[FADCA] 802.11g Experment

[ptoth1 at tampabay.rr.com]

Doug....

802.11b/g operate in the Amateur Radio 2.4 GHz allocation.  802.11a 
operates in the 5.8 GHz allocation.

If you are operating under Part 15 rules, you are severely restricted 
on your power output, which will limit your range.  Under Part 15, you 
can use encryption to safeguard access to your Access Point(s) and 
your data.

Part 97 rules will allow you to operate with significantly more power 
(TPO and ERP).  However, Part 97 operation prohibits the use of 
encryption to secure authentication and keep Part 15 operators out of 
your Access Point.  That presents a "virtual impossibility" for 
Amateur Radio licensees.  Unless you can prohibit unlicensed operators 
from accessing the transmitter, you will be in violation of 97.313(e).

The ARRL's HSMM Working Group has been working for the last two years 
to get Part 97 changed to permit the use of encryption for domestic 
transmissions.  We believe this is absolutely essential for Part 97 
operations on spectrum WE hold a license for.  If you agree, write to 
Frank Butler-W4RH and let him know.  We have got to get this issue 
onto the front burner.

73 de Paul-NA4AR

----- Original Message -----
From: Doug Christ <kn4yt at yahoo.com>
Date: Tuesday, December 6, 2005 10:00 am
Subject: [FADCA] 802.11g Experment

> I, along with our county IT person, have been conducting some 
> 802.11g 
> experiments here in DeSoto County. The driving force behind the 
> experiment 
> is internet connectivity or lack there of after a major disaster. 
> Hurricane 
> Charley left most of our county without commercial power for up to 
> two 
> weeks. With no power, most end offices or other telephone devices 
> that do 
> not have long term power back ups in place die. In other words, 
> you loose 
> dial tone and data networks.
> 
> My EOC is right across the street from the main central office 
> that services 
> DeSoto County. We never lost telephone service and our T-1 lines 
> remained on 
> the air. We assumed that with the proper equipment, we could shoot 
> a signal 
> back to the EOC from field locations and provide email and 
> internet to 
> mobile command sights.
> 
> I do have a license for the 4.9 GHz public safety spectrum but the 
> equipment 
> is very expensive. Our IT person, Leonard, discovered that you can 
> install a 
> different firmware into a Linksys wireless router, that you can 
> configure 
> the router into gateways and repeaters. The firmware we use is 
> Talisman/Basic 1.1 which is Linux based. For security, we have set 
> the 
> router for MAC address verification, we turned off the SID 
> broadcast and 
> require a password for access.
> 
> 2.4 GHz requires line of sight so I needed to install an outside 
> antenna. I 
> installed a 15 DB gain vertical on top of my EOC. The antenna is 
> approximately 80 feet off the ground and provides a decent line of 
> sight for 
> many blocks around. I installed an antenna adapter to convert the 
> TNC 
> connecter to a N connector and installed  polyphaser lightening 
> protection. 
> I only used about 25 feet of low loss coax as I have a equipment 
> room 
> located in the top of the building near the base of my tower.
> 
> Results were surprising. We can connect to the router using the 
> wireless 
> connection built into a laptop for about four blocks as long as 
> you could 
> see the building..In certain cases, we could stretch the 
> connection to about 
> 1/2 a mile. If you set a wireless router up as a gateway, in other 
> words, 
> connect your computer to the router and use it as your RF source, 
> range 
> doubles if not triples using the standard rubber duckies that come 
> with the 
> router. The farthest we have connected using the gateway approach 
> is 4 1/2 
> miles. We drove out to the landfill and parked on top of the hill 
> which is 
> approximately 65 feet high. This puts us above the tree line and 
> we have a 
> clear line of sight back to my office. It worked great and I 
> believe the 
> connection speed was 11 MB.
> 
> I cannot help but wonder if we can use these routers for a  high-
> speed 
> backbone for our network. Heck, why not local access as well? You 
> mount the 
> dish on the tower, install the router in a weather proof container 
> and run 
> the power to the unit up the cat 5 cable. Some of the web pages I 
> have read, 
> claim ranges of 30 miles when used with a parabolic dish.
> 
> Doug/KN4YT
> 
> 
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