In a message dated 99-04-17 22:12:10 EDT, km1h@juno.com writes:
> The tower is very similar to Rohn 65, 20' sections and a 24" face.
> Triangle mounting plates with 3 bolts per leg. The legs are 2" and about
> .125" wall. Tower was part of a 3 bay 200' bcast array. No rust
> anywhere.
>
> I have straight sections and the original base section which tapers and
> terminates in a single point...forgot what the proper name is.
>
> The idea is to put up 120 or 140' with a much modified and strengthened
> KLM 3 el 80M yagi.
>
> Questions are:
>
> What is the preferred base mounting and amount of concrete? Only 18-20"
> or so will be below grade and sitting on solid rock.
I would use the Rohn 65 specs as a starting place but this is a real
engineering question. You should put some anchor rods into the rock and pour
the concrete over them to give you a bombproof base.
>
> Can I get away with only 2 levels ( 50 and 100' ) of 5/16 EHS for guys
> which will be out a full 75-80%?
>
Maybe. Probably. The Rohn 65 spec at 90 MPH has two sets of 5/16" guys
up to 130 feet.
> I plan to use a mid size prop pitch for the rotator ( worked fine for the
> original owner for 8 years) . What read out options are available these
> days? I sure dont want to regress to 1940's selsyns if I can avoid it. I
> plan to mount the rotator at the same level as the top set of guys which
> may be 20' below the antenna. The mast will be 3" x .25" SS.
>
The only other option is to send your PP to M2 and have them adapt it.
They put in a reed switch to adapt it to their digital control box. Several
people I know have done this and they are happy with the results. I think the
cost is around $500. I think they even add their industrial strength mast
clamp so you get a real nice package out of it.
> Why am I even doing this...must be getting senile!
>
Sounds like a fun project to me!
Cheers, Steve K7LXC
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