[NLRS] Soldering elements for loop yagi

[Donn - WA2VOI/0]

Two comments:
First, Yes, they will weaken and fall off... the question is how long will it 
take ?  If its many years, who cares ?  If its one winter, you might want to 
think about something else.  A large part of the "how long" question is "what 
frequency?"  The sample is at 2.4 GHz and the loops are "small."  If you're 
looking at 902, or even 1296, the loops will be larger by (about) 2X... which 
means more stress on the joints and shorter life.   (Especially if they get 
coated in an ice storm.  Some of that might be mitigated by mounting the antenna 
"upside down," so the loops are below the boom.)  A coat of paint will also help 
the longevity by blocking UV and preventing corrosion.

Second, it depends on what design you are using.  The general rule for copying 
an antenna design is: "COPY the design."  That means DON'T make changes unless 
you have the equipment to measure the effect of the changes.  Don't use a metal 
boom if the design calls for wood; don't use 1/2" elements if the design calls 
for 1/8" ones, etc.  Scott's idea of passing the loops through the boom will 
markedly changed the resonance frequency of the loops (make them smaller by 
shorting parts to ground) UNLESS the design he copied called for that type of 
mounting AND the loops were made big enough to account for that originally. 
I've never seen a design for loopers that mounted elements that way (but I 
haven't seen them all, so who knows ?).  EVERY design I've ever seen calls for 
mounting the loops on top of the boom with bolts through the loop ends and the 
boom with nuts on the bottom of the boom.  This works all the way from 902 to 
3456 MHz with excellent results.  (Loopers tend to be a bit big to mount below 
900, and a bit too small to work with above 3546.)

Good luck, in any case.

73 Donn
WA2VOI/0


----- Original Message ----- 
From: "David Palm" <thepalmhq at gmail.com>
To: "NLRS List" <nlrs at mailman.qth.net>; "Badger Contesters List" 
<badgercontesters at mailman.qth.net>
Sent: Tuesday, June 22, 2010 9:07 PM
Subject: [NLRS] Soldering elements for loop yagi


>
>
> If I solder the elements of a loop yagi to a copper pipe boom, will the
> solder joints hold up over time out in the weather, or will they weaken and
> eventually let the elements drop off?
>
> I'm looking at a design like this:
> http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=10127
>
> Thanks and 73,
>
> David  W9HQ
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