375w.
Of course, we don't speak in sine-waves. The human voice is a most complex range of frequencies, and if your speech equipment is properly setup, with attention paid to audio phase from the microphone to the modulator, with no /distortion/, I -guarantee- you will have better than 100% modulation. Meaning, your negative peaks hit the base line, your positive peaks will be beyond the 2:1 ratio of audio peaks to carrier base-line.
John/WA5BXO, Bacon and Don/K4KYV wrote a nice article on *asymmetrical audio*. Google for it.
Your 350w carrier might be being modulated beyond 100%. if it's only 100%, then it's at 1400w PEP. If your SR is 3, then that's 3db more than 1400, or effectively 2.8kW PEP. Mind you, the modulator has to have enough B+ on the plates of the tubes to produce the proper amount of audio to faithfully reproduce your voice, without distorting the audio peaks. John/BXO found out a long time ago, that in order to properly modulate his 1kW DC Input rig, he had to have (4) 813's in push-pull parallel to modulate a pair of 304TL's. On the surface, you're saying 'holy jeeze, (4) 813's in a MODULATOR?" but that's what it took to have the audio equipment faithfully reproduce his peaked, nasally, east Texas Twang riddled voice. And, man does that rig sound GOOD. John's biggest problem now is (other than finding time to get on the air, what with two boys in scouts, school activities, his wife, and running a successful business!) that in order to keep the output to 1.5kW PEP output, he can't run no more than about 220w of carrier output.
Are you sure -you- know how much PEP your rig is running, without distorting/flat-topping the peaks?
-- 73, etc -Geoff/W5OMR ______________________________________________________________ AMRadio mailing list List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net To unsubscribe, send an email to [EMAIL PROTECTED] with the word unsubscribe in the message body.
