Reg Edwards wrote:
But NOT pure aluminium, just a few percent of copper.

Next time I'll have to remember what a purist you are,
Reg. I'll specify Aluminum 6063-T832 or some such.
--
73, Cecil http://www.qsl.net/w5dxp

Visit a farm supply house and see what they have for aluminum tubing...the
stuff they use for making racks for trucks and pickups.
wrote in message
oups.com...
Hi,

It seems that my location boasts 60 to 110 mph winds on a regular
basis. I had put up a 1/4 wavelength 20m vertical with 1/8 wavelength
radials elevated at 7 feet, with rope guys... and the wind blew it
apart like so much tin foil!

Does anyone know of a decent commercial design for less than $1000 for
a free standing 30 to 40 foot support that can take this darn wind???

Thanks,

The Eternal Squire

The pipe thread area is a point of weakness and the overlap is way to short
to provide any strength. A better alternative is aluminum tubing with .058
wall thickness.

This allows decending sizes to fit with in one another. For example a 1"
6061 T6 10 foot long has an inside diameter of .884 and a 10 foot section of
7/8" (.875) will slide right into it. This would allow an overlap of almost
4 feet providing all the strength you need.

Good luck on your next installation.
wrote in message
oups.com...
Ground system:

5 foot of 1 inch diameter galvanized iron pipe, halfway stuck in ground
with concrete.
1 inch diameter galvanized coupler
5 foot of 1 inch diameter galvanized pipe
1 inch to 3/4 inch copper reducer
1 foot of 3/4 inch copper pipe
4 tees: 3/4 inch thru vs 1/2 inch out, soldered lengthwise along
copper pipe.
an 8 foot length of 1/2 inch copper pipe soldered into each tee
tees are reinforced above and below radials with a hose clamp
coax shield connected to top of copper pipe

Radiator:
10 feet of 3/4 inch diameter copper pipe
9 foot carbon fiber fishing rod, handle epoxied and inserted into pipe
a wire is attached to copper pipe and run up to end of rod.
Hot end of coax connected to bottom of copper pipe

Ground system and Radiator are connected in-line with a PVC twist shaft
coupler designed for 3/4 inch pipe, weather sealed with epoxy. A gap
of 1 inch between pipes inside the coupler is filled with styrofoam to
prevent contact.

Rope guys are econnected to the top part of the shaft coupler, as the
middle of the shaft coupler is predicted to be weakest point.

Sure enough, a continuous wind in excess of 60 mph vibrated the shaft
coupler into 2 pieces despite the guys, the radiator then collided with
a radial, knocking a radial out of alignment and ripping apart a hose
clamp. I suspect the wind is going to finish the job overnight.

Sigh,

The Eternal Squire

Try these guys http://www.valcom.ca/welcome.html they make antennas for
coastal coast guard shore stations and military ship antennas I had one of
the 74 foot shore/vessal antennas it was a 74 feet high with a capasative
cap and worked like a hot dam. Mind you I got mine free for the taking at a
Canadian Coast Guard station that had replaced the antennas with something
bigger.
The Valcombs are used on board ships all over the world and on shore, I got
mine where the wind was blowing on average about the same as what you have
90% of the time, a typical shore station locations.
The one I had up weighed 700 lbs and required approx. 6 yard of cement and
it never even as much as moved when the wind blew. Sold mine to an amateur
in SD aka tornado alley and last I heard he lost his barn but the antenna
surived without even as much as a scratch.
Oh by the way it has a really low angle of radiation and worked fantastic
for DX, best antenna I've ever used, next to a rombic on the Artic Circle,
aka DEW LINE.

73...de ve7agw
Al


wrote in message
oups.com...
Hi,

It seems that my location boasts 60 to 110 mph winds on a regular
basis. I had put up a 1/4 wavelength 20m vertical with 1/8 wavelength
radials elevated at 7 feet, with rope guys... and the wind blew it
apart like so much tin foil!

Does anyone know of a decent commercial design for less than $1000 for
a free standing 30 to 40 foot support that can take this darn wind???

Thanks,

The Eternal Squire

All,

Thanks so much for getting back on this... I am located about 50 miles
west of Gallup, NM.
I am in a trailer park so I do not have a very large lot. Also while
my super is a nice person, amything large enough to seriously ding a
trailer if it fell would not be not okay with him. My wife also wants
to put a storage shed next to the trailer fairly well adjacent to where
I mounted my first pipe into concrete. That limits my choices further.

My YF is generous enough to allow me to keep trying with this antenna,
but she is already concerned that I put $300 into it ($175 parts and
concrete, $50 tools, $75 to hire someone who speaks propane torch) and
thinks that I should leave the design and installation to a
professional, hence my question about decent mounting for less than
$1000.

For purposes of discussion the dimension limits to be about 25 to 35
foot vertical, and about 8 foot radius for mounted radials. I am
allowed to create ground counterpoises up to 40 feet long as long as
they snake into the back lot. Severe sway is not allowed as it could
spank the trailer.

One thing I have noticed is that street lamps and telephone poles are
unguyed but have no problem with this wind. Unfortunately, I am not
close enough to either of them to use them for a mounting.

(I cannot move, I am committed to staying. I got laid off by my
company in mid-september and we moved to a place where my wife could
use her new master's degree in education... and we have to stay in this
trailer right next to her school as a condition of her employment... it
is, fortunately, low rent forced housing).

Questions:

1) Since I have an 8 foot limit for radials, could I have 1/4
wavelength helical radials for 40m that could fit into an 8 foot
length?

1a) Could I do the same helical trick for the radiator as well?

2) My base 1 inch diameter galvanized pipe is presently 2 1/2 foot into
a 2 1/2 foot cube concrete filled hole with 2 1/2 foot exposed. What
could I screw in it that would not need guying, and would not bend nor
sway in 100 mph wind, and how high could I make that?

3) If I run up a metal pipe to 20 foot and then an insulated wire from
the dirt to the top alongside the pipe as my radiator, what effect will
the pipe have on the radiating wire?

Thanks again,

The Eternal Squire

wrote:

3) If I run up a metal pipe to 20 foot and then an insulated wire from
the dirt to the top alongside the pipe as my radiator, what effect will
the pipe have on the radiating wire?


*Install the pipe.

*Build a 16-17 foot tapered radiator made from telescoping lengths of
6061-T6 aluminum tubing. See the Texas Towers site for the tubing.
E-mail me about doing the design of the radiator, I'm equipped to do
the FEA stress analysis.

*Build an aluminum adapter plate to attach the radiator to the pipe.
See any "how to" type ham antenna book which includes the construction
of yagis. Use a pair of stainless steel u-bolts to attach the adapter
plate to the pipe. Use a pair of insulated clamps to attach the
radiator to the adapter plate. These are available from DXengineering.

http://www.dxengineering.com/Section...&DeptID=21#Top

*Run ONE 16-17 foot wire to the the adapter plate but do not ground it.
Instead attach it the braid of the coax. Attach the radiator to the
center conductor of the coax. Pull the "radial wire" as far away from
the trailer as possible in some direction or another.

This arrangement would give you a "sorta" inverted L or vertical dipole
type antenna instead of a ground plane.

Thanks again,

The Eternal Squire

w3rv

wrote:

Questions:

1) Since I have an 8 foot limit for radials, could I have 1/4
wavelength helical radials for 40m that could fit into an 8 foot
length?

1a) Could I do the same helical trick for the radiator as well?

2) My base 1 inch diameter galvanized pipe is presently 2 1/2 foot into
a 2 1/2 foot cube concrete filled hole with 2 1/2 foot exposed. What
could I screw in it that would not need guying, and would not bend nor
sway in 100 mph wind, and how high could I make that?

3) If I run up a metal pipe to 20 foot and then an insulated wire from
the dirt to the top alongside the pipe as my radiator, what effect will
the pipe have on the radiating wire?


Sounds to me like you are trying to fit the wrong antenna into the
wrong space.

Can you put radials in/on the ground? Can they be longer than 8 feet then?

And finally, can you put up a dipole or other wire antenna? If so, your
wife isn't going to be too happy when she sees the cost difference
between the dipole and what you already spent on the vertical. Dunno if
you have many trees in your area or not. But a dipole can be pretty
good, esp if money is tight. I have both a dipole (OCF) and a vertical.
They both work better than each other.... at certain times. 8^)

ALso, what bands are you trying to run?

- 73 de Mike KB3EIA -

I have no trees, streelamps, telephone poles, or anything higher than a
7 foot trailer. That was why I was considering a vertical. For
practical purposes anything higher than 40 feet is forbidden and 25
foot is as high as I practically dare do. From what I understand,
dipoles are not effective below 1/2 wavelength above the dirt, but
verticals can work well fairly close to the dirt if they have to. From
what I hear inverted vees are slightly better than dipoles but slightly
worse than verticals at low altitude.

My wife really doesn't care about money as much as she cares about
waste. If I can make my setup working with the stuff I already bought
then great... At this point I am considering just throwing in the towel
and raising a 20 foot iron pipe to mount a 20 meter inverted vee...
sigh.

20m is my favorite band, followed by 40 then 30.

The Eternal Squire

I have one problem... I can only get stuff from Home Depot, about 50
miles away.

The Eternal Squire

On 5 Dec 2005 13:35:11 -0800, wrote:

I have one problem... I can only get stuff from Home Depot, about 50
miles away.

You received some good detailed advice, and dismiss it because it
isn't on the shelf at Home Depot (whoever they are, presumably a major
hardware chain that has squeezed competition out of the market place).

Gee, I can get stuff from DX Engineering and a whole lot of other US
based suppliers, and I am ~ 10,000 miles away.

Think positively, go find some solutions, select the best and
implement it.

Owen
--