Yes, there's opportunity to use digital radio to augment current
communication systems to overcome local outages -- but we don't need
to duplicate the internet to accomplish this.
73,
Dave, AA6YQ
--- In digitalradio@yahoogroups.com, Harold Aaron <[EMAIL PROTECTED]> wrote:
>
> Agree with you Dave. About 99% of the time the internet is
reliable.
> The weak link however, is the ISP. For example, I live on the
coast of
> North Carolina along the Pamlico Sound. We are remote, so there
are no
> cable modems or any such hardwire connections. Our high-speed
provider
> uses microwave shots from multiple towers tied into several T-1
lines
> provided by AT&T or whoever they are now.
>
> I can guarantee you the first utility to go is the internet,
normally
> followed by power, and it does not take a hurricane to do it, just
a
> good old nor'easter will do. To keep the radios alive a have a
> whole-house generator good for about 6 days of operation. From the
> emergency/MARS aspect I can see where the internet would be seen as
> unreliable. Wasn't too reliable in New Orleans either.
>
> When the trees start to come down and the water rises you can
count on
> the landline phones and cells going out as well. What's left? Ham
> radio, that's about it. On the pointed end of the stick our 2-
meter
> repeater systems are most valuable as long as they are up.
However,
> they too are prone to failure as well, as they are installed on
> commercial towers with limited generator back-up. After that it is
> simplex FM and HF.
>
> The one aspect of ALE, and again I speak from AMRS-ALE experience,
not
> PC, is that is has managed to standardize comms among the many
> government entities involved in disaster support and recovery.
That is
> no small accomplishment when you consider the territorial toes and
> empires that were stepped on in the progress. Similar,to a lesser
> extent, as hams complaining about having to take FEMA courses that
> standardize response command and control. "We don't need no
stinking
> class!" I remember my Q codes.....
>
> When comms are available, how do we efficiently handle a large
volume of
> traffic? If you have ever worked above 80 meters on voice nets it
is
> surely not by SSB. That brings us back to this reflector - digital
> radio. The most efficient means is via digital modes - FEC error
> correction, PACTOR, GTOR, whatever the protocol, digital provides
the
> greatest chance of a message being transmitted and received without
> error, and does not waste 5 minutes transmitting call signs and
fills
> for a voice message under less than ideal conditions.
>
> "Robustness" is a good word. For a poor comm link, (generally
what you
> "expect on HF) and a signal that is 5 dB below the noise, you
might not
> expect any signal recovery. However, there are several digital
modes
> that can recover almost 100% of the transmitted data under those
> conditions. This is where ALE comes in by documenting these
differing
> conditions and providing a link across the frequency with the
greatest
> probability of success. Once the link is established, you can
resort to
> any digital or analog means to convey the information.
>
> Most interesting to remember that the initial concept of the
internet
> was for redundancy - survivability of comms following a nuclear
attack.
> Conceived by the same bureaucrats, but contracted out to the long-
haired
> wizards at AT&T - Bell Labs.
>
> I guess history repeats if we wait long enough. What was the
subject
> again?
>
> Best,
>
> Hank
> KI4MF
> NN0BBX
>
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