Very good Tom.....Yeah I guess its not really a big deal.....I just wanted
to hear how others cope with this issue. Thanks so much for you comments.
Stephanie R. Koles WX3K
wx3k at arrl dot net
http://www.qsl.net/wx3k
http://resumes.yahoo.com/wx3k/rfengineer
-----Original Message-----
From: Tom Anderson [mailto:ww5l@gte.net]
Sent: Saturday, May 25, 2002 10:49 AM
To: Stephanie WX3K
Subject: Re: [Towertalk] Mosley Pro95
Stephanie:
The Pro 95 is not the only antenna that moves off axis. I've got a Mosley
Classic 33 WARC with the 40m kit and it does the same and I've tightened
the
mast bolts both on the rotor and the antenna almost to what I think is the
breaking point. There is no known torque range to tighten them that I have
been
able to find. Also don't drill a hole in the mast and pin it with the bolt
through the rotor mast plate, that will more than likely weaken the mast and
also end up in the bolt shearing off. Everyone I've talked to said that
recentering the antenna periodically is just part of normal maintenance and
the
movement is just the antenna's and mast's way of relieving some of the wind
stresses.
**I have a suspicion my problem is with the rotor clamp bolts rather than
the
antenna mast bolts because I've seen some scarring on the bottom of the
mast
where it fits into the Ham IV, but none at the antenna mast double clamp
position.**
I even asked Norm of Norm's Rotor Service about torque specs and he said
just to
tightened them until they're "tight, you can't break them", only I've
snapped a
couple Ham IV u-bolts doing just that. I even have a Sears Craftsman
digital
torque wrench, but can't get any specs because no one seems to know the bolt
manufacturer I could write.
I just reoriented my beam a few weeks ago and its already 15-20 degrees out
of
misalignment and I tightened the mast and rotor clamp bolts until they were
squealing and felt on the verge of snapping. We have some pretty windy gust
fronts that come through North Texas in advance of thunderstorms. Winds in
our
area have been clocked in the 60+ mph range so far this spring along with a
couple tornadoes and funnel clouds already.
If you ever find any stainless U bolt or regular stainless steel bolt
manufacturers who are willing to give torque specs let me know.
Tom, WW5L
In windy North Texas
Tarrant County RACES/Skywarn member #NE-009
Cheryl, WY5H
Stephanie WX3K wrote:
> Just an update on my Pro95.
>
> http://www.wxpage.com/tower2000.htm
>
> It rules ! With a Yaesu FT-817 I consistently work what I hear and even in
a
> small pile ups. Good reports from Japan, Antartica, Europe, Russia.
>
> Great front to back ratio and directionality is good ! The antenna tunes
all
> 5 bands very well.
>
> My only challenge at this point is to keep the antenna from moving off
axis
> on the mast during 50 MPH wind gusts.
>
> Any suggestions ????
>
> Stephanie R. Koles WX3K
> wx3k at arrl dot net
> http://www.qsl.net/wx3k
> http://resumes.yahoo.com/wx3k/rfengineer
>
> --- StripMime Report -- processed MIME parts ---
> multipart/mixed
> text/plain (text body -- kept)
> application/ms-tnef
> ---
> _______________________________________________
> Towertalk mailing list
> Towertalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
|