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Fw: [WISPA] Fw: [Ham-80211] Access control suggestions

dubose at texas.net dubose at texas.net
Fri Nov 5 20:41:45 UTC 2004


Perry wrote:
> When the storms hit Florida a few months back, in many communities the only 
> form of communication that worked was Ham radio.
> Cell phones, landlines, WiFi, and even fiber depend on copper for 
> interconnects.  Flooding and high winds will cause so many gaps in these 
> systems that they becomes unusable.  Even satellite services will fail from 
> overload.  <emphasis added> The ability of Hams to use long range
communications > modes to get traffic out of "dark" areas is enough
justification for its 
> existence.  The areas we should be looking into are superior coding and 
> modulation methods to increase data rates at lower frequencies and better ways 
> to use "middle" frequencies (like 70 cm. of 35 cm.) for longer range 
> communications.</eMphasis>
> 

The HSMM has a project looking at a high speed OFDM model modem that will
probably use a computer sound card to achieve 256kbps and perhaps a lot more and
will/might be use on 6M-1.2 GHz with standard transceivers.  The same type of
modem can be used on HF should be able to achieve greater than 400 WPM on a
poor, low signal channel.

But note that already MT63 gives you 200 WPM throughput at a -5 dB SNR on a poor
CCIR channel.  Pactor III doesn't do any better under those signal conditions.

The MT63 model no doubt can be improved on.

We are trying to imporve on the MT63 model in the LinLink group.

Walt/K5YFW





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