seaweedsteve <seaweedsteve@gmail.com> hath wroth:

>Although putting a client bridge up with the antenna is probably the
>optimal solution for neatness and gain, the approach you are
>considering is also workable. LMR 400 will allow you to put the
>router inside.

Quiz question: You have a 45 degree (1:1) pitched roof (this is
Vermont where they have snow). The house is 25ft wide. The roof
overhangs the walls about 3ft. Walls are 8ft high. The antenna mast
on the roof is 10ft long. How long an LMR400 coax run from the dish
antenna on the top of the mast, to somewhere useful inside (on a
desk)? Don't forget the drop loop and you can't drill through the
shake roof without trashing the roofers warranty.

Before I grind the numbers, make a guess as to how much coax and see
how close you get.

Starting at the dish antenna feed, we have 2ft of coax between the
dish feed and the pipe including a drip loop. Add 10ft for the mast.
The roof is:
1.4 * 12.5ft = 17.5ft
Going back to the outside wall is about 3ft (including the drip loop).
Down the wall to the floor (on the outside) is 8ft. Through the wall,
into the room, and back up to a desk, add another 6ft. Grand total:
2 + 10 + 17.5 + 3 + 8 + 6 = 46.5 ft
Actually, that seems a bit low. I've done something like that with
pre-cut 50ft lengths of LMR-400 and come up short.

>At .25 db loss per meter, you can run 8-10 meters of
>coax with acceptable loss.

For LMR-400 I use .23dB/meter or 0.07dB/ft. 50ft would be 3.5dB loss
which is tolerable. My objections to using LMR-400 were not because
of attenuation, but because of the difficulties handling the stuff,
going through the walls, dealing with the pigtail, and potential
water/freezing problems.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558