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PA2AGA > TCPDIG 03.04.97 01:47l 208 Lines 7903 Bytes #-10671 (0) @ EU
BID : TCP_97_28D
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Subj: TCP-Group Digest 97/28D
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Date: Wed, 02 Apr 97 21:53:08 MET
Message-Id: <tcp_97_28D>
From: pa2aga
To: tcp_broadcast@pa2aga-1
Subject: TCP-Group Digest 97/28D
X-BBS-Msg-Type: B
# ->ampr # AMPR : rich@g7exm[.uk].ampr.org 44.131.164.1 BBS:GB7MSW
# ->NTS # Fun : Unix, X, TCP/IP, kernel, O-O, C++, SoftEng, Nano
########### More fun: Regional IP Coordinator Hertfordshire + N.London
------------------------------
Date: Tue, 11 Mar 1997 19:28:18 +1100 (EST)
From: Graham Broadbridge <grahamb@peachy.apana.org.au>
Subject: 2000's Amateur radio (was:Benefits of AMPR IP encapsulation)
On Sun, 9 Mar 1997, Jim Durham wrote:
> > > Has anyone ever tried running 28.8 modems over a duplex link? These
> > > modems usually have a "leased line" mode.
> >
> > A radio link is nothing like a copper link. Even a 9k6 phone modem
> > would not work at all over radio.
> >
>
> Huh? A radio link at 5KHZ FM should be *better* than a copper link.
> Phone lines have a very sharp roll-off at 3khz that 5KHZ fm does
> not have.
Telephone lines have reasonably standard characteristics when you look at
equalisation and phase relationships. A radio link suffers severe phase
distortion due to multipath, which obviously gets worse when you reach
frequencies useful for high speed networking. There are heaps of other
factors, and I'm pretty sure that Phil Karn posted a message here in the
last twelve months when this issue was last brought up. Perhaps someone
has it archived.
> Please don't say "So and so won't work". I'm interested in the reasons
> *why* you say it won't work. Did you try it?
No more than I've tried jumping off a building while flapping my arms :-)
Laws of physics, etc :-) :-)
Regards,
Graham.
--
-------------------------------------------------------------------------------
Graham Broadbridge Internet <grahamb@peachy.apana.org.au>
Senior Network Engineer AmprNet <vk2yui@gw.vk2yui.ampr.org>
Insurance Network Services P/L <vk2yui@amsat.org>
-------------------------------------------------------------------------------
------------------------------
Date: Tue, 11 Mar 1997 06:45:13 -0600
From: "Charles Brabham" <n5pvl@texoma.net>
Subject: 2000's Amateur radio (was:Benefits of AMPR IPencapsulation)
According to Tasos...
>>..........
>>This is part of my objection to "amateur telephone".. It's just one more
>>instance of the "dumbing down" of amateur radio, which is something all
>>hams should take a hand in resisting.
>Rather than working so hard to legitimize "radioless" ham radio, I would
>>much rather see the amateur TCP/IP community taking steps to educate and
>>assist each other as hams.
>>
>>73 DE Charles Brabham, N5PVL
>>Packet Radio : N5PVL @ N5PVL.#NTX.TX.USA.NOAM
>>E-Mail : n5pvl@texoma.com
>>Web : http://www.texoma.com/~n5pvl
>>
>I think that "amateur tcpip community" is the most intrested community to
>help and "educate".
The education I had in mind was related to radio use. It's nice to know how
to program, but as a ham, programming is a useless skill if you have no
familiarity with radios which would give your programming skills relevance
to the task at hand.
Of all "branches" of amateur radio, the ham TCP/IP community appears to be
in greatest need of radio (and ham) related education. There are plenty of
knowlegable hams within the amateur TCP/IP community, but I don't see them
making much effort to educate and assist their peers in radio-related
issues.. - Possibly the anti-ham and anti-packet propaganda which gets
tossed around so much within the amateur TCP/IP community has hurt the ham
TCP/IP community much more than the services it is intended to denigrate.
>NOS source code, (I think), is the only public available packet radio
code,
>and hundreds of hams improve it and make it better and also created
>intresting ideas, that other groups and commercial manufacturers learned
>and used:
Actually, there are several hams software packages which include the source
code.
I have heard of the great advantage in having *NOS source code open for
experimentation for at least five years now.. After all that time, *NOS is
not recognizably different. A few bells 'n whistles have been added, and a
primitive version of the functions of a full-service packet BBS has been
added.. Ho Hum..
It's still very unattractice software, difficult to set up properly and
decidedly NOT "user friendly". I don't know how many programmers have been
working to "improve" *NOS in all this time, but they must have been working
at cross-purposes since very little of any note has been accomplished.
Although I'd be the first to agree to the POTENTIAL offered by have a large
pool of ham programmers working with open, easily modified code, after all
this time I am beginning to understand that such potential is not good
enough, in itself.
I think that by now, we should reasonably be able to expect some rather
dramatic RESULTS.
That hasn't happened.
> Amprnet is the first Intranet
> Classless IP addressing
> Same addresing on slip interfaces to resolve net addresses
> IP encap solve security and movement (mobile IP) problems etc.
>
>This means that ham radio still give ideas and teach new technologies
>and also that non amateurs, "learned" more from AMPRNET,
>than old fashioned, fido-like, S&F, BBS dumb users-sysops.
Actually, packet BBS client/server software has left *NOS far, far behind
in development. This is one reason the new LINUX version of "FBB" BBS has
hams dropping *NOS like a hot potato.
>Is also difficult to educate about Amprnet and TCP/IP, hams if they think
that
>Amprnet is non amateur radio.
>
Exactly my point. The effort to legitimize "radioless" ham radio by a few
amateur TCP/IP devotees has damaged the reputation of all.
73 DE Charles Brabham, N5PVL
Packet Radio : N5PVL @ N5PVL.#NTX.TX.USA.NOAM
E-Mail : n5pvl@texoma.com
Web : http://www.texoma.com/~n5pvl
------------------------------
Date: Tue, 11 Mar 1997 10:32:38 -0500
From: Gwyn Reedy <gwyn@paccomm.com>
Subject: 2000's Amateur radio (was:Benefits of AMPR IP encapsulation)
I've seen a product marketed in another country which used a 14.4 phone
modem and dual radios (for full duplex) operation. Worked quite well over
normal UHF distances.
Gwyn Reedy, W1BEL
PacComm Packet Radio Systems
gwyn@paccomm.com
http://www.paccomm.com
----------
From: Graham Broadbridge[SMTP:grahamb@peachy.apana.org.au]
Sent: Tuesday, March 11, 1997 2:28 PM
To: Jim Durham
Cc: tcp-group@ucsd.edu
Subject: Re: 2000's Amateur radio (was:Benefits of AMPR IP encapsulation)
On Sun, 9 Mar 1997, Jim Durham wrote:
> > > Has anyone ever tried running 28.8 modems over a duplex link? These
> > > modems usually have a "leased line" mode.
> >
> > A radio link is nothing like a copper link. Even a 9k6 phone modem
> > would not work at all over radio.
> >
>
> Huh? A radio link at 5KHZ FM should be *better* than a copper link.
> Phone lines have a very sharp roll-off at 3khz that 5KHZ fm does
> not have.
Telephone lines have reasonably standard characteristics when you look at
equalisation and phase relationships. A radio link suffers severe phase
distortion due to multipath, which obviously gets worse when you reach
frequencies useful for high speed networking. There are heaps of other
factors, and I'm pretty sure that Phil Karn posted a message here in the
To be continued in digest: tcp_97_28E
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