Re: All those walls

Peabody <waybackNO784SPAM44@yahoo.com> hath wroth:

>I'm going to need to communicate over a fairly short distance - a
>mximum of 50 feet as the crow flies, but the signal will have to go
>through a total of seven walls to get to the back porch.

Are your rooms really 6.25 ft wide?

>The house
>was built in 1972, so I assume it's just standard 2x4 studs and
>wallboard.

Well, it appears you're in Tusla Oklahoma. I dunno what they use for
building materials in tornado alley. If I believe the tornado movies,
the houses are made from kindling and cardboard. If I believe the
tornado safety web sites, the houses are made of prestressed concrete
tilt up walls. Since you want to go outside to the back porch, some
clue as to the exterior construction would be nice.

>I'm looking at a Toshiba E35-S2171 laptop which contains an Atheros
>card, and either the regular or HP Buffalo router.

I think you mean L35-S2171, maybe.

>Will either of
>the Buffalo routers work in that situation? If they both are likely
>to work, I'd just as soon get the regular router and save a few
>bucks, if that sounds reasonable.

Probably not. You may not have foil backed insulation inside the
interior walls, but you probably have it on the outside walls. If you
have lots of windows, there's some hope. However, my rule of thumb is
that anything over about 2-3 walls is a lost cause. What will happen
is that you will probably be able to find a location on the back porch
where it will work, but you will not be able to maintain the
connection as reflections and multipath conspire to ruin your day.

If you have a hip roof, you might consider installing the wireless
access point in the ceiling, so it only has one wall (the outside
wall) to go through.


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

On Mon, 04 Dec 2006 16:54:51 -0600, Peabody
<waybackNO784SPAM44@yahoo.com> wrote:

>Jeff Liebermann says...
>
> > If you have a hip roof, you might consider installing
> > the wireless access point in the ceiling, so it only has
> > one wall (the outside wall) to go through.
>
>Is it possible to just put the antenna in the attic? That
>would involve some kind of coax from the router's antenna
>connector, fished up through the wall, connecting to an
>antenna mounted in the attic. Would it be too lossy? I
>have no idea what would be involved in designing this, but I
>would think that if terminated properly, so that there are
>no reflections, it might be possible. On the other hand, it
>might depend on whether both send and receive use the same
>antenna normally.
>
>The cable run would be maybe 25 feet.

The obvious question is that if you only have to go 50ft, why not just
run 50ft of CAT5 ethernet cable to the back porch instead of 25ft of
coax cable to the attic?

25ft of coax cable is not all that lossy. The two available types are
LMR240 (about 1/4" diameter) and LMR400 (about .410" diameter). Losses
for 25ft would be about 4.3dB and 2.0dB respectively. At 50ft range,
either coax will work.

See:
http://www.fab-corp.com/home.php?cat=249
for pre-cut and connectorized pieces.

I'm not sure exactly what to recommend for an antenna. If all you
have to cover is the back porch, then some kind of directional panel
antenna will be the cheapest and easiest to install. If you have to
also cover the entire house, an omnidirectional antenna might work
best. Hard to tell from here.


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

Peabody <waybackNO784SPAM44@yahoo.com> hath wroth:

>Jeff Liebermann says...
>
> > The obvious question is that if you only have to go
> > 50ft, why not just run 50ft of CAT5 ethernet cable to
> > the back porch instead of 25ft of coax cable to the
> > attic?
>
>The back porch is just the most difficult place I need to
>reach. There are three other spots I would like to use.

So, run CAT5 to the back porch and use wireless in the other spots
(assuming they also don't go through 7 walls).

>Ok, thanks for the information. I was hoping for something
>a bit less expensive, like left-over cox Cable stuff.

Actually, satellite grade RG-6/u will sorta work. I've used it when I
needed to be cheap or creative. The 50 to 75 ohm mismatch is not that
horrible. About 1.5dB maximum. The cable loss is 15dB/100ft (about
the same as LMR-240) at 2.4Ghz so your 25ft run will have about 5dB
loss. You will probably need to make some custom pigtails from Type-F
to R-TNC or R-SMA or use multiple adapters. Thats 3/4th of your power
gone up in cable loss, but there's enough left to function on the back
porch. However, I doubt if one antenna will cover both the back porch
and the other "spots" inside the house. It really depends on the
antenna type and pattern.


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