> Hi to all tower and antenna types...having spent some time looking at
> different rohn designs ..ie r45 nd r55 and r65...i am pomdering the chance
> of "rolling my own" ...has anyone ever done this and any suggestions???
> 1. I am thinking of designing something about the sme dimensions as
> R65...about 24' on a side ...using 1.5 in steel tubing ...60,000 psi
> tensile strength and in 10 foot lengths...using steel flanges to couple
> them together...
> 2. my goal is a 200 ft plus...ie about 250 feet high tower that will
> support a 3 el 80m yagi with a 72 ft boom..another project for later.....
> 3. suggestions would be appreciated....
>
> tnx de Rick NQ4I
>
> --
Rick, back in the 70s, when I got re-involved with radio and was
putting a station together, I just couldn't seem to scrape together
the $25 per section for Rohn 25 to put up 30 feet of tower on my
roof. Being the resourceful type in the best ham tradition (and with
a reasonably well equipped shop), I set about to build a Rohn 25
equivalent. I used TV mast and conduit, and bent the conduit around
a jig for the braces (a la Rohn 6), then drilled the conduit and
mast, and bolted the parts together. I even built a triangular apex
top section and had a friend weld it up, complete with through
tubing for mast, etc.
I put it up and installed a small VHF antenna on it, but for a
variety of reasons never put an HF antenna on it.
After I did the math some time later, I realized I had spent about
the same for it as I would have for Rohn 25, and didn't have near the
tower. Not only that, I had a bunch of labor in three measly
sections. I kicked myself for a long time over it, but I now I got to
write this story.
A large corporation has economies-of-scale issues that make their
product often far more affordable than one might first think. Also
(and I'm waiting for Steve to jump all over this part), particularly
for the sort of installation you contemplate, they have access to
engineering talent that the average amateur just does not.
I suggest that unless you have access to lots of materials, the specs
for which you have available to you, and unless you have access to
the machinery required for assembly (shop, welder) and the ability to
make jigs, and lots of time, you may be better off cruising the bands
or practicing using the logging software than "manufacturing" your
own tower.
Should you do it? Only you can answer all the questions needed for
that response. Would I do it? Not in a zillion years. Been there, done
that.
73, Rod N4SI
The DXer formerly known as N9AKE
(c) 5 November, 1996
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