[AMRadio] Re: Legal limit


jeremy-ca km1h at jeremy.mv.com
Tue Nov 13 07:45:22 EST 2007


----- Original Message ----- 
From: "D. Chester" <k4kyv at charter.net>
To: <amradio at mailman.qth.net>
Sent: Tuesday, November 13, 2007 4:19 AM
Subject: [AMRadio] Re: Legal limit


>
>> 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?


Its called a balun, and prepackaged ones of many ratios are readily 
available. Clip, clip and measure into the Bird.



Or what about an antenna that is connected
> directly to the tank circuit without any feedline or tuner?


Now, that is definitely asking for trouble. I'd hope that no one does that 
method any longer.

Bottom line is that Charlie is no more interested in an AMer that is a few 
dB over the limit than they are with anyone else running an 8877, 2 x 
3CX800, or similar amp on SSB or CW that can easily crank out 2500W.
What gets Charlies attention is the obvious troublemaker or braggart that 
thinks its cool to talk about his two 4-1000A's, 4CX5000, etc, meanwhile 
being 20 KHz wide.

Im sure we all know at least one SSB op that is running 5KW+ but has never 
been bothered. I'd have to take off my shoes and socks to be able to add up 
the ones I know of.

Carl
KM1H





> My thoughts exactly,  regarding p.e.p., can be found by clicking on this 
> link:
>
> http://www.youtube.com/watch?v=WxmUKVrT0iI
>
>
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