[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

RE: MIR transmits UNUSEFUL data !

Hi Alain

You made some good points.

However, I would like to mention that we over here in South Africa have a
fairly small number of hams, with very few interested in satellites.  I
worked Mir this morning, around 06h25 (local time).  There was only one
other station (about 600km away), and we both worked Mir without any
problems.  We each did what we wanted to do, and disconnected as quickly as

While I understand the problems in the highly congested areas, by far the
greatest portion of the earth's surface is not inhabited by any hams, or by
very few.  Those areas find the Mir PMS to be great for getting hams with
limited equipment interested in working sats.  Most of these will then
either move on to something else, or will upgrade their stations to work the
more complex/difficult sats.

Ray (ZS6RSW)

-----Original Message-----
From: owner-sarex@AMSAT.org [mailto:owner-sarex@AMSAT.org]On Behalf Of
Alain De Carolis
Sent: Friday, June 19, 1998 5:19 PM
To: sarex@AMSAT.org; amsat-bb@AMSAT.org
Subject: MIR transmits UNUSEFUL data !

Dear OM's,

I would like to say my point of view about the MIR voice/packet operations.

MIR, as everyone on this list knows, operates on 145.985 FM. Packet is 1200
Bd AFSK AX.25.
With this configuration MIR is very easy to work because the needed
equipment is very poor:  WRONG !!!

Give a see at the attached file. It is the monitor window of last MIR pass
over Europe.
Well i have counted 140 BUSY flags on 160 packets received!
This means that about 87% of the data trasmitted by MIR in a entire pass is
totally UNUSEFUL.
Noone were able to read or send a message (so what is the goal of that pms
up there?).

For who does not know what a busy means (I think that only very few people
know it when i look at the monitor window...) it means that when you receive
a "Busy fm R0MIR-1" it wants to tell you this: "I am BUSY at the moment,
could you please stand-by and wait for your turn?". People seems to ignore
this and immediately call again. Then, of course, they get again busy, so
they try again and so on.

The pass I have just recorded is not the worse. In fact the R0MIR digipeater
was turned off. When the digi is ON there are all the neighbourhood stations
saying "hello" and "how are you" to each other so the unuseful data sent
rate is close to 100%.

Voice operations are also difficult over high populated areas. In fact, for
example, just few days before coming back Andy Thomas wrote: VOICE HAS BEEN
Many of the cosmonauts do not like to the amateur radio on voice because of
the confusion wich immediately starts. They just like to have a chat, not to
manage a vk0ir-like pile-up.


The idea that a easy access station onboard MIR allows all amateurs to work
it is wrong. In fact currently only few amateurs have enought antenna gain
and enought power to pass over the "QRM" and work without problems R0MIR.
MIR is going to be destroyed in a short time. So it's too late to think
about any change.
We must think about the new ISS. I believe that a too popular amateur radio
system is not a right choice. A
less accessible one (eg. packet PSK and phone on UHF) would allow all the
really interested hams to work the space station easily, and would cut off
all the "just courious" and the trouble makers.

Please let me know what is your impressions about this. Best 73's

Alain De Carolis IZ6BYY (ex IW6PBC)
e-mail iz6byy@amsat.org or alain@mdcom.it
home page http://users.mdcom.it/alain
ICQ UIN 1870256 - PGP Public key avaiable
GSM phone +393388719952