In a message dated 4/5/02 8:36:55 AM Pacific Standard Time, w5vx@hiline.net
writes:
> 1. I stacked a Cushcraft XM240 at 131' and Force 12 C3E at 120 feet. I used
> the rule of thumb that the stacking distance should be at least 1/2 the
boom
> length of the higher frequency antenna. (C3E has a boom of 18 feet). This
is
> not a good rule of thumb for these two antennas. Both the XM240 and the C3E
> were significantly detuned from the specifications. The 120' tower has
> non-conductive guys on the top three sets so that couldn't have been the
> problem. We turned the C3E 90 degrees from the XM240 and both antennas play
> fine. Not my favorite idea but it works.
Yes, I had the same problem with the XM240 and a TH11. Turning them 90
degrees made it WORSE so we tried to get distance between them - it helped.
Using 'conventional wisdom' (old wive's tale?) of 1/2 the boom length
doesn't really work as you found out. F12 wants 12 feet spacing for their
antennas which seems to be more helpful.
>
> 3. Watching a professional tower company put up the tower and antennas was
> an education. Five guys put the tower up in about 6 hours and 2 guys put
the
> antennas up in about 2.5 hours. Then plumb and tension. It's really great
to
> know what your doing. Even with these guys who obviously know their stuff,
> one fellow accedentally dropped a come-along. Fortunately, it only hit the
> guy below him a glancing below. (Three stitches in the top of his head.)
I don't consider it a "real" tower day until I'm bleeding - hi. It's all
banged up fingers though.
>
> 4. I have been planning this project for several months. Probably the
single
> greatest planning help was "TowerTalk". This is really a great resource!
>
You're welcome! Glad it was so helpful.
Cheers,
Steve K7LXC
|