Date: Sun, 14 Mar 93 04:30:11 PST
From: Advanced Amateur Radio Networking Group <tcp-group@ucsd.edu>
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Reply-To: TCP-Group@UCSD.Edu
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Subject: TCP-Group Digest V93 #70
To: tcp-group-digest
TCP-Group Digest Sun, 14 Mar 93 Volume 93 : Issue 70
Today's Topics:
satellite links (was: hidden transmitter
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Date: Mon, 15 Mar 1993 00:04:45 +1300
From: Steve_Wright@kcbbs.gen.nz (Steve Wright)
Subject: satellite links (was: hidden transmitter
To: tcp-group@ucsd.edu
>From: jackb@mdd.comm.mot.com (Jack Brindle)
>Subject: hidden transmitter routing
Message-Id: <9303142239.AA01248@kcbbs.gen.nz>
Date: 14 Mar 93 22:39:05 EST (Sun)
>
>>This discussion has got me wondering how to best handle full-duplex
>>operation over a path that has a long inherent time-delay relative to
>>the typical packet size. Specifically, suppose we had a high-orbit
>>satellite or (I wish) a geostationary satellite with a portion of it's
>>up and downlink spectrum dedicated for packet use in full-duplex
>>mode. This would be an ideal repeater at say 1200 BAUD rates. But when
I wish too. but at 1200 baud ?? Do you seriously think for one minute we can
make 1200 baud access available to the masses on such a small bandwidth
satellite ? You won't get a frame in edgeways! The proper way, (IMHO) 8-)
is install the network on the ground and then install a **few** satellite
512KBit streams to handle the inter state/continent traffic. It would have
to be done in the microwave bands (>>1300MHz) and it would have to have
protected access. The other method of course is spread spectrum through
the same band-pass. But I don't know of any hams using SS/CDMA on the
Microwave bands. Phil ??
>>you start looking at the quarter second delay between when a ground station
>>transmits and when its signal is detectable by other ground stations, it
>>seems to me that this inherent delay can cause some serious problems
>>at the higher BAUD rates. This is one situation that doesn't seem to
>>get that much better by virtue of having a full-duplex repeater
>>available. Wouldn't this require a fix of a different nature?
>>Perhaps some form of token bus?
Yup, FLAG the idea altogether and install bearers between major centres using
satellites. For the remote area folks maybe a single channel can be made
available to time share (1/2 hour each at a megabit is plenty I'd say.)
>
>Actually the VSAT guys already seem to have this one figured out pretty well.
before SS/CDMA was popular ....
>
>Interesting...
Yeah, I'll say! Wow! 8-()
Tony Says:
>station sees is limited to 1200 BAUD regardless of the channel usage.
>Yet we have satellites that can already do 9600 BAUD. We ought to be
>designing the next generation of packet satellites with the criteria
>that they run at LEAST as fast as 9600 BAUD and that the full
>bandwidth of the channel be available under the best of conditions.
The only best conditions under these circumstances will be when no-one is
using it! But we do need the higher rate. Go the whole Hog I say !
Regards,
Steve - ZL1BHD [44.147.2.16]
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End of TCP-Group Digest V93 #70
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