[Hidden-tech] Internet Access in the sticks?

[ussailis at shaysnet.com]

Since this is my "thing" I ought to make some comments:

Antennas:

Yes, a Yagi is good. Beware of the gain figures, tho. Many are pure BS.
Expect to get 12 to 13 dBi, no more. 

One thing to note is, from the marketing standpoint, having XX dB gain is
easy to acheive, since the dB scale is a relative scale. The gain figure
for everything but an amplifier MUST specify what it is relative to. dBi is
dB relative to an isotropic radiator, while dB by itself could be relative
to anything the marketing dept wants.

You will see many low cost patch antennas out there. That's what they
are...low cost. Most of them are poorly built, and have lower that
advertised gain figures. I think you can spend your $$ elsewhere.

There are some fine "dish" antennas available. A company with Pacific comes
to mind. They were Pacific Monolithics. Good, low cost stuff. You will get
lots more gain from a dish compated to a yagi. They make a full line of
these things. The 4 foot model is reasonable.

Three problems with antennas:

1. Cable. Small diameter and cheap cable has loss, lots of loss.
Additionally, the loss of cheap cable increases as time goes on. Even very
expensive, very large cable can have an unaccecptable loss over a moderate
run of 20 or so feet. An excellent workaround it to mount the radio portion
of the network at the antenna. Then you run ethernet cable down into the
house. Place the acess point radio in an upside down tupperware bin to keep
the rain out.

At WiFi frequencies you can't make the cable short enough.

A specific number. 12 feet of good quality RG-58 cable negates the gain of
a good Yagi WiFi antenna.

2. Pointing. More gain comes from sending more signal in a favored
direction at the expense of all other directions. So, more gain requires
better pointing accuracy, and a better mounting fixture. This is not
difficult with a 4 foot "dish" antenna.

3. Attic mount. Only if you have a window in the proper direction. A roof
with a bunch of snow will impart some loss.

Two-way amplifiers:

These devices are made that amplify both the receiver and transmitter side
of a WiFi connection. They work well if they are placed at the antenna. If
placed at the computer, most, in not all, of the receive side gain is lost
(the reason is technical, and may not be believed by all. However it is a
fact).

The FCC rules allow for 1 watt transmit power. Almost all WiFi cards
transmit 0.1 watt, so a 1 watt amp does a lot. It adds 10 dB to the signal,
which multiplies range by a bit more than 3 times.

If a amplifier is not used, go for a WiFi card that transmits more power.
Senao makes one that puts out 0.2 watts. BUT, when you set it up, make sure
you indicate your country as the USA. Europe only allows 0.1 watt.

A final thought. A record distance was achieved a while back for a WiFi
link that was completly within the FCC regulations. Distance was more than
120 miles.


Jim Ussailis
National Wireless, Inc.
ussailis at shaysnet.com





Original Message:
-----------------
From: Aron P. Goldman goldman at policydevelopment.org
Date: Mon, 18 Sep 2006 09:31:44 -0400
To: hidden-discuss at lists.hidden-tech.net
Subject: Re: [Hidden-tech] Internet Access in the sticks?


   ** Be a Good Dobee and help the group, you must be counted to post .
   ** Fill out the survey/skills inventory in the member's area.




--------------------------------------------------------------------
mail2web - Check your email from the web at
http://mail2web.com/ .