[TowerTalk] Fw: 4 el. 40 M KLM - Frequency Shift

[Mark Pride]

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 at us.ibm.com

----- Forwarded by Mark Pride/Bedford/IBM on 10/11/2006 07:35 AM -----

KJ6Y at aol.com 
10/10/2006 10:34 PM

To
Mark Pride/Bedford/IBM at 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