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PA2AGA > TCPDIG 03.04.97 02:05l 188 Lines 7910 Bytes #-10671 (0) @ EU
BID : TCP_97_28B
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Subj: TCP-Group Digest 97/28B
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Date: Wed, 02 Apr 97 21:53:05 MET
Message-Id: <tcp_97_28B>
From: pa2aga
To: tcp_broadcast@pa2aga-1
Subject: TCP-Group Digest 97/28B
X-BBS-Msg-Type: B
applies to common ham AFSK and to other modems. Ideal radio-data is done
by modulating the radio signal. (Sometimes, of course, the two methods
converge, but the typical voice ham rig is not such a case.)
Wireline modems tend to need "training" time, which slows down T/R
turnaround considerably. That's not an issue if you have a FDX backbone
link, but it clobbers access nets.
The problems with phase shift, multipath, etc., are of course duly noted.
A voice-oriented modem will work just fine, I suppose, into a wideband FM
audio modulator with a strong enough signal (FM broadcast style). But it
would be an awful waste of power and bandwidth. What's possible and what's
reasonable are, as usual, not identical.
fred k1io
___
Fred R. Goldstein fgoldstein@bbn.com
BBN Corp. Cambridge MA USA +1 617 873 3850
------------------------------
Date: Thu, 06 Mar 97 10:17:34 UTC
From: iw1cfl@iw1cfl.ampr.org (Michele Debandi)
Subject: 2000's Amateur radio (was:Benefits of AMPR IP encapsulation)
Hello everybody.
As I can see, when you try to build something in SHF you must have, other
the knowdlege, a lot of costly instrumentation.
For instance, build a 2m 5/8 antenna or a 80m CW QRP rig is feasible
even with a swr meter and a tester. Build a 13 cm requires a lot of
expensive instrumentation, that most hams couldn't access.
The s53mv's project for 1.2 Mbps link are really interesting, but
all the hams around that cuolud be interested at this have the problem
that after built the system they don't know how to align it.
For my experience there's a wide gap between microwavers (that enjoy
climb mountains with their 10 GHz ssb rigs for contests (1)) and
advanced packet radio guys.
There is a different view of amateur radio that make talking between
those group really difficult.
Packet requires wide bands, fixed and short link and new modulation
techniques,
where contesting requires narrow bands, long and temporary links, and
well estabilished modulation techniques.
But if we stop developement of new techniques (and digital techniques are
new), amateur radio will soon die, because young people will not be actracted,
or worse will be going to be a de-luxe CB.
73
Mike
(1) I'm also a V-UHF mountain climber for doing contest, and I find
this activity really fun, more than setup balky TNOS, X1j, linux and
similar stuff.
--
Michele Debandi I W 1 C F L
Internet: iw1cfl@linux1.cisi.unito.it Home BBS: I1VDM.IPIE.ITA.EU
Surface address: via Avigliana, 17 AMPRnet: iw1cfl@ik1xht.ampr.org
I-10040 Givoletto (TO) - ITALY POTS: +39 11 9947301
WWW page: http://www.cisi.unito.it/radiogw/
--
------------------------------
Date: Thu, 6 Mar 1997 09:33:58 -0600
From: "Charles Brabham" <n5pvl@texoma.net>
Subject: 2000's Amateur radio (was:Benefits of AMPR IP encapsulation)
According to Michele...
> Hello everybody.
>
> As I can see, when you try to build something in SHF you must have, other
> the knowdlege, a lot of costly instrumentation.
> For instance, build a 2m 5/8 antenna or a 80m CW QRP rig is feasible
> even with a swr meter and a tester. Build a 13 cm requires a lot of
> expensive instrumentation, that most hams couldn't access.
> The s53mv's project for 1.2 Mbps link are really interesting, but
> all the hams around that cuolud be interested at this have the problem
> that after built the system they don't know how to align it.
Don't feel alone in this! Several years ago, I bought the TAPR 9.6kb modem
kit, put it together, then realized I hadn't the instrumentation or
knowlege to align the modem so that it would be useful.
Among "RF purists", I can only claim the rather low status of an "appliance
operator". In other words, my personal knowlege of radio theory does not go
too far past the ON/OFF switch, and the ability to get different pieces of
equipment connected together in a useful configuration.
If I had to design a radio transmitter on my own, I'd have to try a
"spark-gap" design!
Older hams would know immediately what to do when faced with a problem like
I did with my un-aligned TAPR 9.6kb modem. - You simply look up a better
equipped, better educated ham in your area and ask for his assitance. He
would then act as as your "Elmer", helping get your equipment aligned, and
teaching you something of the process as he goes.
This fraternal aspect of amateur radio has fallen out of "fashion" in the
last decade, but still exists for those who are friendly and outgoing
enough to take advantage of it. You have to look harder, but it's still
there.
In earlier years, a prospective ham would be faced with much more difficult
and comprehensive examinations, and a period of study and guidance from
more experienced hams ( Elmers ) was a normal part of preparing to take the
tests.
The recent relaxation in liscensing requirements has tended to make it much
easier to get a ham ticket without any help, while greatly increasing the
number of new people taking the entry-level exams. These factors have
combined to reduce the effeciveness of the traditional "Elmer" system, from
which much of amateur radio's sense of fraternity and the framework for
effecting appropriate behaviour derived.
It's sad but true that many new hams have no feeling of "connection" to
amateur radio, and have no idea what to do or where to go when a technical
matter challenges them. They feel left out and let down. Who can blame
them?
A build-up of the "Elmer" system to bring it up to speed with current
liscensing practices is something we as hams can and should work to
achieve. It can't be "legislated" into existence.. Individual hams will
have to make individual efforts to make themselves available as "Elmers"
and as teachers for other hams. Hams who have questions and problems
related to ham radio should make an extra effort to obtain answers from
within the ham community.
>
> For my experience there's a wide gap between microwavers (that enjoy
> climb mountains with their 10 GHz ssb rigs for contests (1)) and
> advanced packet radio guys.
> There is a different view of amateur radio that make talking between
> those group really difficult.
> Packet requires wide bands, fixed and short link and new modulation
techniques,
> where contesting requires narrow bands, long and temporary links, and
> well estabilished modulation techniques.
>
> But if we stop developement of new techniques (and digital techniques are
> new), amateur radio will soon die, because young people will not be
actracted,
> or worse will be going to be a de-luxe CB.
>
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
------------------------------
Date: Thu, 06 Mar 1997 22:56:43 +0200
From: Emre Celebi <emre@mercan.cmpe.boun.edu.tr>
To be continued in digest: tcp_97_28C
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