[ARDF] One difference between 2m and 80m courses...

[Charlesscharlau at aol.com]

I've built maybe a dozen of the tape measure beams following WB2HOL's design. 
See <http://home.att.net/%7Ejleggio/projects/rdf/rdf.htm>. Every one of them 
has worked as advertised. They have an excellent F/B ratio, essentially no 
side or back lobes, and are an all-around good ARDF antenna.

It isn't quite true that they are indestructible. For instance, at the Region 
2 Championships in Ohio last month, the director element on my tape measure 
beam cracked halfway through the 2m course. It wasn't a big deal, however, 
because even a 2-element version (reflector + driven element) works well enough. 

I am working on a different design: an antenna that uses three elements and 
spacing similar to the WB2HOL design, but instead of tape measure it will use 
fiberglass rods covered in coax braid, and then covered by a tough heat shrink 
tubing. This, I believe, is similar the design used by several members of the 
Australian ARDF team. I think the fiberglass + braid will prove to be even 
more durable than the steel tape measure, and will be less affected by wind 
(which often causes the tape measure to flutter).

Right now I'm looking for a good source of thin fiberglass rod. I find lots 
of manufacturers on the web, but few distributors/retailers. Anyone know of any 
sources?

Happy Hunting,
Charles
NZ0I

In a message dated 9/20/2003 9:12:12 AM Eastern Standard Time, nss at mwt.net 
writes:

> Subj: Re: [ARDF] One difference between 2m and 80m courses... 
>  Date: 9/20/2003 9:12:12 AM Eastern Standard Time
>  From: <A HREF="mailto:nss at mwt.net">nss at mwt.net</A>
>  To: <A HREF="mailto:aa9yh at hotmail.com">aa9yh at hotmail.com</A>
>  CC: <A HREF="mailto:ardf at kkn.net">ardf at kkn.net</A>
>  Sent from the Internet 
> 
> 
> 
> I have yet to try one of those tape measure yagis.
> 
> They seem to be an excellent cure to that "Bushwhacking" problem because you
> need not fear the breaking (or even bending) of elements.
> Who here uses them and what size?  I've seen two, three, and four element
> versions.
> 
> And most importantly, what dod you think of them?
> 
> Joe WB9SBD
> 
> Matthew Robbins wrote:
> 
> >I'm designing courses for my ARDF event next week, and one of the big
> >differences between 2m and 80m struck me:
> >
> >On 80m, you're carrying this little box, so it's much easier to plow 
> through
> >yagi-eating fight.
> >
> >And that increases the options for the course designer.
> >
> >Sweet.
> >
> >[Ken and Jen: Do you have a photo of Jen's Yagi after Ft Ancient?]
> >
> >[Oh.  Just joking about the course designing.  It's going to be fun.]
> >
> >Matthew
> >AA9YH
> >Cincinnati, Ohio
> >
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