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

[Tom_N2SR]

Platinum.   



      From: Bob K6UJ <k6uj at pacbell.net>
 To: Towertalk Reflector <towertalk at contesting.com> 
 Sent: Friday, October 13, 2017 3:29 PM
 Subject: Re: [TowerTalk] Fwd: Fwd: (80 Meter yagi question) Cu <=> Ag
   
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 at 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 at 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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