M2 40 Mtr Yagi

[Don Moman]

Yes, I have noticed the exact same problem with the M2 40m yagi. I helped
another local amateur install one (at the top of a small stack, so a big
job to change it!). After FINALLY getting a decent match (that's another
story!) it was installed but within a few weeks was showing fluctuating
SWR when there was wind.

Even at the time of putting it up we didn't think using set screws on that
aluminum rod that doubles as an element support member too was a good idea
at all, and unfortunately our fears were proven. Aluminum in that
situation is just too soft and any screws are going to loosen up. The
screws won't back off - so doubling them up isn't going to do much - the
aluminum itself on the rod will flow away, and if you keep tightening I'm
sure you'll weaken and eventually they will fail (we can't reach it so he
has just "lived with it" while thinking dark thoughts about M2) 

The split bolt idea might help but I'd be inclined to try and replace
those rods with good heavy copper weld wire and keep tension on the wire
but not on the actual joint. 

73 Don

VE6JY is Don Moman               email: ve6jy@freenet.edmonton.ab.ca 
Box 127 Lamont, Alberta
T0B 2R0  (403) 895-2925



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