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[TowerTalk] An oops by my , re: What does X=0 mean

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Subject: [TowerTalk] An oops by my , re: What does X=0 mean
From: jreid@aloha.net (Jim Reid)
Date: Mon, 18 Jan 1999 08:17:51 -1000

Chad noticed my error in the followin sentence:


>>There is a given amount of resistive loss in every conductor/
>>component in any of our gadgets,  so at legal power max,  there
>>are about 9.5 amperes of peak current (about 7 amps rms)
>>flowing around in a 50 ohm circuit!
>
>If the antenna is resonant (X=0  :-), cannot you just apply
>Ohm's Law?  Such as I^2/R = P, or I = SQRT(P/R)
>I = SQRT(1500/50) = 5.47 Amps RMS, or 1.414*5.47= 7.7A peak?
>
>How do you calculate 7 Amps RMS?

Because I assumed the vswr on the line was 3:1!  
But I forgot to put that in my model discussion.

Chad's number is exactly correct for the rms current in 
a 50 ohm system.   Mismatch of 3:1 would be what I was 
to be correcting  with the antenna tuner--and managed
to omit that detail in my write up.  Sorry about that!

So with the correct current and with 1 ohm of loss,  about
30 watts would be lost to heat; 2 ohms, 60 watts,  etc.
BTW,  did you ever accidently touch the end of 
a 30 watt soldering iron used on PC boards?

73,  Jim,  KH7M



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