Angela & Gary wrote:
Yes, I have heard of the existence of such a program - unfortunately,
the folks at Texas Towers have not. I emailed them approx 1 month ago
without joy. Was this program free for the using? If so, can anyone
forward it to me (or perhaps run a few numbers for me)?? Thanks again
all for the excellent suggestions/links etc.

It's a program that they will run for you on their computer.
If you want a self-supporting 16.5 ft element, just ask what
materials you need for e.g. 90 mph.
--
73, Cecil http://www.qsl.net/w5dxp




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Cecil Moore wrote:
Angela & Gary wrote:
Yes, I have heard of the existence of such a program -
unfortunately, the folks at Texas Towers have not. I emailed them
approx 1 month ago without joy. Was this program free for the using?
If so, can anyone forward it to me (or perhaps run a few numbers for
me)?? Thanks again all for the excellent suggestions/links etc.

It's a program that they will run for you on their computer.
If you want a self-supporting 16.5 ft element, just ask what
materials you need for e.g. 90 mph.
--
It's probably K7NV's program, that Torsten mentioned.

You can buy it from K7NV's website (see Torsten's posting) but Texas
Towers obviously can't copy it to you.


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

"Angela & Gary" wrote in message
...
I am planning to construct a vertical dipole array for 20m. The
electrical calculations are complete (with help from LB Cebik) and now
I'm looking for some advice on the physical construction. I'd like to
use Al tubing and find unfortunately that this is difficult to come by
locally. I will likely obtain this then from Texas Towers and therefore
the tubing lengths will be limited to 6 ft each. They do offer nesting
sizes so the real question is what diameter to utilize for the lower
most 6 ft segment (dipole being some 34 ft or so). Recalling the approx
dimensions of commercial vert antennas I've had in the past leads me to
believe that 1.25" or so would be sufficient. Comments/advice ?? I
would like to do this without guys if possible and plan on attaching the
lower-most segments to 4x4's. Thanks in advance all.

Gary
Al and emt will bend in the first good wind. I have used top rail for chain
link fences with good success. Sections are made to fit together and can be
drilled and pinned together with a bolt.

wrote in message ...
I am planning to construct a vertical dipole array for 20m. The
electrical calculations are complete (with help from LB Cebik) and now
I'm looking for some advice on the physical construction. I'd like to

Here's one link:

http://k7nv.com/notebook/id3.htm

For 20m (unguyed), the base can be thinner than 1.25". To get an idea,
look at the taper schedule for 20m yagi elements...there the center
section is often 1" or even 7/8".

I don't agree. A 20M yagi half-element is around 17 feet long, a
self-supporting 20M vertical is around 34 feet tall. In your context
he needs to look at the taper schedule for a 40M yagi to get the
drift. The stress in a fixed end cantilever beam like a vertical
antenna goes up as the square of length (stress is proportional to
WL^^2 where W is the wind load). Without actually running the stress
analysis I suspect he'll need a base tube which is around 2.000"
diameter, maybe even 2.500" diameter x 0.058 wall 6061T6 aluminum.

Torsten
N4OGW

Brian w3rv

I don't agree. A 20M yagi half-element is around 17 feet long, a
self-supporting 20M vertical is around 34 feet tall. In your context
he needs to look at the taper schedule for a 40M yagi to get the

You are right- I missed the "vertical dipole" part

Torsten
N4OGW

wrote in message ...
I don't agree. A 20M yagi half-element is around 17 feet long, a
self-supporting 20M vertical is around 34 feet tall. In your context
he needs to look at the taper schedule for a 40M yagi to get the

You are right- I missed the "vertical dipole" part

Roger that.


Torsten
N4OGW

b.