[amsat-bb] ANS-199 AMSAT News Service Special Bulletin - AMSAT Fox-1C Launch Opportunity Announced

Phil Karn karn at ka9q.net
Sat Jul 19 20:24:43 UTC 2014

On 07/19/2014 12:28 PM, Paul Stoetzer wrote:
> Are FM repeater satellites what we all want in orbit? No. Personally,
> I'd like a Mode J linear transponder in a sun synchronous circular
> orbit of about 2,000km (if we can't get anything to HEO).

Getting a launch opportunity is difficult and expensive. Going digital
is not.

> However, the Fox-1A, Fox-1B, Fox-1C, and Fox-1D satellites will
> eventually lead to the Fox-2 series of satellites.

I've been hearing that for years, so please forgive my skepticism. Tony
AA2TX himself told me that the analog Fox-1 would be followed by the
digital Fox-2. Now we have Fox-1B, Fox-1C, etc, that will also be
analog. Forgive me if I feel a little like Achilles racing the tortoise.

I originally joined AMSAT as a technical volunteer in mid 1980, shortly
after the Phase III-A launch failure. At the time, AMSAT was doing some
very impressive things. Many weren't even being done (or were just
starting to be done) in the commercial world: the use of digital command
and telemetry links, the use of onboard computers, even the use of
ground computers to steer antennas. AMSAT had shown how to locate an
emergency beacon by measuring its Doppler shift through a LEO
transponder -- which eventually became the SARSAT (Search and Rescue
Satellite) payload on many US and Russian LEO weather satellites.

And AMSAT was showing how to do it all on a low budget, with
resourcefulness replacing brute force bucks. I was blown away by clever
little tricks like spinning a satellite by painting one side of its
antennas black and the other side white. This was ham radio at its best.

But that was 1980. It's now 34 years later and we're still doing the
same old thing. Meanwhile, mobile phones and the Internet have gone from
the exotic to the commonplace -- and I don't have to tell you that
they're 100% digital. TV broadcasting is also now digital, few cable TV
systems still carry analog signals, and FM and shortwave broadcasting
are in a digital transition.

When AMSAT showed how to use an inexpensive hand-held radio to
communicate with a satellite, no one had ever seen such a thing. Now
digital satellite broadcasting and GPS are nearly universal in cars,
hikers and boaters carry SPOT units, and you can buy handheld Iridium
phones that will work anywhere on the globe. All digital, of course.

Yet AMSAT continues to fly one analog satellite after another. Why?

All these outside developments have rendered FCC Part 97.1, the Basis
and Purpose of the Amateur Service, almost completely obsolete with the
singular exception of personal technical education and possibly (some)
emergency communications. You want to further international goodwill by
talking to people in other countries? Get on the Internet. You want to
call your wife to see if she needs anything? Pick up your mobile phone.
Further the technical art? Go work for a communications R&D company,
because it isn't happening in ham radio anymore.

How are we justifying our spectrum by doing the same thing over and over
again, while the world passes us by?

Appealing to "what the members want" doesn't fly with me, because "the
members" are a tiny fraction of our potential audience. AMSAT keeps
wondering why it can't seem to grow beyond a tiny niche; it need look no
further for the reason.

Nor does an appeal to "simplicity" and "cost" carry any weight. Mobile
phones, GPS units and Sirius/XM receivers may not be "simple" but that
doesn't keep them from being cheap and easy to use. It's their very
"complexity" (if you consider "digital" to be complex -- which I don't)
that makes them cheap and easy to use.

But by design they are impossible to take apart and learn from. That's
where the amateur service can still play a big role. For those who want
to learn communications technology by hands-on experimentation there is
still simply nothing like it. But where are the amateur digital voice
satellite systems to take apart and study? At least a linear transponder
could repeat an efficient digital signal, but with the trend to FM even
that is no longer possible. If an amateur satellite carries any digital
links at all, they are slow and generally limited to telemetry and
command, not user-to-user communications. Many don't even use modern
modulation and error-correction methods, making them that much harder to
access with the small antennas to which most hams are now limited
because of CC&Rs and other restrictions.

Far from being "elitist" or "hard to use", digital represents the *only*
way forward. It's time to move into the 21st century.


More information about the AMSAT-BB mailing list