[amsat-bb] Re: ISS & Amateur Voice Comms (R
ka1rrw at yahoo.com
Mon Jun 4 15:30:01 PDT 2007
Cross Band FM Repeaters:
These are fun devices. We had a 440 repeater (mono
band) on Mir that was very popular.
And we have been able to on occasions enable the cross
band mode on the Kenwood D700, which was also popular.
There are a few issues with cross banding that need
to be weighed against the popularity.
A typical mobile rig in cross band mode can not handle
the high duty cycle of that mode for extended periods
of time. Even if you set the power to 5 watts, it
would be transmitting continuously for 20 minutes
straight as it passed over the USA and Western Europe.
In space we do not have convection cooling, hot air
does not rise. All electronics in Space on ISS will
run much hotter than on Earth. For this type of job
you will need commercial or similar equipment designed
for 100% duty cycle and it needs to operate with the
heat dissipation limitations of zero gravity inside
ISS. We already had an Alleged-overheating problem
with one radio on ISS and that was at less than 40%
Some countries doe not allow hams to have access to
440, which is why most of the ISS projects are being
designed as Mono band projects.
We are short on physical space. No room for big
If some group has the time, effort and Money, they
could try to submit a project proposals for a
repeaters. Here are some ideas that may be receptive
440 uplink, 10 meter down link repeater or visa versa:
Benefits, Only minimal band pass cavities will be
needed (all transmitters need to exceed commercial TX
We have an unused 10 meter antenna presently and 3 440
antennas on the Service module.
440 mono band repeater:
Uplink on 435.bottom of band and Downlink on 437.top
end of band. (Satellite band on 440 is 435.000
438.000). for the Mir project the DLR team took an
Icom repeater and stuffed the filters inside the box.
It worked good.
The project will need to fit into a small are and all
filters need to be self-contained.
Quiet fan cooling and food screens, etc. And you may
need to build 5 to 10 working units. One unit will
fly in to space the other 9 or so will be given to
each one of the training and testing departments in
The new radio I am proposing for voice, packet and
SSTV does not have dual receivers or cross band. We
just had too many issues with teaching the crew how to
use a true dual bander and it just is not worth going
through that mess again.
Keep it simple, One band active at a time.
73 Miles WF1F
--- Thomas McGrane <patrick.n2oeq at gmail.com> wrote:
> Hi miles- just a short response- I no longer wait to
> hear the astronauts
> calling CQ and realize the future operation will be
> vastly independant of
> the crew. Considering the almost exclusive use of
> simple digipeating packet
> for several years, I have been pushing for
> cross-band repeater operation to
> liven things up. Does the digital radio have
> crossband capability???
> Incidentally, the radio I mentioned can be used to
> monitor both VHF and UHF
> Whatever you do, please consider mostly unattended
> operation aside from use
> by the crew.
> I would rather be talking to fellow "space Cadets"
> on earth than waiting
> months for nothing.
> Thanks, pat
> On 6/4/07, MM <ka1rrw at yahoo.com> wrote:
> > Hello Patrick,
> > Thank you very much for your comments on the Marex
> > Project proposal. We are always interested in
> > pros and cons for all projects and welcome
> > constructive input.
> > We believe in the slogan Keep It Simple (KIS).
> > When it comes to projects we sometimes Dumb them
> > to make it easier for the ISS crew. Sure these
> > are very smart, but they do not have time to find
> > read the manuals for the 50+ radio, etc on ISS.
> > Examples:
> > On Mir Marex flew the Kenwood TM-D7A. This radio
> > used to run the SSTV project and became the
> > Voice link. This and other Kenwood's have a row
> > Program Mode buttons (I call them function
> > They allow you to save different modes of
> > and can be very complicated. After reading the
> > manuals several times and testing the PM buttons,
> > decided it would be too complicated for the crew
> > understand these buttons, so we disabled them.
> > Actually I programmed all of the PM buttons to do
> > the same two items, Go To Channel #1 and Set
> > Power to Low. That way if the crew hit a PM
> > they did not have to worry about rebooting the
> > into a different configuration.
> > Slow Scan TV:
> > On ISS, Silicon Pixels custom designed software
> > for ISS. We chose them because they had the best
> > solution at the time for SSTV. However, there off
> > shelf version of software "CPIX" wold have been
> > complicated for the crew to understand. There
> > many great features that the ISS crew just would
> > have time to learn. The Silicon Pixels team
> > a Dumbed down version of software that had just
> > basic features that the ISS crew would need. We
> > to make it as simple as possibly by deliberately
> > deleting features that were not needed. And we
> > the Buttons big so the crew could hit them easily
> > while floating in Zero-G.
> > For the new Dual band Radio proposal that Marex
> > put forward, I wanted to again try to Keep it
> > I wanted to avoid the problems associated with a
> > Dual-Band radio, such as two volume controls, two
> > squelches and a Band switch etc. The ISS crews
> > been having problems with figuring out a "Function
> > Button" radio verses a Channel knob radio. I
> > to go back to 1 channel knob, 1 squelch and 1
> > control.
> > The Icom ID-800 seems to meet most of our
> > for Keeping it Simple. Once we program the radio
> > the ground the ISS crew only needs to know the
> > following controls:
> > Power Switch
> > Channel Knob
> > Volume Knob
> > Squelch knob.
> > Instructions for changing frequencies, bands or
> > Modes will be as follows.
> > Turn Channel knob to channel XYZ.
> > Turning on Packet will be as simple as:
> > Turn Channel knob to channel XYZ.
> > Push power button on TNC and look for Green LED on
> > TNC.
> > Believe me, it's a lot simpler to use than what we
> > currently have in space.
> > Digital Voice Modes:
> > The ID-800 does support digital voce modes and all
> > normal Analogue FM modes. Since our goal is to
> > as many people as possible, the primary mode will
> > Analog FM voice. The digital modes wold most
> > be used for semi-private family communications,
> > Deliver Time Frame:
> > This project is not approved at this time. We
> > have approval to continue with the Kantronics
> > Modem side the project. Back in the Old Mir days,
> > longest it took me to Pitch a theory to Switch on
> > 15 months (SSTV Mir, Pitch theory September 1997,
> > Switch on December 1998). With ISS, it takes much
> > longer. I am tying to use a radio that will still
> > in production when we go into space.
> > The next project proposal demonstration is
> > planned for Moscow in Late 2007 or early 2008.
> > Thanks for your input and support.
> > Miles
> > www.marexmg.org
> > --- Patrick McGrane <N2OEQ at aceweb.com> wrote:
> > > Hi miles- de patrick n2oeq- nice to see you
> > > of the future. I miss the MIR
> > > days. I think there was a simple kenwood dual
> > > on the MIR. I looked at the icom
> > > ID800 and my first impression was that it was
> not a
> > > simple radio and I am not
> > > interested in buying a new digital radio to work
> > > ISS. Since there is no rush,
> > > please consider other radio models of SIMPLE
> > > Within the past couple of years I
> > > purchased a very easy to operate Yaesu FT8800R
> > > band rig capable of cross-band
> > > repeat, 9600 baud packet, and narrow FM
> operation to
> > > name a few. I looked at several
> > > rigs before deciding on it. Of course, it was a
> > > personal preference and others may
> > > prefer other models but I found this to be my
> > > for satellite work etc.
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