I mounted an R5 on my chimney with no problems on supporting it or from
soot from the chimney (natural gas fired equipment below) but I would
like to add a few extra details.
1. Don't even think about a yagi on the chimney! Don't do it! (Read
later)
2. A 10 ft high mast is too high, plus a vertical on top! My R5 was
mounted on a mast that extended one chimney height above the top of the
chimney.
3. I used a "foot mount" at the mast's bottom that was bolted into the
roof support members.
4. I used 3/16" wire rope or cable and turnbuckles instead of flimsy TV
banding around the chimney.
This setup was very solid and went nowhere. It survived over five years
of ice buildup with the wind that we get here in Chicago. I also hung a
small 2 meter beam beneath the R5 on the mast.
I have two ideas to offer on mounting a yagi beam on a roof.
The first is buy a roof tripod unit and solidly install it. Then one
can have beams and verticals and rotators all together.
The second idea is to do what I have done, if possible. At my qth I
have an attic dormer window which overlooks the roof of the back porch.
I've taken an A3 beam and mounted it onto a three foot section of heavy
wall tubing. This is attached to a rotator which is mounted on an
eighteen foot long 1 inch rigid conduit mast (from electrical supply
houses). To this I attached a double set of three 3/16 inch wire ropes
for guy wires. The bottom of the mast is mounted in a pivoting foot
mount bolted into the roof below. This whole assembly is erected and
taken down by employing the help of a few buddies and raising the
assembly "Iwo Jima" style. The guys are attached to eye bolts mounted
into the roof members. The whole setup is quite slick and has survived,
somehow, 10 years here in Chicago. Good Luck! frm Phil, KB9CRY
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|