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1988-04-28
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7KB
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198 lines
E METEOR SCATTERF
E INTRODUCTIONF
This program drives a Meteor Scatter station using Packet Radio UI
frames.
Packet Radio frames at 1200 Baud are much better in MS than CW or
SSB.
To take full advantage of the method, PSK modulation is strongly
recommended. An analogic Costa's Loop is the best. Beware of
digital Costa's Loop demodulator ( Ham Radio February 1987): it
needs strong signals to work.
We use here a Japanese design PSK modem with few improvements. It
uses just LM324 and few others components. It decodes perfectly
with S0 signals.
The project was published by the JAS-1 Committee of J.A.R.L. The
photocopy with modifications is available on request.
E THE RIGF
This program runs on PCs or similar.
I have compiled also a version using the 8087, but the coprocessor
here is just a luxury: computation is very limited, at least in
this version.
The TNC must be able to go in KISS mode. (See the TCP/IP package).
(Why ?..Because KISS is beautiful)
The radio side is up to you: do your best ! Any how with this
method I foresee good QSOs also with normal stations and with minor
meteor bursts.
ETHE PROTOCOLF
The protocol I propose is very simple:
The QSO is unconnected i.e. no ESABM/UAF are exchanged. Only
EUIF are trasmitted (Unnumbered Info Frames).
Messsages are trasmitted into UIs many times until the trasmission
window expires.
Two transmission windows are selectable: 15 Sec. and 30 Sec.
Experience will show wich is the best.
Of course the two stations will agree in advance about wich window
to use and also who trasmits in the Odd parts of the minute and who
in the Even one.
For instance if we agree to use 15 Sec. windows and I go on Odd
and you on Even, my TNC will send in the intervals 1..15 and 31..45
of the minute and your in the intervals 16..30 and 46..60. When
not trasmitting the program is in Receive mode. Of course our PC
clocks should be adjusted into few seconds. If not so I can take
advantage of the infos shown with received frames: UI frames are
displayed with the Odd/Even mark, so if I receive Even frames I
will set the program to trasmit in Odd windows.
───────────────────────────────────────────────────────────────────────────────
Packet Radio Meteor Scatter by I2KFX V. 1.0
───────────────────────────────────────────────────────────────────────────────
IR2VA-2=>FF6KO-5 RR r0 1
IR2VA-2=>IK1HGI RR r3 1
╔═════════╗
IR2VA-2=>FF6KO-5 RR r0 1 ║RECEIVING║
║ WINDOW ║
IR2VA-2=>IK1HGI RR r3 1 ╚═════════╝
IR2VA-2=>IK1HGI RR r3 1
IR2VA-2=>IK1HGI RR r3 1
───────────────────────────────────────────────────────────────────────────────
╔═══════════════════╗
CQ MS CQ MS de I2KFX qth Monza JN45po ║TRANSMITTING WINDOW║
╚═══════════════════╝
───────────────────────────────────────────────────────────────────────────────
┌──────────────────────────────────────────────────────────────────────────────┐
│ TX OFF Odd 30 Sec I2BJS 16:46:11 │
│ │
│ F1 F2 F3 F4 F5 F10 │
│ TX on/off Odd/Even 15/30 Sec. Dest.Call Beac.Text EXIT │
└──────────────────────────────────────────────────────────────────────────────┘
E INSTALLATIONF
For using the program you should, first of all, edit the file
INFO.QTH with your datas. The file INFO.DOC explains the meaning
of the various parameters. Name, QTH and Locator are used for
building a default CQ message. This messagge can be overwritten
during the use with other words, and, later, re-established pushing
F5. The default DESTINATION address is 'BEACON'. It can be
chanched at any time pushing F4.
Type RMS on DOS command line for running the program.
Of course you did manage to put your TNC in KISS mode first.Didn't
you? RMS is a .BAT file wich installs the clock and runs MS. If
you have the 8087 Coprocessor you might want to edit RMS.BAT end
replace MS with MS87.
EUSEF
Once run RMS, you should see the display divided in three zones.
If you own a color display theese three zones will be more evident
because of different background colors.
The bottom part is the control panel. The lower line says what can
be done with Function Keys, The upper one is the 'Status' line. MS
starts with TX OFF. F1 toggles TX On and OFF. Please, don't put
TX ON on a crowded packet frequency unless you want to be shot.
F2 toggles between Odd and Even parts of the minute.
F3 toggles 15/30 sec. windows.
F4 lets you change the destination address in the UI packet. The
source address is always your call set in INFO.QTH.
The upper part of the screen is the receiving window. All packets
correctly received by the TNC are decoded here. UI and I frames
show also if they have been received in tho Odd or Even part of the
minute in accord with F2 and F3 settings.
The middle part of the screen is the editing window. The cursor
rests where you can write a new message. The message is accepted
when you hit <CR>; Back Space lets you correct errors.
During a QSO it is easy to prepare the answer not having to watch
at the clock: the computer will take care of of trasmitting during
selected windows.
Hit F5 for re-establishing the original default message.
ECONCLUSIONF
I hope that this way of doing QSOs will give you a lot of fun, and
will make pace between computerists and DXers.
I believe that a lot of propagation fenomena in VHF and in microwaves
can be exploited with help of digital techniques. This is just a
first attempt. DSP and Spread Spectrum will do something more.
Let me know about problems and suggested improvements.
E-1I am QRV for skeds.!!-0F
73 de Pino Zollo I2KFX
Via Negrelli, 21
20052 MONZA
ITALY
Useful readings:
Meteor-burst communications bounce signals between remote sites
Electronics December 29, 1982
Read also about W3IWI experiments with PSK on 28MHz on the AMSAT
ASR.