M2 40 Mtr Yagi

[Jay Terleski]

John Brosnahan wrote:
> 
> I have just experienced a similar problem with my 4L M^2 antenna
> (intermittent SWR variations and non-beam performance) and I
> will be taking it down tomorrow to repair/modify it.  I have been in
> contact with Mike, K6MYC, about the issues and options for mods
> (a couple of weeks ago) and have forwarded along copies of the relevant
> messages.
> 
> For the short term, I will either 1) make new shorting bars today that are
> split and cross bolted to make a clamp contact with a large surface
> area  or  2)  make some aluminum rod hairpins to replace the shorting bar
> (or in addition to) and attach with split bolts.   I have seen aluminum split
> bolts but I may not be able to find enough of the right size on a Saturday
> to do the job.  If I use copper ones I will wrap the linear loading rod and
> hairpin with some aluminim foil before applying the split bolts--making the
> aluminum foil the sacrificial part of the joint (plus use one of the OX-Gard
> type products).  May consider doing the job with some small stainless steel
> hose clamps if they will go down that small in size.
> 
> Any TIG weldingor anything else on the linear loading (and top guy) is sure
> to make them more prone to breakage.
> 
> 73 John
> 
> John Brosnahan   W0UN
> 24115 County Road 40
> La Salle, CO 80645
> 
> Log Padding is a NON-CONTACT sport!  (W0UA)
> 
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Send me your FAX # and I will send you the templates of how I fixed mine
3 years ago and havn't had a failure since.  I have two 2 ele jobs and 
they both went intermittent within the first 3 months.

I also designed a hairpin match which makes matches them, its included 
in the FAX.

Mike Stahl to this day denighs that he ever had a problem with these 
beams.  

I have sent my mods to at least 8 hams in last 2 years.

Jay WX0B


--
FAQ on WWW:               http://www.contesting.com/towertalkfaq.html
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 K7LXC@contesting.com
Sponsored by Akorn Access, Inc & KM9P