23
June 2006
802.11
ADHOC AMATEUR COMMUNICATIONS HOW-TO
This very early draft How-To on using 802.11 AdHoc
mode to support amateur microwave communications is
courtesy of Jim Moss N9JIM with additions and editing by Bill Calderwood K1CT.
We'll update it as we take Jim's advice and implement it in our own
experiments:
1.
We've been
using the SMC HIGH POWER cards... 802.11b they are 200mW and have removable
antenna with 2 ports. One port is RX only, the other
is RX/TX. These go for about $59-79.
2.
We set them up
to a particular channel (2 or 3 seems best). Use a channel number less than six
to stay in the amateur band. Avoid channel 1 as it will QRM 13 cm weak signal
operations.
3.
Set bitrate to 1 or 2 Mbps. This is narrower signal than
802.11B's 11 Mbps or 802.11G's 54 Mbps allowing greater SNR, i.e. better DX.
4.
Run HORIZ
polarization to minimize QRM to our stations (unlicensed users are using
vertical polarization).
5.
Set the SSID
to be the same at all stations playing. THIS IS CRUCIAL! We kept forgetting to
do this! ARRL recommends using HSMM. We used 50UP during our last contest. Be
sure to use ADHOC mode. Needless to say WEP encryption (or
other encryption scheme) and MAC address filtering need to be turned-off.
6.
Set up static
TCPIP addresses and agree on them in advance. For example 169.254.0.10 for
station A, and 169.254.0.11 for station B. Do this by by right clicking on the wireless card’s icon under network
connections. Set TCP-IP properties to
the desired IP address, ex. 169.254.0.10 and netmask
ex. 255.255.0.0. Note that under RFC
3927 the class B IP address 169.254.x.x is the emerging default for adhoc
wireless networking.
7.
Open a DOS
window by going to RUN and type in "cmd"
(or launch from Programs-Accessories-Command Prompt).
8.
In the DOS
window, use the ping program to ping the other station "ping -t
169.254.0.11" (the -t means continuously).
9.
Point
antennas for best pings.
10.When you get fairly consistant pings... you
are ready to try netmeeting. Note that signal
strength does not work on the cards in "adhoc"
mode.
11.Run Netmeeting... use setup to set your name
to callsign + Grid. (insures
minimum info qso). In newer operating systems... they
no longer show netmeeting in the communications menu.
There should still be a folder in "program files" called "netmeeting". The file to run is called
"conf.exe" first time you run it will help setup the audio settings.
Note: On a standard Windows-2000 installation, Netmeeting
may be found at: C:\Program Files\NetMeeting. Recommend you create a shortcut
(right click on conf icon and respond yes to creating a desktop shortcut). Note
that when you set-up Netmeeting in Windows XP you’ll
automatically be asked to have a shortcut created. From this point on you'll be able to launch Netmeeting from the desktop icon.
12.Connect to the other station by typing his TCPIP address into the top
box.
13.A "ring" sound should ring on the other guys
computer, and he accepts.
14.You can then use the chat window to type, audio to talk, video to see
(if you have USB camera), and whiteboard, and share screens/control.
15.To end... use hangup. Note: only the first 2 stations connecting can use
audio (we don't know why). But all connecting can see chat mode and other
stuff. We also did this all together in one room to start and get familiar with
it all, otherwise... you have no chance when you go
out!
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