[RTTY] One more thought on emergency comm

[Joe Subich, W4TV]

 > None of it makes PacTOR IV imperative below 30 MHz.  None.

More generally - "none of it makes wideband data modes imperative
below 30 MHz".  Take PACTOR III/IV out of the equation.

Wideband data modes serve no *amateur* purpose below 30 MHz.  They are
are not likely to be sufficiently reliable - run the numbers for SNR,
fade margin, etc. for non AWGN circuits with interference, selective
fading and flutter and it will be clear that for reliability, over any
significant distance, wideband data modes will require power levels in
excess amateur limits and ERPs far greater than anything likely to be
generated with basic transceivers and simple, field deployable
antennas.

Reliability over long distances at HF using low power/limited antennas
requires narrow bandwidth modes.  Again, there is no justification for
wideband data modes at HF and if there ever is they should be put in
the spectrum already allocated for wideband (up to 6 KHz) modes.

73,

    ... Joe, W4TV


On 12/12/2013 12:34 PM, Peter Laws wrote:
> On Wed, Dec 11, 2013 at 11:01 PM, Bill Turner <dezrat1242 at wildblue.net> wrote:
>> If you really want to use radio to send massive amounts of health and
>> welfare data, how about getting a portable satellite internet setup? I live
>> out in the boonies where I use a system on my roof which could be made
>> portable very quickly and which could handle THOUSANDS of times more traffic
>> than amateur radio. And cheaper too.
>
> Interestingly, about 10 years ago, the ARC lovely Suburban-type
> vehicles with every imaginable radio, plus generators and appropriate
> antennas including satellite  Saw one up in Illinois.  Would *love* to
> have one ... and could probably find one because the ARC gave up on
> this model.  No idea what the problem was but when they started to get
> "old" they didn't replace them.
>
> That said, yes, I think there is too much ... not sure which word is
> right ... romanticism(?) about amateur radio's role in disaster
> situations.  There are MANY
> well-equipped/well-trained/well-disciplined groups out there, but for
> every one of those there are at *least* 10 groups of guys with hi-viz
> vests, hats, and HTs running around looking for someone to "save".  I
> do note that many of the better groups seem to be directly affiliated
> with law enforcement or fire protection services and use amateur radio
> to extend their capabilities ... as opposed to ham groups that do
> emergency work.
>
> None of it makes PacTOR IV imperative below 30 MHz.  None.
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