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Re: HF vs. Sats



Mike,

I think you may be on to something here.  In the past year, we have begun
installing SS radios for RTU communications; especially for that "last mile"
communication.  They are cheaper and easier to install; however,
interference can be a problem.  You don't want someone else with an
unlicensed radio (all SS are unlicensed) in your "skip zones."  These little
radios have eight different zones that can be individually eliminated and I
think there are four different "hop patterns."  Interference *has* been a
small problem, but the technician just goes to the radio (the master radio
can be configured remotely also; then the remote radio gets its programming
from the master radio) and reprograms the "skip zones."  Also, by observing
the software that interfaces with the radio, the technician can see what
skip zones are being interfered with and eliminate it.

We are also using SS technology with our newer digital microwave intsalls
that don't require multiple T1's.  The single T1 radios have just three
replaceable modules for quick downtime.  There is a 2 - T1 radio that I have
seen in a school, but I cannot remember how many modules are in them - I
think there are two additional modules.  If you had several sites that only
required a few DS0's then you could shoot to several sites DAX out your
DS0's and send the rest on up the line.  You could feed four sites with six
DS0's each.

I think with the relaxed rules for amateur operation on SS and the addition
of DSP also, we'll have our next generation of RF communications.  How about
an all-mode SS radio with built-in DSP - something like the FT-847.  Heck,
since so many made money off of Y2K, call it the FT-Y2KSS/DSP.  Now that's a
mouth full.

73,
Joel, K2SAT

----- Original Message -----
From: Mike Gilchrist <kf4fdj@AMSAT.Org>
To: Tony Langdon <tlang@freeway.apana.org.au>; <amsat-bb@AMSAT.Org>
Sent: Tuesday, February 22, 2000 6:33 PM
Subject: Re: [amsat-bb] HF vs. Sats


> Tony,
>
> At 09:57 PM 02/22/2000 +1000, Tony Langdon wrote:
> >And better techniques for transmitting voice, whetehr that be digital, or
> >analogue with the assistance of DSP technology to clean up the signal
(digital
> >might benefit more because of its more predictable waveforms).
>
> I'm going to go out on a limb, but I think our future communications will
> be based on some form of spread spectrum technology.  Since the FCC
relaxed
> the rules for amateur use of this technology, the time is ripe for us to
> begin experimentation in earnest.
>
> With mounting encroachment to the bands from fixed frequency QRM, spread
> spectrum just might be the BEST use of the bands, both for data and voice,
> in the very near future.
>
> 73, Mike
>
>
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