It pleases me greatly to announce that Eric Ellison has been presented
with an award from AMSAT. It is sometimes easy to take for granted
what seems to many to be a small thing. In the case of AMSAT, Eric's
work made virtual meetings not only possible but easy. AMSAT has
literally run its Eagle project using VOIP facilities which Eric set up
on behalf of the technical groups active today in amateur radio in
satellites, technology, and in particular software defined radio. AMSAT
and …
[View More]TAPR both recognize Eric's work, AMSAT with the award and TAPR
membership with Eric's election to its board of directors. Someday
Eric's TEAMSPEAK server will be universally recognized for the
spectacular impact it has had and will continue to have.
Eric, the award is in the mail from the AMSAT office along with a gift
membership in AMSAT for a year.
Jim Sanford, Eagle project manager, and I and the entire organization
give you our thanks for your generosity and help.
73's
Bob McGwier
N4HY
--
AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL,
TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair
"You see, wire telegraph is a kind of a very, very long cat.
You pull his tail in New York and his head is meowing in Los
Angeles. Do you understand this? And radio operates exactly
the same way: you send signals here, they receive them there.
The only difference is that there is no cat." - Einstein
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I know all of the Eagle designers will join me in congratulating Marc
Franco, N2UO on his being granted permanent residency here in the U.S.
His skills represent a major asset to Eagle, Lintech, and the U.S. [in
that order ;-)] and it is good when the immigration office does
something sensible for a change.
CONGRATULATIONS Marc!
Bob
N4HY
--
AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL,
TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair
"You see, wire telegraph …
[View More]is a kind of a very, very long cat.
You pull his tail in New York and his head is meowing in Los
Angeles. Do you understand this? And radio operates exactly
the same way: you send signals here, they receive them there.
The only difference is that there is no cat." - Einstein
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Team:
I wish to announce that Bob Davis, KF4KSS, has assumed the role of
Structure and Mechanical Team Leader. Bob has experience in finishing
and integrating AO-40, and is employed in the aerospace industry, where
he has acquired significant experience since the AO-40 campaign.
Dick Jansson, WD4FAB, has led this team for several years and is not
going away. Dick will support Bob as a team member, focussing on
structural team coordination and thermal design and analysis.
Dick told me …
[View More]this afternoon, "I'm really excited to see the new blood
coming in and assuming leadership roles. I look forward to supporting
Bob and being on his team."
I thank Dick for all that he has done for AMSAT and WILL do for Eagle
and AMSAT. Thanks for all you've taught us.
Bob, thanks for stepping up to the plate. I look forward to working
with you, and I look forward to learning from you.
Thanks and very 73 to all,
Jim
wb4gcs(a)amsat.org
Eagle Project Manager
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I have asked the following folks to be AVP for Engineering.
Jim Sanford as Eagle project manager
Lou McFadin as Manned Space chief engineer
Bob Davis as lab director and spacecraft integration leader
Please add them to the officers mailing list if they are not already on
it please.
Welcome and thank all of them for their continued great service to AMSAT.
Bob
N4HY
--
AMSAT Director and VP Engineering. Member: ARRL, AMSAT-DL,
TAPR, Packrats, NJQRP, QRP ARCI, QCWA, FRC. ARRL SDR WG Chair
"…
[View More]You see, wire telegraph is a kind of a very, very long cat.
You pull his tail in New York and his head is meowing in Los
Angeles. Do you understand this? And radio operates exactly
the same way: you send signals here, they receive them there.
The only difference is that there is no cat." - Einstein
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Folks,
Coincidentally at the Symposium, Graham Shirville spent some time
coordinating proposed frequencies to some satellites, including Eagle, and
after a suggestion I had from from Drew KO4MA, I reiterated to Graham that
it may be advantageous to propose S1 frequencies right down at the bottom
1MHz of the 2.4GHz satellite allocation.
802.11 specifies a 1MHz guard band at 2400 to 2401MHz for regulatory OOB
emission reasons. Signals +/-11MHz from the centre must be at least 30dB
down from the …
[View More]carrier. Channel 1 is at 2412MHz.
Taking into account Doppler, the recommended S1 coordinated frequencies will
be at the bootom end of 2400MHz without the possibility of OOB emissions on
Earth due to Doppler.
73, Howard G6LVB
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Team:
A few days ago, I made a proposal for naming Eagle's communications
services and solicited comments. I received many good comments.
I really think it important that we have unambiguous service class
names. Based on all the comments, I propose:
U/V "linear"
L/S "linear"
Text messaging
Low Rate ACP
High Rate ACP
While I'd prever something less ambiguous than "linear", our customers
seem to understand that "linear" means SSB/CW/PSK31/SSTv . . . . etx.
Any strong …
[View More]objections to this?
If not, I'll get the announcement on AMSAT.org changed. It's time to
get precise.
Thanks & 73,
Jim
wb4gcs(a)amsat.org
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Last evening I tried to convey the concept that the critical-command
modules needed to be of low-power design to insure their operability
during the occasional rather lengthy eclipse cooling of the spacecraft.
My message apparently did not sink in. John reports that his design of
such a U band receiver would be dissipating some 3.5W due to its
bullet-proof nature against 3rd-order IM products needed for protection
on the U band.
If we go forward with such a module of that nature, it will need …
[View More]to have
thermal control tapes on it to provide a mean emittance of about e=0.45.
In a 3 hour eclipse we can expect to see spaceframe temperatures down to
-100°C (173K) or lower. With such an environment John's module would be
expected to see temperatures down to at least -44°C, which is a bit
frosty for electronics that are expected to provide the critical
services of commanding the spacecraft. Such operating temperatures are
not felt to be advisable for that service.
If John's module were of the 1W category, temperatures of the receiver
could be expected to be in the range of -15°C to -20°C which would be
more operable for the service.
The above numbers are, of course, based on estimates which will be
confirmed after we have the new spaceframe fully designed and analyzed.
The "warmer" temperatures of the lower power modules are those that have
been experienced and measured by telemetry from AO-10 and AO-13. These
projections are thus based on 25 years of experience in these design
concepts.
Dick Jansson
---------------------------
<mailto:rjansson@cfl.rr.com> rjansson(a)cfl.rr.com
---------------------------
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The ARRL Letter, Vol. 25, No. 41 released on October 13, 2006 mentions
Eagle. Here is a copy of the Eagle item for those who don't get this via
ARRL channels ...
--
73 de JoAnne K9JKM
k9jkm(a)amsat.org
==>AMSAT'S PROJECT EAGLE SATELLITE SHIFTS DIRECTION
AMSAT-NA has announced it's revamping the design of its high-Earth orbit
(HEO) Project Eagle satellite, currently in the development stages
<http://www.amsat.org/amsat-new/eagle/>. The next generation satellite will
take maximum …
[View More]advantage of software-defined transponder (SDX) technology to
offer a broader range of easily accessible Amateur Radio payloads. The AMSAT
Board of Directors okayed the Eagle upgrade plans during the 2006 AMSAT-NA
Space Symposium and Annual Meeting held October 6-8 in San Francisco. Eagle
Project Manager Jim Sanford, WB4GCS, outlined the changes at his Space
Symposium forum October 7.
"The structure which we have been presenting for several years is not going
to meet our mission needs," Sanford explained. "We have moved on to a later
structure."
Under the new plan, Sanford says, Eagle's communications payloads will
include a mode U/V linear transponder for SSB, CW and other modes. A second
SSB/CW transponder will uplink on L band (1.2 GHz) and downlink on S1 band
(2.4 GHz). Both would be usable over 75 percent of the satellite's orbit by
an AO-13 or AO-40-capable ground station, AMSAT says.
Something new to Amateur Radio satellites is a planned low-rate text
messaging system similar to cellular telephone SMS. Sanford said the
text-messaging capability may prove valuable for providing emergency and
disaster communication. It will operate in mode U/V and also will be
available to modest ground stations over 75 percent of Eagle's orbit.
Eagle will also carry an advanced communications payload (ACP). The ACP will
accommodate voice communication using an S2 band (3.4 GHz) uplink and a C
band (5.8 GHz) downlink via a single 60 cm dish on the ground. As an
alternative -- for stations in those parts of the world where 3.4 GHz is
unavailable -- Eagle will provide an additional L band uplink.
The ACP also will offer high data rate communication including the
possibility of full-motion compressed video in S2/C mode. The same mode also
could support an Internet link. Ground-station antennas for Eagle may even
pass muster in neighborhoods governed by private deed covenants, conditions
and restrictions (CC&Rs), Sanford suggested.
During a presentation on the ACP, Matt Ettus, N2MJI, said one of the goals
of the package is to open up the satellite to a new base of users, not just
restrict it to elite satellite operators and sophisticated ground stations.
Embracing SDR technology simplifies signal handling, he explained, because
going digital is just a matter of transmitting bits up and down.
"The satellite doesn't really care what the bits mean," he said. The
satellite "just reflects bits," and most policy-type issues will be handled
by ground stations.
The satellite's signal will present one wideband downlink containing
multiplexed data. "There will be room for many, many carriers in the
passband," Ettus predicted. The mix of users would be apportioned among both
low and high-rate modes, depending on overall traffic.
Plans call for electronically steering the satellite's antennas to mitigate
the effects of the spacecraft's spin and maximize the spacecraft's
accessibility. In a subsequent forum, AMSAT board member and well-known
satellite expert Tom Clark, K3IO (ex-W3IWI) discussed some of the
mathematics and physics that would permit steering a 37-element S band
antenna array on Eagle.
"We would intentionally steer that pattern, so the array is always pointing
toward Earth," Clark said, regardless of spin factor. He described a system
of interferometers to do the pointing on the basis of "master beacon
signals" uplinked from different points on Earth's surface. "It [Eagle] will
measure where they are and know where to point the beam," he explained.
In a presentation on applying SDR techniques to satellite transponders,
Howard Long, G6LVB, described and demonstrated a prototype SDX board. "This
is the holy grail of what we've been trying to do," he told his audience.
Long showed how his hand-soldered SDX could be configured to accommodate
various signal strengths and types within the same passband and even to
easily notch interfering signals quickly and flawlessly.
Sanford concluded his presentation by saying it's time to take the AMSAT
board's concrete decisions and plan, schedule and build Eagle. "We're about
to start spending some serous money," he said. During a later
question-and-answer session, Sanford stressed that reliability of the
ultimate Eagle satellite is a key goal. "I want no single-failure mission
kills on this satellite," he said.
Project Eagle still needs to raise $33,500 by December. Eagle could launch
by 2010. The whole project will cost some $600,000.
During the AMSAT-NA annual meeting October 8, President Rick Hambly, W2GPS,
expressed his enthusiasm for Project Eagle. "I think it will be the greatest
thing we've ever done!" he said. The 2007 AMSAT Symposium and Annual Meeting
will take place in Pittsburgh.
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Bill Pasternak, WA6ITF sends out a pre-release copy of the Amateur Radio
Newsline broadcast script to the ANS editors. This week's Newsline will
include news about Eagle. Here's a copy for anyone interested ...
--
73 de JoAnne K9JKM
k9jkm(a)amsat.org
HAM RADIO IN SPACE: THE EAGLE WILL FLY
AMSAT's Board of Directors has approved the payloads for the upcoming Eagle
ham radio satellite. Bill Pasternak, WA6ITF reports:
--
Of primary concern to most radio amateurs world-wide was the …
[View More]decision to
include an SSB and C-W transponder transponder with uplink on 70 centimeters
and a downlink on 2 meters. What AMSAT calls U-Band and V-Band. This means
that Eagle will be usable over 75% of an orbital pass by any AO-13 or AO-40
capable ground station. In other words, Eagle will be backward compatible
with most previous ham radio satellites.
Other transponders include SSB and C-W with an uplink on L-band and a
downlink the 2.4 GHz S1-band and a low rate text message system operating on
the UHF and VHF bands. These transponders will be implemented using
Software Defined Radio technology.
But thats not all.. AMSAT says that Eagle will also carry an advanced
communications payload or A-C-P. The A-C-P will allow voice communications
uplinking on the S2-band at 3.4 Ghz and downlinking on C-band at 5.8 Ghz.
It will do all of this using a single 60cm dish. The satellite antennas
will be electrically steered to reduce spin modulation and allow use over
75% of any given orbit.
An additional, fix-pointed, uplink will be available at L-band. This L-band
uplink will require a separate antenna at the ground station. Also on-board
will be C-band equipment for high rate data communications such as streaming
video.
For the Amateur Radio Newsline, Bill Pasternak, WA6ITF, in Los Angeles.
--
The AMSAT board announced its selection following a meeting on October 5th
in Sam Francisco. It also said that AMSAT will develop and make available
an affordable ground segment for the ACP system. Additional information
will be posted at www.amsat.org in the near future. (AMSAT)
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