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Re: [TowerTalk] Fwd: Fwd: (80 Meter yagi question) Cu <=> Ag

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Fwd: Fwd: (80 Meter yagi question) Cu <=> Ag
From: Patrick Greenlee <patrick_g@windstream.net>
Date: Fri, 13 Oct 2017 14:38:05 -0500
List-post: <mailto:towertalk@contesting.com>
...or polish the copper and coat with varnish or whatever new miracle coating replaced it.

Patrick        NJ5G

On 10/13/2017 2:21 PM, Bob K6UJ wrote:
Howie,
Thanks for the info.    I am trying to decide what material to use for a loading 
coil I will make for my 160 inverted L.  I was considering copper tubing and applying the 
silver plate stuff but now think it would be better to use aluminum tubing.
73,BobK6UJ

Sent from Yahoo Mail for iPhone


On Friday, October 13, 2017, 11:24 AM, Howard Hoyt <hhoyt@mebtel.net> wrote:

Hi Bob,

Two data points:

1) When I worked at a radio astronomy lab as a college student the
engineers there said silver plating the machined copper cavities ruined
their performance which I didn't understand at the time.

2) The broadcast equipment I maintain uses aluminum straps and tank
components in the plate cavities and running at quite high powers the
straps themselves seem to run cool, except for where they are tied to
the anodes of the 4CXxxxxx tubes.  I believe they are intended to help
pull heat away from the anode seal in that usage.

If that study is to be believed, perhaps the silver-plating thing in ham
equipment is a vestige of earlier manufacturing beliefs and techniques,
plus corroded copper is difficult to clean and looks like hell?  Based
on the study, lacquered polished copper or over-sized aluminum would
appear to be the winner for coil construction.

Howie - WA4PSC


On 10/13/2017 7:06 AM, towertalk-request@contesting.com wrote:
  >>Not trying to dispute the study but why then do amplifier
  >>companies use silver plated tank coils in their amplifiers ?

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