[TowerTalk] [Spam] TowerTalk Digest, Vol 73, Issue 9

[Bill Fuqua]

This is Correct except you have left out the fact that you have an 
impedance other than 50 ohms driving it at the feed point.
Your short antenna has an impedance of  R-jX and the antenna tuner combined 
with the transmission line
is feeding it with R+jX to get a match. At the feed point the voltage is 
much higher from that coming directly out of the
50 ohm coax terminal on the transmitter. The entire system of  antenna, 
feedline and antenna tuner make a resonant circuit of much higher Q! than a 
normal dipole
antenna so you have loads of circulating current.

73
Bill wa4lav

\At 08:00 PM 1/3/2009 -0500, towertalk-request at contesting.com wrote:

>I'm not buying that!  Current flow depends on impedance, R+jX, not radiation
>resistance. Your short whip runs at high voltage and low current.  There is
>lots of current in the matching network, but little gets into the antenna
>wire.  Another way to see it is that the "boundary condition" on current
>flow is that it must be zero at the end of the wire (unless there are sparks
>flying!).  Transforming back a fraction of a wavelength to the feed point,
>you're still mostly voltage and little current.
>
>A small loop antenna is the complement, mostly current and little voltage.
>
>73 & Cheers,
>Martin AA6E