> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of Tom W8JI
> Sent: Monday, July 30, 2007 3:50 PM
> To: PJPilot@aol.com; amps@contesting.com
> Subject: Re: [Amps] Looking to purchase a good 6 meter amplifier
>
>
> > Would like to buy a good 6 meter amplifier that could
> > handle 40 watts of
> > drive and give me about 350 watts of AM carrier power. ie:
> > Henry 2006, or a Swan
> > Mark 6, or a TEMPO 6&2, Commander 1200, or an Acom1000.
>
> Good luck on that!
>
> Efficiency is normally somewhat less than half the peak
> efficiency in AM linear service on carrier.
>
> 350 watts of AM carrier would be about 1400 watts DC input.
> Maybe less or more, but something around there.
>
> That would require a kilowatt or so of tube dissipation, the
> rest being tank dissipation and other losses.
>
> On peaks the input power comes close to doubling, and the
> efficiency comes close to doubling. A conservative estimate
> would be 2500W input or so on peaks, which would be about
> 1400 watts PEP output.
>
> None of these numbers would be the textbook perfect case
> where the tube runs around ~73% efficiency on peaks and 36%
> efficiency on carrier, because that assumes no external
> losses and a nearly ideal class B amplifier tube.
>
> It takes a 1500W output amplifier to do 350W carrier if you
> want linear 100% modulation. (Even more headroom is needed
> with semiconductors.)
>
> 73 Tom
To just handle 100% modulation peaks on AM:
It doesn't matter what the amplifier efficiency is. The carrier efficiency
for good linear AM, carrier efficiency will be exactly 1/2 of the PEP
efficiency if the amp is set up properly to just handle 100% modulation
peaks. To handle greater than 100% peaks carrier efficiency has to be less
than 1/2 of PEP efficiency.
Carrier output power will be 1/4 of PEP output power when set up for 100%
modulation peaks.
73
Gary K4FMX
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