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CX2SA > SATDIG 10.08.13 21:00l 401 Lines 15748 Bytes #999 (0) @ WW
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Subj: AMSAT-BB-digest V8 260
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Sent: 130810/1902Z @:CX2SA.SAL.URY.SA #:9555 [Salto] FBB7.00e $:AMSATBB8260
From: CX2SA@CX2SA.SAL.URY.SA
To : SATDIG@WW
Today's Topics:
1. Re: HF Amsat net (JoAnne Maenpaa)
2. Astronaut Mike Foale KB5UAC Leaves NASA (Clint Bradford)
3. AMSAT Awards (Bruce)
4. Re: AMSAT Awards (Bryce Salmi)
5. Re: Non-mechanical feedback follow up (Robert Bruninga)
6. Re: Rotator Positioning questions (Greg D)
7. Cubesat 2013 Summer Workshop live video stream (Samudra Haque)
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Message: 1
Date: Fri, 9 Aug 2013 14:07:41 -0500
From: "JoAnne Maenpaa" <k9jkm@xxxxxxx.xxx>
To: <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: HF Amsat net
Message-ID: <007e01ce9533$b95b6b50$2c1241f0$@xxx>
Content-Type: text/plain; charset="us-ascii"
> Is there still a net on 20 meters for AMSAT and what would the
> time, day and freq.?
AMSAT 20 meter international net meets on Sunday at 1900 UTC on 14282
KHz +/- for QRM. Net controls are W5IU and W7LB. The pre-net "warm up"
begins on the same frequency generally around 1800 UTC. This includes
general conversation, question/answer, etc.
The Houston AMSAT net meets Tuesday at 8PM Central Time (UTC-5 in the
summer). It is a 2M net simulcast on the AMSAT node on Echolink.
--
73 de JoAnne K9JKM
k9jkm@xxxxx.xxx
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Message: 2
Date: Fri, 9 Aug 2013 13:52:47 -0700
From: Clint Bradford <clintbrad4d@xxxxxxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Astronaut Mike Foale KB5UAC Leaves NASA
Message-ID: <FEA81DFB-B343-4A7E-AF5B-31B638CDBF96@xxxxxxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
Astronaut Michael Foale Leaves NASA After 26-year Career
NASA astronaut Michael Foale has retired, ending a 26-year space agency
career that included 375 days in space during six space shuttle missions and
extended stays aboard two space stations.
Foale spent 145 days aboard the Russian space station Mir in 1997 and 194
days aboard the International Space Station as commander of Expedition 8
from October 2003 to April 2004. He also conducted four spacewalks over his
NASA career totaling almost 23 hours.
"We salute Mike and his contributions to NASA as an accomplished member of
the astronaut corps," said NASA Administrator Charles Bolden. "Starting with
his first flight, shuttle mission STS-45, when we flew together in 1992,
Mike has worked tirelessly to support NASA's quest to explore the unknown. I
know Mike will go on to do more great things as he continues to support the
aerospace industry in his new endeavor."
Foale held many positions during his NASA career, including chief of the
Astronaut Office Expedition Corps, assistant director (technical) of the
agency's Johnson Space Center in Houston, and deputy associate administrator
for exploration operations at NASA Headquarters in Washington. He most
recently worked in support of Soyuz and International Space Station
operations, as well as space station spacewalk activity and spacesuit
development.
Foale's future plans include advancing green aviation technology. For
Foale's complete NASA biography, visit:
http://go.nasa.gov/14gPLKx
For more information about NASA programs, visit:
http://www.nasa.gov
-end-
------------------------------
Message: 3
Date: Fri, 09 Aug 2013 23:10:32 -0500
From: Bruce <kk5do@xxxx.xxx>
To: "amsat-bb@xxxxx.xxxx <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] AMSAT Awards
Message-ID: <5205BD38.9050302@xxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
As the AMSAT server is being rebuilt, I have just rebuilt all the AMSAT
award pages. You can reach them by going to amsat.org and clicking on
Services. You will find Awards under the drop down. At the bottom of the
main page is a link to all the award recipients. This information will
be the same information that appears on my website. I will keep them
both up to date.
73...bruce
--
Bruce Paige, KK5DO
AMSAT Director Contests and Awards
ARRL Awards Manager (WAS, 5BWAS, VUCC), VE
Houston AMSAT Net - Wed 0100z on Echolink - Conference *AMSAT*
Also live streaming MP3 at http://www.amsatnet.com
Podcast at http://www.amsatnet.com/podcast.xml or iTunes
Latest satellite news on the ARRL Audio News
http://www.arrl.org
AMSAT on Twitter http://www.twitter.com/amsat
------------------------------
Message: 4
Date: Fri, 9 Aug 2013 21:32:56 -0700
From: Bryce Salmi <bstguitarist@xxxxx.xxx>
To: kk5do@xxxx.xxx
Cc: "amsat-bb@xxxxx.xxxx <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: AMSAT Awards
Message-ID:
<CAN5j0sqVg82dBrryz0bdOyXdfP8L3Ntqou67z-hoJjdrcqJb6w@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
Awesome!
Thanks for your help and efforts on the awards section.
Bryce
KB1LQC
On Fri, Aug 9, 2013 at 9:10 PM, Bruce <kk5do@xxxx.xxx> wrote:
> As the AMSAT server is being rebuilt, I have just rebuilt all the AMSAT
> award pages. You can reach them by going to amsat.org and clicking on
> Services. You will find Awards under the drop down. At the bottom of the
> main page is a link to all the award recipients. This information will be
> the same information that appears on my website. I will keep them both up
> to date.
>
> 73...bruce
>
> --
>
> Bruce Paige, KK5DO
> AMSAT Director Contests and Awards
> ARRL Awards Manager (WAS, 5BWAS, VUCC), VE
> Houston AMSAT Net - Wed 0100z on Echolink - Conference *AMSAT*
> Also live streaming MP3 at http://www.amsatnet.com
> Podcast at
http://www.amsatnet.com/**podcast.xml<http://www.amsatnet.com/podcast.xml>or
iTunes
> Latest satellite news on the ARRL Audio News
> http://www.arrl.org
>
> AMSAT on Twitter http://www.twitter.com/amsat
>
> ______________________________**_________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings:
http://amsat.org/mailman/**listinfo/amsat-bb<http://amsat.org/mailman/listinfo
/amsat-bb>
>
------------------------------
Message: 5
Date: Sat, 10 Aug 2013 01:54:56 -0400
From: Robert Bruninga <bruninga@xxxx.xxx>
To: Zach Leffke <zleffke@xx.xxx>
Cc: AMSAT BB <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: Non-mechanical feedback follow up
Message-ID:
<CALdCfN+2XtK1sRUe5Dz71k-do5nzueW63N191vykN05rVS+yCQ@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
Just to clarify, the "time tracking" works just as well for the
elevation rotor. You can see my balloon chasing 2.4 GHz antenna on my
van here: http://aprs.org/balloons.html about 1/3rd down the page
(the second balloon mission). But it used a full Yaesu AZ/EL system
so I did have feedback.
My controller had two serial inputs, one was for the GPS in the van
and the other was to a TNC to receive the APRS posits from the
balloon. THen the controler does the math so the antenna remains
pointed at the balloon (or UAV or what have you)... (though you
cannot stop very long or you lose heading info).
Bob, WB4APR
On Fri, Aug 9, 2013 at 8:56 AM, Zach Leffke <zleffke@xx.xxx> wrote:
> Hello again everyone,
>
> I have received a couple of emails off list asking about
> details of how I'm planning to use the magnetometer for the azimuth
> feedback. Instead of individually replying I'm placing my response here so
> everyone gets the same info (skip to the end of this long winded email for
> the details). Before I get into that I want to address Bob's (WB4APR) note
> about the constant rate of these motors. Basically, I like the idea because
> of its simplicity. That's something I hadn't considered, but will look
> into. My logic there is run my system through a few dozen trials to really
> lock down the turn rate baseline. Then all I have to do is keep track of
> the amount of time and in which direction I'm telling the motors to turn,
> and voila I should know the azimuth/elevation. As Bob mentioned with the
> beamwidth of these antennas that should get me close enough.
>
>
>
> If I were only planning to use the system for tracking LEO birds at VHF/UHF
> frequencies, I would probably just go with that. However, I was slightly
> understating my goals when I initially brought up this issue. In addition
> to LEO birds, I plan to also use this system for UAV tracking and High
> Altitude Balloon Tracking. I am an EE graduate student at Virginia Tech and
> each semester I help out with an Undergraduate Lab with Aerospace and EE
> students that design and fly a high altitude balloon (generally with APRS
> tracking and some kind of camera/sensor suite payload). One of the
> professor in charge's (Dr. Dennis Sweeney, WA4LPR, some folks might know him
> for his filter design work among many other things) goals is to up the data
> rate in order to attempt a high speed real time data link. So in my own
> time I want to use this tracking pedestal for LEO tracking (and for my
> Master's Thesis prototype), but for this HAB project, the elevation can get
> quite high depending on the geometry of our chase scenario, and beamwidths
> can get quite small depending on the frequency we finally choose. In the
> end it might not matter much, but when we get to that point I want to at
> least have the OPTION for tight control over the pointing. This whole thing
> will likely get vehicle mounted in the bed of my pickup, and though I
> haven't completely thought out the details yet, My gut is telling me the use
> of a magnetometer for azimuth feedback could have a slight advantage because
> as the vehicle is moving the system could automatically compensate for the
> turning of the vehicle, where as a potentiometer type solution would not.
> With position updates from the HAB and a local GPS in the chase vehicle,
> calculation of Az/El to the target is pretty straight forward. Combine that
> with magnetometer feedback about the antennas' azimuth and elevation
> feedback from an accelerometer (which should also be somewhat "self
> compensating", say if the vehicle were moving up or down a hill), and I
> should be able to come up with a fairly sexy tracking pedestal that
> automatically compensates for the vehicle's motion to keep the antennas "on
> target."
>
>
>
> All that being said, here is my plan for the magnetometer implementation:
>
>
>
> I don't really have the details locked down yet, but I can give the overall
> plans. First I plan to use the HMC5883L from sparkfun. This device is
> $14.95 + Shipping and handling. It is a 3 axis magnetometer. When dealing
> with magnetometers it is important to understand whether or not your device
> is tilt compensated. This particular device is NOT tilt compensated. What
> that means is that it must be kept oriented parallel with the Earth (within
> say maybe + or - ten degrees or so). Assuming it remains oriented properly,
> the device will output (over I2C) the magnetic field strength in the X, Y,
> and Z directions. The Z direction is essentially pointed straight up at
> zenith (and should remain near zero since it is orthogonal to the earth's
> magnetic field). Also assuming no other strong magnetic fields exist near
> the sensor, it will detect Earth's magnetic field (the sensor just returns
> the highest magnetic field for a particular direction, so if other magnetic
> fields exist near the sensor, it can ruin the readings). In order to get
> the bearing, or azimuth, information one simply has to use the atan2
> function with the Y and X axes, here is the code snippet from some examples
> online: heading = atan2(scaled.YAxis, scaled.XAxis). The rest is just
> calibration and making sure the heading makes sense (i.e. if the heading is
> a negative number add 360 to get a 0 - 360 output). One issue too is that
> most satellite tracking programs return the TRUE heading or azimuth
> (reference to the North Pole) to the spacecraft. This magnetometer with
> produce a MAGNETIC azimuth (referenced to the magnetic pole). Thus one must
> compensate for the magnetic declination of the area of operation. The
> declination can be found online for each person's individual location and
> can be hard coded into the code to adjust the magnetic readout to a true
> readout.
>
>
>
> Since this device is not tilt compensated I plan to mount it on my azimuth
> base on a short boom that sticks straight out in front of the antenna
> assembly. It will be center mounted on a non-conductive extension (maybe
> two or three feet in front of the azimuth assembly). My logic here is to
> try to get the sensor as far away from the AC induction motors and other
> metals as I can. The AC motors will produce a strong magnetic field and if
> the sensor is near them, it will distort the readings.
>
>
>
> Thanks again to everyone that provided feedback for me. Below are a few
> links that should help out those who want more details. Keep in mind too
> that there is a plethora of information out there on these devices
> (tutorials and example code) and with the links below and some skillful
> Googling, anyone can found out everything they need to make one of these
> work.
>
>
>
> Sparkfun Link: https://www.sparkfun.com/products/10530
>
> Bildr Tutorial: http://bildr.org/2012/02/hmc5883l_arduino/
>
> K3NG's Arduino rotator control project:
> http://blog.radioartisan.com/yaesu-rotator-computer-serial-interface/
> (Thanks to Lizeth, N3YKF for pointing me in this direction)
>
> ---------------
>
>
>
> -Zach, KJ4QLP
>
>
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. Opinions expressed are those of the author.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 6
Date: Fri, 09 Aug 2013 23:23:24 -0700
From: Greg D <ko6th.greg@xxxxx.xxx>
To: "Ing. Pavel Milanes Costa" <co7wt@xxxxxx.xx.xx>
Cc: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Re: Rotator Positioning questions
Message-ID: <5205DC5C.7040001@xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii; format=flowed
I forget... Do these kinds of motors change their current draw
significantly when they stall? If they don't, a current probe may not be
a reliable stop indicator.
Also, regarding the challenge with 450 degree rotation... There's no
requirement that you actually use all 450 degrees. Just stick to 0-359
and it will make things a lot easier to start with. Once it's all
running, you can go for the fancy stuff.
Good luck with the project,
Greg KO6TH
Ing. Pavel Milanes Costa wrote:
> The "motor running/motor stop" signal will be a current probe on the
> AC 24V motor feeding wires down the control, as when the motor reach
> 0o or 450o it automatically switch's off
------------------------------
Message: 7
Date: Sat, 10 Aug 2013 11:45:39 -0400
From: Samudra Haque <samudra.haque@xxxxx.xxx>
To: blabber@xxxxx.xxxx Amsat-bb <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Cubesat 2013 Summer Workshop live video stream
Message-ID:
<CAJEM476xf3D+i7PBte1mPW7x4ajV0vfxcnSq1UH7fNFM6RofaA@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
FYI, I'm at Cubesat workshop @xxx.. Link for live video stream is provided
below.
http://www.ustream.tv/channel/cubesat-summer-workshop-2013?utm_campaign=www.cu
besat.org&utm_source=15530551&utm_medium=social
Samudra Haque, Ph.D Student
Dept of Mechanical and Aerospace Engineering
George Washington University
------------------------------
_______________________________________________
Sent via amsat-bb@xxxxx.xxx. Opinions expressed are those of the author.
Not an AMSAT member? Join now to support the amateur satellite program!
http://amsat.org/mailman/listinfo/amsat-bb
End of AMSAT-BB Digest, Vol 8, Issue 260
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