Mike:

Oh no. Now someone is going to have to explain ccd cams and pixels to
you, huh? Take a course!

The short course goes, "a pixel either relates to a byte, a word (16
bits) or a double-word (32-bits, or larger)--you grab the pixels from
the cam (bytes, words, etc)--you compress them, you send them, the guy
at the other end uncompress them, sends them to his video card and
views them...

Geesh, are you guys all setting around the same computer in some old
age home?

If you even mention old analog cams from some Smithsonian the guys in
the white coats will be here!

John

"Mike Coslo" wrote in message
...
wrote:
Mike Coslo wrote:

Dave Heil wrote:

wrote:


How we be gonna scale those pictures and live video to fit into
2.5 KHz?


Two steps:

1) Convert the pictures and video into highly-compressed digital
formats for transmission.

Oooh, there could be a problem there! There are limits to the
compression, and we have exceeded them in some forms already. Check
to see how many vertical pans there are on video signals lately. The
compression on the digital signals (note that even if you are
getting your feed via analog cable, you are still almost certainly
looking at a digital signal) already calls for some major aliasing.

There are limits, and there are limits. How much more are we going
to throw away?


2) Use different modes/modulations/protocols

Shannon's Theorem tells us that we can get very high data rates
through
very narrow bandwidths *if* we have adequate signal-to-noise ratio.
Note that "noise" takes many forms, not just the thermal noise
we're
used to.

What're we going to do when the data rate that we need is darn
near(or above) frequency in use?


For example, PSK has an advantage over OOK when dealing with
thermal
noise. But when dealing with other types of noise, OOK can have an
advantage. It all depends on the transmission medium. What works on
a
telephone line may not work on an HF path of the same apparent
bandwidth.


I thought that we were going to be able to send live video
and digital images on HF?


You can do that now - just need enough S/N.

Always?


Simply by hooking our computers to our rigs via the
proper interfaces.


And software.

I really didn't think it was all that simple. Why don't we get
together and pop off a live video system for say the 160 meter band.
The video would be real time, 30 fps, and otherwise like broadcast
video. Better yet, Why don't we do it at computer resolution?


Now it seems that the *idea* is that we are going to use
DRM, and we're
going to need to get more spectrum in which to use.


There are all sorts of solutions. But there's a world of
difference between people talking theory and actual
application.

I did hear that DRM was capable of doing imagery. I couldn't find
any examples tho'. And they were very vague about it.

Most of all, some folks confuse the journey and the destination.

The journey beats all.....


Does complex and newer equal better?
Sometimes. Not always.

Is analog simpler than digital?
Sometimes!

Does having a computer that attaches to the Internet
make a person a digital expert?


Some folks think so! I don't. And besides - "digital expert"
doesn't
mean someone knows much about radio.

Ain't that the truff?


I ask for enlightenment, I get invective.
Are you surprised?

Nope. It doesn't make for a very good discussion tho'.

Appears to be what there is to offer.


Now consider how effective such a person would
be trying to sell amateur radio - with or
without a code test.

They might attract others of their ilk.

I'll bet they like some of the "wonder antennas" that keep cropping
up...

- Mike KB3EIA -