Digital ATV: It worked!

From: John D.

-----Original Message-----
From: [] Sent: Tuesday, November 24, 1998 5:51 PM
To:; Subject: Digital ATV: It worked!

Using a couple of IBM Wireless LAN PCMCIA cards operating on 2.4ghz, myself and Tom Askew, KB5IHI
were able to exchange Real Video files containing our callsigns and other information today at around
6:10PM CST.

The PCMIA wireless LAN cards are inexpensive. We purchased ours for less than $30 bucks each on the I
nternet. Most use either "Intergal" or "Patch" style antennas and can have range of up to 1,600 feet at

In our tests using two laptop computers, we were able to transmit successfully down to the corner about
800 feet away. We set up both laptops to run http Apache Server and the Real Media Basic Server (free
for personal use) we then configured the LAN cards to use TCP/IP protocol and simply typed in IP
addresses into web browsers. When the streams were detected, the web browsers would launch the
Real Media Players and we were able to have a QSO.

At 28.8 encoding, it was even possible to have two way (Full Duplex) QSO's but at 56K encoding the
stream broke often. The Wireless LAN cards had a rated bandwidth of 512K but much of this is taken up
by the protocol functions.

One way QSO's at virtually any encoding speed were possible, and high quality video (P5) was exchanged
out to our maximum distance. Please note that these transmissions would have been perfectly legal under
Part 15. However, as we plan to add power and high gain antennas, we took the extra step of joining the
Special Temporary Authorization of the TAPR. This will allow us to do several things that would otherwise
be illegal:

I.E. Use a frequency hopping sequence that differs from the FCC's guidelines for amateur use.

For more information: look under "Spread Spectrum"

I still believe that high speed packet networks are the best route towards Digital ATV on a wide scale,
however, we were eager to experiment with digital ATV, and to begin exploring options for networking.
These cards are very inexpensive and therefore, we tried the spread spectrum route first.

Some amateurs in the TAPR spread spectrum STA have had ranges out to 14 miles using these cards
with small power amps and gain antennas. We hope to try some of the "coffee can" ATV antennas soon
and see what kind of range we can achieve here.

Any body out there have access to a high speed 56K packet backbone that so we could try this out on
packet too?

Les Rayburn, KT4OZ

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