[AMRadio] Re: Legal limit

D. Chester k4kyv at charter.net
Tue Nov 13 04:19:07 EST 2007

> From: Thomas Adams <quixote2 at ix.netcom.com>
> Subject: Re: [AMRadio] Re:Reactor Wanted

> In the (unlikely) event of an FCC inspection, I doubt that the
> inspecting engineer is going to go with
> that sort of reasoning and observe such niceties, even tho it IS correct.
> The "right" answer in this case is the one that they tested me on for
> my (now defunct) 1st Class Radiotelephone
> license; the peak power of a carrier at 100 percent modulation is
> four times the carrier power. Anything else
> leaves too much wiggle room, and opens the door for
> lawsuits...  especially if your rig doesn't use any sort of
> processing tricks like negative peak clippers.
> This is a matter of absolutes...   and absolutes ONLY exist in
> bureaucracy and statutes. In those realms,
> reality means little or nothing. And the bureaucracy says that
> without processing, PEP equals four times
> the power of the unmodulated carrier.

With typical asymmetrical modulation with the male human voice, and the 
phase inverted to the "wrong" direction, 100% modulation of one kilowatt DC 
input would probably do well to achieve 1500 watts p.e.p.  There is nothing 
in Part 97 that even mentions 4 times carrier power.  What would the 
inspector use for SSB, since it has no carrier?  Besides, I'd bet they 
couldn't even measure the carrier power output from a lot of AM transmitters 
presently on the air.

Most likely, they wouldn't have any way to measure anything that is not fed 
by 50-ohm coax.  What if you use link coupling directly to a tuner that 
feeds open wire line, with only a pair of wires to tie the two links 
together?  Or if you feed the open wire line directly from a pick-up coil 
coupled directly to the tank?  Or what about an antenna that is connected 
directly to the tank circuit without any feedline or tuner?

My thoughts exactly,  regarding p.e.p., can be found by clicking on this 


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