In a message dated 7/3/2007 7:19:37 A.M. Pacific Daylight Time,
k0rwl@townsqr.com writes:
> The base will be a BPC25G with pier pin atop 4x4x4 concrete.
I'm not a fan of pier pin bases because of the extra work involved
temporarily guying the first couple of sections. While they're necessary for
big
guyed towers, for a tower like yours it's totally unnecessary. Sinking the
bottom of one section in the concrete is easier all the way around.
> I will be using 2 sets of GA25GD's for guying, through three GAR30s with
equalizer plates. while living on 7 acres, the power company has run the
power line through the middle of the property thus causing me to have only one
place for the tower. I am setting base and one (east) guy on level ground.
The guys to the southwest and northwest are slightly downhill from the base
requiring 3-5 feet more cable. The cables are all 120 degrees apart and the
prevailing winds here are from the wsw. I have a large grove of trees from
the
sw to the nw on the property away from the tower which may ebb the winds a
bit. While I've got engineer drawings on how the base is to be set up, I
cannot find anything on how to mount the guy anchors. Is it like the base
with
4x4x4 concrete, rebar, how is the GAR30 attached?
Unfortunately the info isn't on the Rohn online catalog. It's a CB-1
which is 2'x2'x4' deep. There is 0.7 yards of concrete in it for the end of
the
anchor rod and the rest is backfilled. There are just four #6 pieces of rebar
(3/4") vertical in the holes.
> After all of this is done the plan is to mount a Cushcraft XM240 and
TH7DXX on the tower. What is your recommendation for a mast to handle both
Depends on your local windspeed conditions (at _www.championradio.com_
(http://www.championradio.com) under Tech Notes if you don't know) and the
spacing of the antennas. Typically you'll need a steel tube around 65 kpsi
yield strength; e.g. A520 or SAE 1026. Make some phone calls to steel tubing
suppliers and you'll find someone that has it.
> and hopefully the T2X will turn it.
It's about the minimum but should be fine.
> Which antenna should go on top and approximate spacing?
I like the biggest antenna at the bottom since it's usually the one
that'll need future maintenance and being at the bottom will make it easier to
get it up and down if necessary. An additional 8 or 10 feet of height is just
a
small percentage of wavelength and doesn't have much effect on the arrival
and take-off angles.
I've used 402CD's as close a 6 feet but more is better. Ten feet would be
FB.
Cheers & tnx for your kind comments,
Steve K7LXC
TOWER TECH -
Professional tower services for hams
Cell: 206-890-4188
************************************** See what's free at http://www.aol.com.
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|