[ans] ANS-028

Dee morsesat at optonline.net
Sat Jan 27 21:44:40 PST 2007


 

AMSAT NEWS SERVICE
ANS-028

ANS is a free, weekly, news and information service of AMSAT North America, 
The Radio Amateur Satellite Corporation. ANS reports on the activities of a 
worldwide group of Amateur Radio operators who share an active interest in 
designing, building, launching and communicating through analog and digital 
Amateur Radio satellites.

Please send any amateur satellite news or reports to:

ans-editor at amsat.org

In this edition:

* End of PCSAT-1 Full Sun Digipeater Operations
* OSCAR 11 Request for Reports
* OSCAR 7 News
* ARISS Status - January 2007
* Satellite Shorts From All Over
* Energizing Young Minds 


SB SAT @ AMSAT $ANS-028.01
End of PCSAT-1 Full Sun Digipeater Operations

AMSAT News Service Bulletin 028.01
 From AMSAT HQ SILVER SPRING, MD.
January 28, 2007
To All RADIO AMATEURS
BID: $ANS-028.01



Bob Bruninga, WB4APR, writing from the US Naval Academy Satellite
Lab in Annapolis, Maryland reports, "We've reached the end of 
PCSAT-1 packet digipeater operations from the most rececnt full
sun period."

During the 1/19/07 afternoon pass over USA, PCSAT-1 was overloaded 
over the west coast and crashed back to W3ADO-1 at 1850z.  But one
minute later ground controllers had AOS at the Naval Academy ground 
station and recovered it to PCSAT-1 and digipeating.  

But the number of users was just so high, that there was no way
PCSAT-1's batteries would survive the next eclipse.  So after 8 
minutes of operations and just prior to LOS, the Naval Academy 
turned off the digipeater and set the MYCALL to NODIGI as a way of 
letting users know the digipeater was off.

This is probably the end of this PCSAT-1 operating period.  Ground
controllers will see if the NODIGI will hold.  But eclipses still 
get longer and eventually PCSAT-1 will be back to resetting on every 
orbit and be practially useless except mid-day sunnyside passes for 
a lucky packet or two.

The next full receovery period will be the second week in March.

[ANS thanks Bob Bruninga, WB4APR at the US Naval Academy Satellite 
 Ground Station for the above information]

/EX 


SB SAT @ AMSAT $ANS-028.02
OSCAR 11 Request for Reports

AMSAT News Service Bulletin 028.02
 From AMSAT HQ SILVER SPRING, MD.
January 28, 2007
To All RADIO AMATEURS
BID: $BID:U2RPT129.CWV


    
TELEMETRY AND REPORTS WANTED!

To investigate the date problem mentioned below, I would welcome some
telemetry from differents parts of the world, at times when the orbits do
not pass over the UK. These times are approximately from 10:00 to 16:00 and
from 19:00 to 04:00 UTC. If you don't have a decoder, I can now accept
short WAV files of good audio, duration up to 30 seconds.

I would also like reports of reception around the times of expected beacon
switch ON and OFF. No telemetry wanted, just when you listen, and whether
you heard, or didn't hear the bird. Please e-mail to the address below.

During the period 29 December 2006 to 23 January 2007, the satellite was
heard from 08 to 18 January. Good steady signals have beeen heard on all
passes, and excellent copy of the telemetry obtained.

The on-board clock has maintained accurate time, over the reporting period,
gaining 2.5 seconds. However the hour counter sometimes shows an error of
of 10 hours, ie. in its most significent digit. The 'day of the week'
counter operates reliably, zero representing Thursday.

The date counter appears to be incrementing correctly, but the day of the
month is not reset to one, at the end of each month.  Possibly, it resets
to 41, ie. the unused bit representing 40 permanently stuck at a one. On 17
January the date was shown as 51 December 2006.  Further investigation is
required to establish exactly how the date connter changes.

If the satellite's watchdog timer continues to operate normally, the beacon
should switch ON around 28/29 January 2007. The satellite is in full sunlight
at the present time, and will remain in this state until mid-April 2007,
when eclipses start again.

I am indebted to Bob G4VRC and Dean AL7CR for their reports. Reports around
the times of the expected beacon switch ON/OFF, are especially useful. Many
thanks.

The current status of the satellite, is that all the analogue telemetry
channels, 0 to 59 are zero, ie they have failed. The status channels 60 to
67 were still working. The spacecraft computer and active attitude control
system have switched OFF, ie. the satellite' attitude is controlled only by
the passive gravity boom gradient, and the satellite is free to spin at any
speed. When telemetry was last received it showed that one of the solar
arrays had failed, and there was a large unexplained current drain on the
main 14 volt bus. After 22 years in orbit the battery has undergone around
100,000 partial charge/discharge cycles, and observations suggest that it
cannot power the satellite during eclipses, or sometimes during periods of
poor solar attitude.

The watchdog timer now operates on a 20 day cycle. The ON/OFF times have
tended to be very consistent. The average of many observations show this to
be 20.7 days, ie. 10.3 days ON followed by 10.4 days OFF. However, poor
solar attitude may result may result in a low 14 volt line supply, which
may cause the beacon to switch OFF prematurely, and reset the watchdog
timer cycle. When this occurs, the beacon is OFF for 20.7 days.

The Beacon frequencies are -

VHF 145.826 MHz.  AFSK FM  ASCII Telemetry

UHF 435.025 MHz.  OFF

S-band 2401.5 MHz. OFF

Listeners to OSCAR-11 may be interested in visiting my website. If you need
to know what OSCAR-11 should sound like, there is a short audio clip for
you to hear. The website contains an archive of news & telemetry data. It
also contains details about using a soundcard or hardware demodulators for
data capture.  There is software for capturing data, and decoding ASCII
telemetry.  The URL is www.users.zetnet.co.uk/clivew/


[ANS thanks Clive, G3CWV, for the above information]

/EX

SB SAT @ AMSAT $ANS-028.03
OSCAR 7 News

AMSAT News Service Bulletin 028.03
 From AMSAT HQ SILVER SPRING, MD.
January 28, 2007
To All RADIO AMATEURS
BID: $ANS-028.03




Yesterday afternoon I had the distinct pleasure of working some DX on AO-7 
mode B from here in subtropical Florida. I caught a 4 degree max pass to the 
northeast that eventually covered a good bit of northwestern Europe, and had 
the pleasure to catch G1WPR in IO93 finishing up with K3SZH. Signals were 55 
with some QSB on my uplink, probably due to all the energy wasted in heating 
the neighborhood palm trees. My QTH does not have what anyone could consider 
a clear horizon! As I was going LOS I also heard I believe W3JZ working 
G1WPR. At the time the footprint extended across the US from Idaho to 
Central Florida, and just about all of Canada, so the opportunity to work 
some satellite DX is there for many.

The 24 hour timer continues to change modes while the satellite is in 
continuous illumination, with the mode change occurring around 1130 UTC. 
Eclipses return April 3rd, 2007, and we expect the timer to be interrupted 
near this date.A good website to check to quickly find out what mode it is 
in can be found at: http://oscar.dcarr.org/ .

Good Luck and enjoy!

[ANS thanks Drew, KO4MA,for the above information]

/EX


SB SAT @ AMSAT $ANS-028.04
ARISS Status - 26 January 2007

AMSAT News Service Bulletin 028.04
 From AMSAT HQ SILVER SPRING, MD.
January 28, 2007
To All RADIO AMATEURS
BID: $ANS-028.04




INTERNATIONAL SPACE STATION STATUS REPORT: SS07-04

 HOUSTON - This week, the crew aboard the International Space Station 
 prepared for an unprecedented series of spacewalks. NASA astronauts 
 Mike Lopez-Alegria and Suni Williams are scheduled to begin a 
 6.5-hour spacewalk from the station around 9 a.m. CST on Wednesday, 
 Jan. 31. It will be the first of a record four spacewalks planned 
 during the next month. 

 Lopez-Alegria and Williams will conduct other spacewalks on Feb. 4, 8 
 and 22. The first three spacewalks will originate from the station's 
 Quest airlock and the astronauts will use U.S. spacesuits. 
 Lopez-Alegria and cosmonaut Mikhail Tyurin will use Russian 
 spacesuits for the last spacewalk and will exit the station from the 
 Pirs airlock. 

 The three U.S. spacewalks will rearrange the station's cooling system, 
 bringing online new portions of the system that were activated during 
 a shuttle mission in December 2006. The Russian spacewalk will free a 
 stuck antenna on the ISS Progress 23 cargo craft docked to the aft 
 end of the station, ensuring that craft can safely undock in April. 

 The crew began the week unloading some of the more than 2.5 tons of 
 food, fuel and supplies that were delivered to the station on Jan. 19 
 by the ISS Progress 24 cargo craft, which included fresh produce, 
 gifts from home, new clothing, spare parts, oxygen and water. 

 The crew's attention quickly turned to preparations for the upcoming 
 spacewalks. On Monday, the crew began working with the U.S. 
 spacesuits. Batteries for the suits were charged, and the suit 
 cooling systems were cleaned. 

 On Tuesday, Lopez-Alegria and Williams trained using an onboard, 
 laptop computer-based simulation. The training refreshed their skills 
 operating the Simplified Aid for Extravehicular Activity Rescue, or 
 SAFER, jetpack that is worn on spacesuits. The backpack allows 
 spacewalkers to fly back to the station in the event they become 
 separated from the complex. 

 On Thursday, ground controllers in Houston commanded the station's 
 robotic arm to maneuver into the position it will occupy for the 
 start of the spacewalk. Aboard the station, the crew reviewed the 
 plans for the first spacewalk. 

 Lopez-Alegria and Williams continued checks of their spacesuits and 
 checks of the SAFER backpacks Friday. The SAFER backpacks are 
 propelled by compressed nitrogen gas, and, during the checkout, the 
 harmless gas was released, depleting the nitrogen in one unit below 
 the usable quantity. Two other usable SAFER backpacks remain onboard, 
 however, and the loss of the third unit does not affect plans for the 
 upcoming spacewalks. 

 The crew took time during their work on Monday to speak with 
 television host Martha Stewart. Crew members also took time to field 
 questions by amateur radio from two schools, one in Ottawa, Ontario, 
 Canada, and another in Winnebago, Neb. 

 For more about the crew's activities and station sighting 
 opportunities, visit: 

 http://www.nasa.gov/station 

[ANS thanks Arthur, for the above information]

/EX



SB SAT @ AMSAT $ANS-028.05
Satellite Shorts From All Over

AMSAT News Service Bulletin 028.05
>From AMSAT HQ SILVER SPRING, MD.
January 28, 2007
To All RADIO AMATEURS
BID: $ANS-028.05

* Ed Long, WA4SWJ, the Editor of The AMSAT Journal is asking for help
translating a technical article written in German into English.  Ed
wrote, "I have a highly interesting technical article for the Journal 
on oscillator stability but it is written in German. Unfortunately I 
cannot make the translation and need some help. Is anyone out there 
able to translate German that could help? John Bubbers used to do that 
for us but he has retired so I need some assistance. It is several 
pages long. You'll get credit in the Journal for the translation."

* The Tokyo Institute of Technology Cute-1.7+APD team reported this 
week that the call sign of C0-56 (also known as Cute-1.7 + APD) had to 
be changed from JQ1YCC (old call sign) to JQ1YPC (new call sign).
See:  http://lss.mes.titech.ac.jp/ssp/cute1.7/index_e.html

* AMSAT-NA server manager Paul, KB5MU reported an outage with all 
callsign at amsat.org mail aliases (including anything at amsat.org addresses) 
between 0930z to 1852z on 1/24/07.  Service has been restored and no 
updates were lost. Messages sent to your mail aliases during the outage 
will have been bounced back to the sender with a "User unknown" error 
message. You may see some residual error messages still working their
way through the worldwide email system, but service at amsat.org should 
be back to normal now. If you see any ongoing problems with the mail 
alias system, please notify mail-alias-service at amsat.org and Paul 
promises to investigate.

* Pehuensat's elusive signal was copied in Buenos Aires, Argentina 
on 01/21/07 at 21:48 LU (GMT-3). Pehuensat-1 was heard on 145.825 with 
a weak but clear signal just above noise by ear, but they unable to 
decode the AX25 packet beacon. The rig was a FT-736 & omni super turn-
stile antenna for 2 meters. Engineer Jorge  Lassig, director of the 
Penhuesat Uncoma project informed amateurs that the satellite takes 
between 48 and 72 hours to charge its batteries, due to the inadequate 
position of the nosecone to which it is still attached in reference to 
the sun.  Once the batteries are recovered, the satellite transmits 
during several orbits until they discharge again causing the onboard 
computer to set the system in safe mode, leaving just the oscillator 
on.  Folks at Uncoma are evaluating when the nosecone will change its 
position in space to improve the battery charging process of Penhuesat.

[ANS thanks everyone for the above information]

/EX


SB SAT @ AMSAT $ANS-028.06
Energizing Young Minds

AMSAT News Service Bulletin 028.06
>From AMSAT HQ SILVER SPRING, MD.
January 28, 2007
To All RADIO AMATEURS
BID: $ANS-028.06




NEWINGTON, CT, Jan 24, 2006 -- Eleven electrical engineering students at 
The College of New Jersey
<http://www.tcnj.edu/%7Eengsci/> had a hand in designing some of the 
software defined radio (SDR)
hardware that will fly aboard SuitSat-2. The college seniors signed up 
last fall for "Software Defined Radio
," taught by adjunct professors Bob McGwier, N4HY, and Frank Brickle, 
AB2KT -- both members of the
Amateur Radio on the International Space Station (ARISS 
<http://www.rac.ca/ariss>) SuitSat-2 team.

The second SuitSat will have a software designed Amateur Radio 
transponder (SDX) on board. SuitSat-2
is being viewed as a test bed for the hardware AMSAT hopes to launch on 
its Phase 3E Eagle
<http://www.amsat.org/amsat-new/eagle/EaglePedia/index.php/Main_Page> 
satellite.

Early on, the students studied signal processing and communication 
theory as well as what Brickle
calls "esoteric corners of computer science." Then, using Matlab 
<http://www.mathworks.com/>
 -- a high-level technical computing language -- the students 
implemented modulators and
demodulators for SSB, FM, BPSK and AFSK.

"Students get a little bit of verbal swimming instruction, and then we 
toss them straight into the
ocean," is how Brickle described the process.

By mid-semester, the students were designing their experiments and 
getting them up and running.
Boards were powered up without diagnostic hardware or software, since 
that's how the circuitry
will be on orbit -- "walking a tightrope without a net," as Brickle sees it.

"Given the complexity of what the SDR/SDX in SuitSat-2 will be required 
to provide, the applications
 will need to run in an unprecedented software environment: pre-emptive 
multitasking under
freeRTOS," he explained. FreeRTOS is an open-source, round-robin 
operating system for
embedded devices.

Instead of being scared off, the students ran with the challenge and 
demonstrated obvious enthusiasm,
Brickle reports. "We will be doing a very good thing if we continue to 
involve these kids, and more like
them, in our future AMSAT projects," he said. What surprised him most, 
he added, was that the students
focused on taking new approaches to "very fundamental engineering issues 
that aren't flashy or trendy."
McGwier remarked that both students and teachers shared in the excitement.

The SuitSat-2 team, under the leadership of Lou McFadin, W5DID, has been 
working on the design of
a power converter for the solar panels, the internal housekeeping unit, 
the antenna mount, the transmitting
and receiving hardware and how it will mount atop the suit's helmet. An 
ISS crew could launch SuitSat-2
during a spacewalk as early as next fall. SuitSat-2 could have an 
operational lifetime of six months or more.

{ANS Thanks ARRL for this article}

/EX

In addition to regular membership, AMSAT offers membership in the President's 
Club. Members of the President's Club, as sustaining donors to AMSAT Project 
Funds, will be eligible to receive additional benefits. Application forms are 
available from the AMSAT Office.

73, 
This week's ANS Editor,
Dee Interdonato, NB2F
nb2f at amsat dot org






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