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Topband: Re: Element grounding

To: "Tom Rauch" <w8ji@contesting.com>, "Martin" <dl1iaq@gdxf.de>,<topband@contesting.com>
Subject: Topband: Re: Element grounding
From: "Ford Peterson" <ford@cmgate.com>
Date: Sun, 11 Apr 2004 17:12:47 -0500
List-post: <mailto:topband@contesting.com>
Tom,

Thanks for the input.  I agree with you 100%.  But I'm not going to ground them.

The housing that holds the stepper motor looks like a vacuum formed two piece 
arrangement.  The thing is sealed up pretty tight.  Air is allowed to pass 
through foam pads in the element tips.  The elements are spooled up on two 
separate spools.  The tape runs through a brush that is really 4 separate 
contacts on each tape.  The contacts are what appears to be the same material 
the elements are made of, but round like 1/8" rod.  4 of these are welded to 
the tips of a spring that looks like the letter "H".  Grounding the elements 
would not be a big deal.  Imagine the letter H illustration.  A screw passes 
through the cross member between the vertical portions of the "H".  There is 
one brush on each tape with a wire between them on the parasitics, and of 
course the balun / transformer on the driven.  The easy fix would be a wire 
from that jumper, outside the waterproof housing, and attached to the boom.  
Copious amounts of silicone should seal it back up.  Unfortunately, that wire 
will be approximately 8" long and will not be balanced.  I have no idea what 
that would do.  The direct connection would be straight through the cover of 
the housing (maybe 2" long but balanced) and no longer waterproof.

I considered much of the information you provide here.  I even confronted the 
boys at FM directly.  I think that until it becomes a problem for somebody 
(I've monitored the SteppIR reflector on yahoogroups for almost 2 years and no 
mention in my memory), the FM boys are not going to change it.  I considered 
mods myself.  For various reasons, I've decided to just leave it.  I may be 
sorry.  But so far so good.

#1 - I assume a modification would void their 4 year warrantee.  
#2 - the mod could introduced imbalances that cause more problems than cure
#3 - the 'fix' in the event of a failure is not that expensive.  Not much 
different than a run of feedline.

Ford-N0FP
ford@cmgate.com


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