[NLRS] Soldering elements for loop yagi

[Zack Widup]

I agree with Donn. I have built loopers for 903 and 1296 but they get use
mainly as portable antennas. They get thrown into and pulled out of the car
a lot. And sometimes I do mean THROWN. Like when I'm taking the station down
in an ice storm in the dark and just want to get everything packed up and
worry about breakages later.
But my experience with solder connections outside is that exposed to the
weather, solder deteriorates. If you coat it with paint or silicone sealant
it may last longer.

The beauty of loop yagis is that it is so easy to replace damaged loops when
they are held to the boom with screws. I've replaced several a time or two
on my loopers. Also  if they get bent out of shape while ruiding in a
vehicle, they are very easy to bend back into shape.

As Donn pointed out, any variation in the loop elements, spacing or mounting
techniques is likely to change the way the design performs. I think it's OK
to switch to copper instead of aluminum if aluminum is specified but keep
the same metal thickness and width of loop material. Copper gets corroded
quickly out in the weather unless painted; aluminum doesn't.

73, Zack W9SZ


On Tue, Jun 22, 2010 at 5:04 PM, Donn - WA2VOI/0 <wa2voi at mninter.net> wrote:

>
>
> 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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