My ICOM 746PRO will only do 50 watts on peaks
regardless of carrier level. The scope pattern is
a bit goofy looking, but the on-air audio reports
are all very positive, even from old time AM'ers.
Ed, WA4NJY
--- wa3fiy@radioadv.com wrote:
> Jerry did answer the question very well but let's
> try another approach.
>
> Using a 100 watt max power rig as our base, no SWR
> foldback, no circuit breaker tripping,
> the rig can produce a max of 100 watts to a 50 load.
> That is 70.7 volts of RF to the 50 ohms.
> That's (70.7 X 70.7) / 50 or 500/50 or 100 watts.
> On CW that's fine but what about AM? On
> AM we must reduce the carrier to 1/2 voltage or
> 35.35 volts. Using P=E(squared) divided by
> R, that is 35.35 X35.35 = 1,250. 1,250 divided by
> 50 ohms = 25 watts. So the carrier power
> is as Jerry stated, 25% of the max power available.
> On AM modulation, the carrier voltage
> swings from the 35.35 volts with no modulation to 0
> to 70.7 volts under full modulation.
> Hence, the instantaneous power varies from 0 watts
> to 100 watts under modulation. I have
> noted some of the import rigs rate AM carrier at 40
> watts out. Don't know how they do that
> without creating clipping under full modulation. I
> guess maybe they do not allow 100%
> modulation. Anyone know for sure?
>
>
> 73,
>
> -Lee-
> WA3FIY
>
>
> On 30 Sep 2007 at 16:59, john ferro wrote:
>
> >
> > actually you have not helped me out - you still
> have not answered the question - whats the
> difference between an am carrier and cw carrier? if
> it's the same as some people say why on a japanese
> radio the am carrier is only 25 to 50 watts
> (depending on the radio) when the mic is keyed vs.
> 100 watts on the same jap radio cw mode keyed down -
> all assuming swr is 1? i understand the swr fold
> back issue.> From: OTAKEBI@aol.com> Date: Sun, 30
> Sep 2007 16:39:52 -0400> To: tentec@contesting.com>
> Subject: Re: [TenTec] ten tecs have 100 watts out on
> carrier??> > Yes, Mike.> Now we know what was going
> on once he explained it a little better.> I had a TS
> 180s that at had to see a perfect, flat, SWR to put
> out full > output.> Like Ten Tecs better.> Glad we
> were able to help him.> Dan/N4VET> > > >
> ************************************** See what's
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Ed Purvis WA4NJY
Amateur radio since
1963, tube-type most
of the time.
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