[AMRadio] AM Power Level

Bob Bruhns bbruhns at erols.com
Sun May 18 22:59:51 EDT 2003

Hi Joe,

Generally for 100% positive modulation, 1500W PEP translates
into a 375Watt carrier.  (These are output levels.)  But in
the real work=ld, this ain't necessarily so...  Check
WA5BXO's website, there is some interesting reading on AM
power regarding carrier and modulation vs. PEP.


In particular on John's WA5BXO site, check AM Tech Page,
Natural Asymmetrical Modulation, and Amplitude Modulation
and PEP.

  Bacon, WA3WDR

----- Original Message -----
From: <N6DGY at kirtland.com>
To: <amradio at mailman.qth.net>
Sent: Sunday, May 18, 2003 1:14 PM
Subject: [AMRadio] AM Power Level

> I'm a new subscriber to the list, and I have not
discovered the way to do a search
> through the old archives.  Forgive me if this has already
been covered.
> I'm currently in the process of collecting the parts to
build a Class-E Am transmitter
> and Class-H modulator for 75 meters.  (I was quite
surprised at the relative
> simplicity of the circuit!)  While I have been a
boatanchor collector for years, and
> also an on-and-off-again Electric radio subscriber (though
I have every issue) I have
> never yet been on the air in AM mode.  Listening on 75 off
and on over the years
> has me itching to finally change that.
> I'm interested to know if I understand the newer FCC power
guidelines correctly and
> how peak power on AM is measured.  The FCC now stipulates
1500 watts peak
> output.  Am I correct in understanding that in AM, the
peak output at 100%
> modulation is four times the carrier level?  Does this
mean that if one is to be strictly
> within the FCC rules, you can have a carrier of only 375
watts in the AM mode?
> My proposed transmitter will be capable of a unmodulated
600 watt carrier.
> Fortunately, it appears to be a simple matter to reduce
power in a Class-E amp just
> by lowering the supply / modulation voltage to the MOSFET
> Any help in furthering my understanding is appreciated.
> Thanks!
> 73,
> Joe
> _______________________________________________
> AMRadio mailing list
> AMRadio at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/amradio

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