[AMRadio] New link to Info on AM and legal power limits.

[Donald Chester]

And I agree that in the
> > majority of cases 1-2 dbs won't make a lot of difference.  The main
> > reason for the article is that there is a ceiling, and how we might
> > make the most of it.

One KW
> > DC input limit could easily be a rectangular wave modulated micro wave
> > with a PEP of 10KW and still be legal.

that's one example of ham experimentation the FCC killed with their pep BS: 
amateur radar

 >
> >  All I'm saying is that with a ceiling, either legal or
> > equipment, that there may be better ways to operate with less
> > distortion and bandwidth while improving the level of reception at the
> > same time.
> >
> >  I must admit that it was the legal limit that prompted me to
> > write the article since it's a little bit of a cramp in my style to be
> > forced to turn the variac down to 220 watts input to the final for a
> > carrier output of 165 watts.  Because my voice is so asymmetrical I
> > must reduce the carrier to this low level in order to stay with in the
> > 1500 watt PEP limit.

The great thing about the article is that it debunks the 375w carrier myth.  
  From  what I hear guys talking about  over t he air, you would think there 
is something in Part 97 saying the power limit is 375 watts of carrier 
output.  There is no mention of this in the regs.  I'm sure the majority of 
todays hams would not even understand the concept of why you could be 
running "illegal" power with  only 375w output.  They would simply  th ink  
the magic number 375, case closed.  For the same reason, you could run 800 w 
output and still be "legal".

I suspect it would be very difficult to measure peak power anywhere but at 
the output of a transmitter.  I have never seen a peak-reading field 
strength meter.  The ones I have seen measure average field strength (rf 
voltage).  That's why the meter stands still when  measuring AM signal 
strength (assuming you are not running controlled carrier), but the power 
output meter kicks upwards.

With SSB, the FCC inspector would have  to first measure what field field 
strength the transmitter hit on voice peaks,  then measure the output power 
that generated that field strength.  Whatever the pep happened to go up to, 
would determine the legality of the signal.  It is clearly possible that the 
same transmitter, with the plate meter kicking up  to the same readings on 
voice peaks, would be perfectly legal with one indivihial speaking, but 
"illeagal" when another operator took over the mic, hitting the same REAL 
output power levels on voice peaks.

In another technicality,  the FCC says the output power readings are to be 
taken at the "output terminals" of the transmitter.  That means, with a 
type-accepted, commerically built amplifier, you cannot take into account 
feedline losses. But with a homebrew  transmitter, I can  locate the tank 
circuit and its output terminals wherever I well please, even at the far end 
of a 300 ft. coax line running from the main unit out to the tower, with the 
last stage of the tank  circuit (translate: antenna tuner) in a box just 
under the antenna wire itself.

Don K4KYV

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