[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.

http://www.qsl.net/wa5bxo/

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
drains.
>
> Any help in furthering my understanding is appreciated.
>
> Thanks!
>
> 73,
> Joe
> N6DGY
>
>
> _______________________________________________
> AMRadio mailing list
> AMRadio at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/amradio





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