Thanks guys for all this quick help.
I received input from KJ6Y and N8CC.
N8CC:
Mark,
I've put up a couple of these, as well as building a "clone" for
myself. The problem is almost certainly a broken linear loading
joint where it attaches to the "split" in one of the elements. I
ended up using coax braid to replace the last few inches of 3/8"
aluminum tubing before the connection. Due to the dissimilar
tolerance for "flex" between the element proper and the linear
loading, the smaller tubing always loses.
73,
Jeff - N8CC
KJ6Y writes:
Mark,
I'm sure the reflector and director will need tightening also. Be sure to
clean up under the screw heads and nuts and where the linear loading piece
touches. I use a small rectangular file to clean them, apply penetroc and
retighten.
Skip, KJ6Y
Check the connections on the elements where the linear loading attaches by
the fiberglass insulator, Very common problem. Conections get loose and
corrosion gets under the nuts and washers. I've repaired many of these.
Skip, KJ6Y
Post-Op K1RX:
What I found was a sheered screw that supports the inner loop of the
linear loading point at the fiberglass break on one element. Did not have
a same size screw but did have a larger one, so re-drilled the piece and
inserted the replacement screw, with penatrox, lock washers (all as it was
before). Testing prior to this repair showed a 1:1 SWR at 8.060 MHz, now
moved to the center of the 40 M band after repairs.
All this was done on the tower at 100 ft. by tilting/twisting the yagi
until one could reach the element section in question about 20 ft. down (2
man job). 3 hours to get most of the various points for retightening of
hardware, etc.
Last spring the antenna experienced a day of very high winds (70 mph) and
as a result, damage to this one screw was caused and triggered the
intermittent problem. This antenna, as we all know has too many moving
parts. Eventually another antenna will be put up in its place.
Thanks all for the help on this reflector - without a doubt, the best
resource on the net!
73, Mark, K1RX
Regards,
Mark Pride
IBM Solution Sales Executive
Strategic Alliances - Sprint/Nextel
Office: 1-877-599-2663
Mobile: 603-231-8965
email: mpride@us.ibm.com
----- Forwarded by Mark Pride/Bedford/IBM on 10/11/2006 07:35 AM -----
KJ6Y@aol.com
10/10/2006 10:34 PM
To
Mark Pride/Bedford/IBM@IBMUS
cc
Subject
Re: [TowerTalk] 4 el. 40 M KLM - Frequency Shift
Mark,
I'm sure the reflector and director will need tightening also. Be sure to
clean up under the screw heads and nuts and where the linear loading piece
touches. I use a small rectangular file to clean them, apply penetroc and
retighten.
Skip, KJ6Y
Communications Service Co
818-887-3569
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