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PA2AGA > TCPDIG 04.09.96 10:00l 143 Lines 6157 Bytes #-10897 (0) @ EU
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Subj: TCP-Group Digest 96/179A
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Subject: TCP-Group Digest 96/179A
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TCP-Group Digest Mon, 2 Sep 96 Volume 96 : Issue 179
Today's Topics:
advanced networking: Slovenia (2 msgs)
PPP/SLIP in connected AX25?
Radio Links and AX.25 backoff
TCP-Group Digest V96 #175
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Date: Sun, 01 Sep 96 10:25:27 EDT
From: Iztok Saje <s52d@s55tcp.ampr.org>
Subject: advanced networking: Slovenia
Hello friends !
High speed packet is in use for quite some time in Slovenia.
Here is a description of our projects and pointers for more information.
Anyhow, main message is that megabits/sec on packet are simple and
affordable using HAM technology - we intentionally ommited all nice
features found on commercial systems with 100+ engineer years in development.
We have MHz available: there is no need to watch every Hertz. We can do
HOME-MADE radios: let's do it !. We are not obligated to use standardized and
approved technologies: let's try our own ideas ! We can use simple technology:
let's trade last decibles for simplicity and robustness.
All mentioned systems are designed by Matjaz Vidmar, S53MV.
Most of active S5 packeteers contributed our share in building the network.
In 1989 we build our backbone using 23cm radios, wide bandwith FM (200 kHz)
and 38.4 kbit/s manchester code. This design is now obsolete, (it was based
on even older 23cm transverter). There were several redesigns in Italy and
in Croatia. It is not suggested to copy our design, we already started new
one, but abadoned it because 38.4 is too slow for today.
Anyhow, make a 23cm FM
radio, put ceramic FM filter instead of XTAL one, ignore NBFM stability
problems and radio is cheaper as narrow band FM !
There is a user 70cm WBFM radio, (200 kHz wide bandwith FM), which exists
in several incarnations: basic XTAL one and S51RM/S53RM redesign with PLL.
Schematics are available in PS format for FTP. It is based on cheap
material in Slovenia (one TV company went QRT, so we got plenty of material).
Schematics are available in .PS format for FTP. This radio is a big sucess:
home made XTAL version can be build for some US$ 100, and manchester modems
are cheaper as 3105 chip alone. There are over 200 pieces build in S5,9A,I,T9,
HA and OE. Radios are robust and simple, so even nonexperienced users
can build them. Getting on 38k4 packet in Slovenia is cheaper as 1200 bps,
if TNC and 144 MHz handie are used for 1200 bps. To keep TXDELAY low,
low AF is filtered out so radios are NOT to be used with G3RUH modems.
With medium-speed users it was necessary to upgrade backbone.
1.288 Mbit/sec 13 cm PSK links were build a year ago, and they performed
extremly well. Complete design is shown on our http page, including
PSK modem and scrambler. It is not intended for beginners - we are
using it only for hops between mountaintop nodes. They are in use
in S5 and in Italy.
Users shall build 23cm 1.288 Mbit/sec radios. This design is simpler as
13cm. We expect heavy users with clear path to local nodes to migrate
from 70cm to 23cm next year. S57BBA is still scanning the pictures, so
only english description is available on our home page. Some 20 radios are
already build or in final stage, and they perform well.
Digital side:
SuperVozelj node was developed based on 68010 CPU. 68020 version is QRV,
and we hopw to migrate design to 68360 soon. Complete schematics and
(rather old) sources are available for FTP.
Baycom USCC card was cloned with manchester modems by S51RM/S53RM. This is
now main card to run 38k4 and 76k8 bit/s on 70 cm WBFM.
S57MMK and IV3ZXF both made SCC cards with DMA. Both are in alpha phase,
and both run 1.288 Mbit/sec AX.25 packet on PC. Slightly tuned PI-card
drivers are used for S57MMK card.
Last new add on is CDD camera on SV node. It is nice to check WX on
hilltop by downloading pictures from a node. This shows ATVers what is
their future... And who needs MHz !
There are several voice-mailboxes in Slovenia. DVMS is designed by DL9MHZ.
Voice-BBSes are controled by DTMF, and they are linked over packet.
Messages up to 100 kbytes are exchanged between DVMS (Digital Voice Mail
System, I guess) using packet.
So far we are only discussing live voice over packet. It is no fun, so
nobody really started it. Maybe on some boring winter weekends we can
merge Soundblaster, GSM compression sources and TFKISS driver ?
Avaialablity:
All projects are published in Slovenian in CQ ZRS magazine.
Address: ZRS (Slovenian HAM union)
Lepi pot 6
SI-1000 Ljubljana
Slovenija
Some articles were published elsewhere, in Italy, Germany (Weinheim
conferences) etc.
We (frankly, S57BBA who is sysop of ljutcp.hamradio.si) are working
on scanning all pictures and slowly translating texts to English, so all
articles should appear there.
Check our URL http://www.hamradio.si/hamradio for progress.
13 cm PSK radio page is complete. There are some nice pictures of
To be continued in digest: tcp_96_179B
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