> As a matter of course, every 1/2 wave line I have is cut
for 25 kHz up
> from the bottom of the band.
>
> Now, does that make everyone happy? Or is there more
nitpicking to
> come?
It's actually not nit picking Ed. You use the system wisely
because you only tune where the line is exactly 1/2 wl long,
but here are some other things to keep in mind in other
situations:
If the line is a multiple of 1/2 wl sections, it becomes
more frequency selective for impedance shifts. (You used
this effect yourself for more exact tuning of the line.)
As line impedance is increasingly different than the
load impedance (higher SWR) it becomes more selective for
impedance shifts.
My objection to a dedicated "resonance" function on an
analyzer was my assumption most casual users who didn't
understand the transmission line effects or read the manual
would just pick up an analyzer, sweep up and down outside or
all over the band, and look for a reactance dip. They would
decide where the antenna was resonant based on that dip in
reactance.
They would just assume X=0 in the shack means resonance at
the antenna without confining measurements right around
resonance like you do.
By the way, any exact multiple of 1/4 wl even works for
finding X=0. It just doesn't work for finding the impedance
value without some use of math.
73 Tom
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|