On Mar 18, 9:26?pm, John Smith I wrote:
John Smith I wrote:

Over in RRAM there seems to be much debate on the need for HS data
communications, strange ...

Seems like in a REAL disaster, the need to xmit satellite maps of flood
areas, earthquake damage to bridges, structures, fires, hostiles?,
technical docs, medical documents/instructions/directions, signs, plans,
email, web data, etc. would be most appreciated if not desperately needed.

Perhaps, JS, perhaps, but don't rule out the established
infrastructure. Right after the 17 Jan 94 Northridge earthquake
here, FEMA folks brought in a bunch of equipment doing
pictures (in high speed, BTW) via satellite relay. One of those
uses was a revolving pan around messages shown in video
from way out of town...written in their own handwriting/printing.

HF ham bands have typical TOTAL bandwidths of 500 down to
100 KHz. Unless you've got some "4th dimension" gizmotchy
(as yet unknown to the rest of technical mankind), ya just
ain't gonna get much "high speed" on HF. The bandwidth
just does NOT exist for what you want.

Now, if you have such a marvelous ultra-minimal bandwidth
"high-speed" modulator for HF, run, do not walk to the
nearest California Auxiliary Communications Service office
and offer it to them. It ain't all that far from Stockton to
Sacramento. The ACS considers *all* forms of
communications for disasters, big or small, and will be
eager for input on miracle methods. Dinna wurra, laddie,
if ya win the Nobel Prize for it, I will volunteer to write
your acceptance speech in Swedish to deliver to KIng
Gustav and all the others in Stockholm. [a pronunciation
guide will cost extra, though]

Until then, amateur HF still has 60 to 300 WPM text data
to send teleprinter communications, even en masse via
packet. That DOES fit into the narrow confines of HF.
What is left of the telephone network after a major, major
disaster can send limited-frame-speed video like what
was done from Kuwait-Iraq in 1991, all over the low-
resolution, narrow-band circuits on the telephone system.

73, Len AF6AY



While VHF+ (satellite comms would be good!) may be suitable for some
flat terrain and moderate distances, availability of HF communications,
surely, would be a requirement in many situations

A laptop consumes VERY LITTLE power and can turn any xceiver into a VERY
powerful data transmission tool; most today would consider it a
requirement rather than a luxury.

However, PSK is highly unsuitable and the development of REAL tools
remains for the future ... new minds with up-to-date technology, methods
and skills will accomplishing this.

The future is coming ... like it or not.

JS