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Rick
I for one do not love the ARRL plan.. but it is an
improvement over the existing limitation on baud rates and mixing of data, voice
and image...and it is likely the best we are going to be able to get at this
time.
__________________________________________________________ Howard S.
White Ph.D. P. Eng., VE3GFW/K6 ex-AE6SM KY6LA Website: www.ky6la.com "No Good Deed Goes
Unpunished" "Ham Antennas Save Lives - Katrina, 2003 San Diego Fires,
911"
----- Original Message -----
Sent: Friday, February 03, 2006 4:56
PM
Subject: Re: [digitalradio] Re: ARRL
proposal removes baud rate limitations on HF
There is nothing holding back such experimentation here in
the U.S.
For one thing, you don't even need to test this on HF first.
If it ever
proved to be successful on VHF/UHF in a narrow bandwidth
format, then it
could be adopted for HF use as well.
Just wishing
something technical to happen or believing that you can
have multiple
voice conversations within the ultra narrow 3 KHz or so BW
is very
unlikely due the scientific limitations. But even if current
theory was
shown to be false and a breakthrough ever occurred, it would
be easy to
test on HF.
The bandwidth proposals seem to me to LIMIT the future
possibilities for
new voice and high throughput modes on HF due to the
very limits placed
up the maximum bandwidths permitted on HF. Right now
the main limit is
baud rate.
From what the best minds in the
commercial world have been able to come
up with, we don't see any digital
voice modes that are narrow (~ 3 KHz).
While the reason for the required
move to digital was to narrow the
BW's, they are still much wider than 3
KHz if I understand the current
state of the art and while they work
fairly well under good signal
conditions, they can be a problem under
difficult conditions where older
analog signals may get through when the
digital ones do not. The move to
digital seems to be more related to
spectrum conservation.
Even though high data throughput real time modes
are difficult to work
with narrow BW signals, we should see some
improvement (and we have)
with data modes that do not have to be as much
in real time and which
have a magnitude less signalling rate throughput
needs.
I see no legal framework changes that will "free" developers to
do all
that much on HF except for the baud rate increase. But that did not
need
a sea change to implement. As you know you have made pronouncements
about this and were asked to give examples of what limitations were now
present with existing rules and you have not responded.
The one
limitation that I have been most concerned about is the ability
to mix
data/voice/(analog or digital)/ and image on one frequency. Based
upon
ARRL statements and looking at the overall plan, I am not sure if
this
will be allowed under new band plans.
Rick, KV9U
Dr.
Howard S. White wrote:
> JIm:
>
> You have made a
very good case as to why we need to experiment and
> come up with new
technologies...
>
> Instead of concentrating on all the
potential and imaginary
> negatives... which very much reflect the old
anti SSB and anti FM
> arguments...you need to look at the
positives...
>
> There are a myriad of technologies for
squeezing high baud rates into
> tiny channels... there are a myriad of
new and not so new technologes
> out there ... such as TDMA, CDMA and
Spread Spectrum...
>
> It's going to take some clever hams
to develop these into a practical
> DV system for HF on Ham
Radio...
>
> I believe that the technology is there to
allow multiple QRM free
> multiple QSO's to share a standard HF voice
bandwidth... some ham
> needs to put it together... and some ham
(likely not in the USA under
> current baud rate limited rules) will
likely do it..
>
> Equipment.. Anything Hams develop will
likely be computer based...
> maybe even sound card based as that is
the cheapest technology.... and
> it is likely that you will still be
able to use your HF transceiver....
>
> New
Modes: Stop being so negative.....Heck... new modes is what
> this Reflector is all about... Olivia, Contestia...new versions of
> DV...we welcome new modes as they improve things....
>
> I do not have all the answers.. I just know that there has to be a
> better way.....
>
> DV... has lots of potential to
give us more channel capacity with less
> QRM... we just need to legal
framework in place so that we can
> experiment with it to dispell all
those imaginary negatives....
>
>
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Other areas of interest:
The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/
DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion)
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