[amsat-bb] Re: The Whole GEO Package
vk3jed at gmail.com
Thu Dec 20 12:10:44 PST 2007
At 12:29 AM 12/21/2007, Bruce Robertson wrote:
>In this spirit, might I ask this list to imagine what needs to be done to
>make the emcomm/geo package a reality? The following is my rather long
>analysis of the situation.
Nice post Bruce, well thought out. :)
>However, I also think the EMCOMM branch of our hobby has different needs
>than the usual satellite station operator. If we are to really and honestly
>make the world a safer place and save lives, I think we will need to
>provide a GEO EMCOMM package that will require us as a organization to
>branch into some new and exciting efforts. Let me explain what I mean.
Well I for one am excited at the prospects of this venture. As
someone who participates regularly in international service nets
(thanks to VoIP and the Internet), the possibility of a satellite
based alternative path (i.e. redundancy) is of great interest to me,
especially as it will be independent of traditional telco infrastructure.
>Traditionally, a satellite station has been developed through one person's
>expertise gradually growing regarding a number of interrelated aspects: low
>signal VHF and UHF operation; the mechanics of an az-el antenna array;
>computer control; and doppler correction. Certain satellites or operating
>habits allow one to omit one or more of these, but in general it's, even by
>ham standards, a challenging array of new skills and understanding. I'd say
>the members of AMSAT are self-selected as those who enjoy this challenge
>and seek to learn as many aspects of the field as possible.
Agreed, and each satellite operator has different specialities. I'm
not one for the mechanics of AZ/EL rotators and the like, but I am
able to operate LEOs under difficult conditions.
>However, for an EMCOMM system to be effective, it cannot rely on a broad
>array of such specialized knowledge: it is unreasonable to expect that the
>first ham on the scene of a disaster will be one of the AMSAT 'us', a
>person who has acquired this specialized knowledge. It is only reasonable
>to assume that it will be an amateur radio operator, familiar with the
>general principles of radio theory and operation. In fact, in my region the
>EMCOMM specialists and the technical specialists (if I might put it that
>way) are often not the same people.
Also, a disaster area may require a blending of technologies. VoIP
has demonstrated this can be effective, and has shown some of the
techniques. This knowledge can be applied to satellite based links
(essentially replacing the Internet segment with a satellite
segment). In other words, the ground station package needs to be
versatile as well, and able to interoperate with other amateur
infrastructure such as VHF/UHF simplex and repeater networks.
>So our challenge is more extensive than the challenge that faced AMSAT with
>any previous launch: we need to make communication through this bird
>possible for any ham shmoe who is opening up a box of equipment after, say
>an afternoon of instruction half a year ago. Please note, this is not a
>matter of dumbing-down the bird or making it uninteresting. In fact, for
>the old-hands and the technically adept around here this will be very
>interesting and a great outlet for our skills. In this application, if not
>on all birds, we should take it as a sign of success when people
>effortlessly get connected, because it would mean that, in a true emergency
>there would be a greater likelihood of useful service.
I see it goes deeper than this, and we need to come up with a range
of solutions, such as the following (not an exhaustive list) of examples...
End user ground station.
Terrestrial repeater/VoIP to satellite link
Terrestial data to satellite data link (could be used for email to
the Internet, or eventually link amateur data networks to operators
in the field)
Terrestrial HF to satellite link
Each of these has different requirements, though at least the first
two should be able to communicate with each other (HF SSB is
notoriously difficult to link to anything, and may be best handled a
different way initially). The first two could be considered
analogous to an Echolink PC user and an Echolink or IRLP RF node in
our VoIP systems. The HF one was thrown in as an exercise in lateral
thinking, given that HF SSB to satellite based SSB may serve some
purpose in specialised situations. That could potentially
revolutionise nets such as the Travellers Net here in VK, which
provides a point of contact for stations travelling in remote areas
of the VK region.
>If this analysis is accurate, we need to imagine, broadly, three things: a)
>the services (or modes) this ham will offer to support EMCOMM; b) the box
>of stuff that this ham opens up; c) the afternoon's training she undertook
>to know how to use it. These are interrelated, of course. The training is
>apropos the box of stuff, and the box of stuff allows the services. They
>should also, I think, be *standardized* to an extent that has not been the
>case before with satellite work. Recently I heard the argument on Amateur
>Radio Newsline that ham EMCOMM services should be more interchangeable
>across the continent; the same will surely be the case regarding this work.
>Ideally the 'stuff' and the training is the same everywhere so that the
>shmoe has a chance of recollecting her training and is required to factor
>out/in as few local variables as possible.
Why limit one to a single continent, in the world I operate, that's
an excessively narrow limitation. We need _global_ standards,
especially if the Intelsat deal goes all the way and we have global
satellite coverage, and we need a package or packages that can
fulfill the varied roles outlined above.
>The advantage we have is that it isn't unreasonable to expect the box of
>stuff to be perhaps more pricey than individual hams would like such things
Agreed, these are most likely to be purchased by groups. However, we
still need some aspects of the P4 birds to be readily accessible to
individual hams without needing deep pockets. :)
>A large part of a) and b) will be determined by the ACP team, whose goal
>even with Eagle was to provide ground-station hardware alongside the bird's
>hardware. (The wisdom of this new approach should be applauded; I'm sure it
>has made re-purposing Eagle hardware for P4/EMCOMM much easier to imagine.)
>As I've argued before, I think one of the most important mode we can offer
>is simple Internet connectivity, allowing the emergency services folks to
>use the communication tools like email with which they are most familiar. I
Well, the importance of email is open to debate, and for some of us
opens a potential can of worms, but I certainly agree that some level
of data connectivity is needed. I see a particular technical
challenge here in that the data connectivity needs to be
versatile. Packet radio and Pactor are used heavily in these parts
for emergency and service nets, alongside voice. I'm not aware of
any traditional email use.
>Finally, the course. Can we provide standard lesson-plans, ppt slides and
>the like? I think this would significantly lower the bar on each of us
>teaching a session on P4 to our local club or EMCOMM group.
This would make sense.
>I think we should spread the load on these tasks as early as possible,
>making many of us participants in the final goal of increasing the safety
>of our communities and nations. I'm excited to hear what others think about
>the broader implications of the P4 initiative and how we can deliver on the
>whole GEO package.
This may open a whole new era. It also makes the package more
attractive to Intelsat as well, as they stand to gain a lot of good
publicity from supporting these goals. And if they gain more, then
it's more likely to go ahead and proceed to full implementation.
73 de VK3JED
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