FW: [Antennas] Quick and Cheap

Sun, 21 Apr 2002 04:04:18 +0000

I asked this question on the rec.radio.amateur.antenna newsgroup a few 
years ago and learned that, as you say, the resistivity is MUCH higher for 
the galvanized coating. BUT - if the surface area of the galvanized surface 
is, for example 10x the surface area of a #12 copper wire and the RF 
resistivity of the copper is one-tenth, the larger surface area pipe has 
the same loss as the smaller wire. Because of the very large surface area, 
I would guess that a 1.5 inch galvanized pipe would have considerably less 
RF resistance than a #12 copper wire, therefore would work well as a radiator.

Jerry W4UK

At 10:18 PM 4/18/02 -0700, Adam Farson wrote:
>Tim,
>
>Galvanised pipe will probably be very lossy. Owing to skin effect, most of
>the RF current will flow through the zinc coating. Zinc is not famous for
>its low resistivity and will certainly degrade quite rapidly with exposure
>to the elements.
>
>You will certainly be much better off with aluminium or copper tubing (my
>spell-checker is set to UK English). Copper water-pipe will work fine.
>
>Best 73,
>Adam, VA7OJ/AB4OJ
>North Vancouver, BC, Canada
>http://www.qsl.net/ab4oj/
>Note new e-mail address:
>mailto:[email protected]
>
>
>-----Original Message-----
>From: [email protected]
>[mailto:[email protected]]On Behalf Of Tim Billingsley
>Sent: Thursday, April 18, 2002 14:42
>To: [email protected]
>Subject: [Antennas] Quick and Cheap
>
>
>How well will galvanized thin wall pipe radiate??
>
>Specifically top rails for chain link fencing(used as a vertical on 10 15 or
>20
>
>
>---