[Antennas] 468/Freq in Mhz

Sun Aug 23 20:46:58 EDT 2009

First, thanks to all who replied. I would appreciate more inputs.
Now, Hi Billy,
I found that your input was exactly what happened to me.
I was replacing a ground mounted 20 meter vertical made
with #14 wire. The buried ground plane (only 4 ea 1/4
wave insulated wires) and coax feed remained the same. 
When I put up the 1 inch diameter aluminum tubing the
same length as the #14 wire, the resonant frequency
was considerably lower. I had to shorten the aluminum
tubing to get it back into the 20 meter band. This confirms
your email saying the one inch tubing would be shorter for
the same freq.
I was really stumped by what had happened and I sure
appreciate your input Billy.
Take care all. Jerry N6VG

----- Original Message ----- 
From: "Billy Cox" <aa4nu at ix.netcom.com>
To: "Jerry" <n6vg at lanset.com>
Sent: Sunday, August 23, 2009 11:08 AM
Subject: Re: [Antennas] 468/Freq in Mhz
Same formula will not work. Why?
The diameter of the conductors.
Narrow, skinny ... the #14 wire
verses 
Wider, more OD ... the 1" tubing
Think of things like the outside surface area
of the #14 vs the same for the tubing ...
Not a real technical answer for now, but should
help you to 'see' why the same formula will not
be accurate for such a wide range of conductors.
Therefore, for the same frequency, the 1" tubing 
will be shorter than the #14 wire ...
73 de Billy, AA4NU
-----Original Message-----
>From: Jerry <n6vg at lanset.com>

>Hi out there,
>Is the subject formula good for both #14 wire and 1 inch
>diameter aluminum tubing? If not, please elaborate.
>Thank you. Jerry N6VG