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CX2SA > SATDIG 28.09.09 21:04l 403 Lines 14115 Bytes #999 (0) @ WW
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From: CX2SA@CX2SA.LAV.URY.SA
To : SATDIG@WW
Today's Topics:
1. Re: All Satellites (Alan P. Biddle) (John B. Stephensen)
2. Re: SAT32PC issue-sat drops off (David Wing)
3. kpc9612 (Mr Jeffrey L Ross)
4. FO-29 (WILLIAMS MICHAEL)
5. Cute 1.7 Re-Entry (John Heath)
6. Re: Satellite Orbit Prediction in Python (Mark VandeWettering)
7. Re: Cute 1.7 Re-Entry (Nigel Gunn G8IFF/W8IFF)
8. Re: Satellite Orbit Prediction in Python (Bryan Klofas)
----------------------------------------------------------------------
Message: 1
Date: Mon, 28 Sep 2009 15:19:28 -0000
From: "John B. Stephensen" <kd6ozh@xxxxxxx.xxx>
Subject: [amsat-bb] Re: All Satellites (Alan P. Biddle)
To: "Gordon JC Pearce" <gordonjcp@xxxx.xxx>, <amsat-bb@xxxxx.xxx>
Message-ID: <A55DBF8B4C4648A0B1C719EE1979DD0F@xxxxxxxxxxxxxx>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
FDMDV uses a 1400 bps codec, occupies only 1100 Hz and operates with any SSB
transceiver. Comunications doesn't have to be full duplex. At 12-16 kbps the
satellite and ground stations could alternate with short bursts of voice or
text. This wouldn't fit in a 2.4 kHz SSB bandwidth but would require a 16-20
kHz wide filter or use of a transverter and a simple SDR radio like the
SoftRock.
73,
John
KD6OZH
----- Original Message -----
From: "Gordon JC Pearce" <gordonjcp@xxxx.xxx>
>
>> KD6OZH's mentioning of a 1200 bps voice codec is very interesting,
>> too. I see that DSTAR's AMBE is down to 2000 with error correction,
>> and Speex operates down to 2000, too, though I think without error
>> correction. (I find the latter much more engaging as a ham, since it
>> is open source.) It would be a hoot to do a voice conference over the
>> Internet using a sample of low bitrate codecs and just get a sense of
>> what might be possible. One downside of voice is that it would occupy
>> the transponder far more than messaging, and Bob's favorable power
>> calculations would need to be estimated downwards.
>
> Would the packet satellite be capable of bent-pipe operation though?
> You'd need to transmit and receive simultaneously to get that working.
> I'd far prefer to use Speex rather than the locked-down proprietary AMBE
> codecs.
------------------------------
Message: 2
Date: Mon, 28 Sep 2009 08:24:02 -0700
From: "David Wing" <david@xxxxxx.xxx>
Subject: [amsat-bb] Re: SAT32PC issue-sat drops off
To: <amsat-bb@xxxxx.xxx>
Message-ID: <175A1C86066C47769093186D3012809A@xxxxx>
Content-Type: text/plain; charset="us-ascii"
Craig,
I have not had this problem but have heard you mention it before. I did
have a pass come up way off frequency and not sure why that happened...has
only happened once as far as I remember.
Hope you catch you on VO-52 soon.
David
K6CDW
-----Original Message-----
From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
Behalf Of D. Craig Fox
Sent: Sunday, September 27, 2009 8:40 PM
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] SAT32PC issue-sat drops off
hello all on this distinguished listserv!
I love staying in the loop thru this listerv. But I digress. Recently I
notice that VO52 has been getting dropped off of my sat 32 pc sat list. I
have to make a point of adding it back on. This never used to happen.
Any clues/suggestions? Thanks in advance!
Craig
N6RSX
AMSAT # 36607
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------------------------------
Message: 3
Date: Mon, 28 Sep 2009 11:38:13 -0400
From: "Mr Jeffrey L Ross" <radiooperator@xxxxxxx.xxx>
Subject: [amsat-bb] kpc9612
To: "amsat" <amsat-bb@xxxxx.xxx>
Message-ID: <D6A247D11571494FBB9C8E5ADE038B6E@xxxxxxxxxxxxxxxx>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
hi all, the kpc9612 will not do 300 baud on one port and 1200 on the other.
what were they thinking when they made this. geee.
all along thought it did.
kc8gkf
------------------------------
Message: 4
Date: Mon, 28 Sep 2009 09:44:15 -0700 (PDT)
From: WILLIAMS MICHAEL <k9qho6762@xxxxxxxxx.xxx>
Subject: [amsat-bb] FO-29
To: amsat-bb@xxxxx.xxx
Message-ID: <753611.60509.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=iso-8859-1
When posting? to AMSAT-BB, the high lighting and underlining must have been
stripped.
?
Here is what I high lighted and underlined.
?
1. FO-29 is in the "high shade rate period" now.
?
2. "high shade rate" and by the rise of the internal
resistance of the deterioration of the battery and by the influence of
the temperature of the battery.
?
3.it is designed to turn on a transmitter automatically.
However malfunction occurred for this function in 2007.
4. The transponder has been worked without control command from control
station from summer of 2008.
?
5. ***From this , We decided that we make the operation schedule plan, and
manage the limit of the operative number of times in one day like last
time to keep the electricity income and expenditure untill improve the
"shade rate" which is in January, 2010.
?
6. The transmitter becomes OFF by UVC automatically in the eclipse.
?
All the best,
?
Mike (K9QHO)
------------------------------
Message: 5
Date: Mon, 28 Sep 2009 17:07:17 +0000 (GMT)
From: John Heath <g7hia@xxxxxxxxxx.xxx>
Subject: [amsat-bb] Cute 1.7 Re-Entry
To: Amsat <amsat-bb@xxxxx.xxx>
Message-ID: <218593.97975.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset="iso-8859-1"
Hi
Based on?day 271 keps from Celestrak the Perigee?height? for Cute 1.7 Object
28941 has now dropped below 300km.
Re-entry probably early October. Anyone care to?predict the date and time?
If you would, ?how about sending it to me off list.? g7hia@xxxxxxxxxx.xxx I
will complile a table and provide a small prize for the person who is nearest.
Closing date midnight utc last day of September.
73 John G7HIA
------------------------------
Message: 6
Date: Mon, 28 Sep 2009 10:11:23 -0700
From: Mark VandeWettering <kf6kyi@xxxxx.xxx>
Subject: [amsat-bb] Re: Satellite Orbit Prediction in Python
To: Joseph Armbruster <josepharmbruster@xxxxx.xxx>
Cc: amsat-bb@xxxxx.xxxx k6hx@xxxx.xxx
Message-ID: <4AC0EE3B.2000701@xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Joseph Armbruster wrote:
> Awesome stuff!! I'll have to check out this library tonight. I
> started hacking at something similar but started digging into the
> internals of SGP4/SDP4, then got distracted and never finished. If
> you have a rotator, it'd be a cool quick project to slap pyserial on
> there and control your rotator. It'd be pretty awesome to have a Kep
> to Rotator Control in about 10 lines of code :-)
>
> Joe
That reminds me, I should give thanks to Howard, G6LVB. I've never met
Howard, but his G6LVB tracker project first put me onto G3RUH's Plan 13
work. Howards PIC based tracker implements Plan 13 to do automatic
antenna guiding, and seems very cool.
I have actually experimented with using my library to predict and
compensate for Doppler shift using my FT-817. I used pyserial to send
out frequency change commands as documented in the FT-817 manual. It
worked reasonably well. For example, following is a simple visual
display of a pass of the three small satellites COMPASS-1, CUTE-1.7 APD
and SEEDS that I did back on Jun 13, 2008.
WARNING: this JPG is 1.7Mb, and 1600x8000 or so in size. Don't blame
me if your computer melts trying to display it.
http://brainwagon.org/wp-content/uploads/2008/06/three.jpg
You can see COMPASS-1 at the beginning, with its sharply whistling
tones. Then CUTE will step in, and finally SEEDS. You can clearly
see the steps in frequency every second or so.
If you'd rather have the audio, you can get it here:
http://brainwagon.org/wp-content/uploads/2008/06/threefer-20080613.mp3
73 Mark K6HX
------------------------------
Message: 7
Date: Mon, 28 Sep 2009 17:36:55 +0000
From: Nigel Gunn G8IFF/W8IFF <nigel@xxxxx.xxx>
Subject: [amsat-bb] Re: Cute 1.7 Re-Entry
To: John Heath <g7hia@xxxxxxxxxx.xxx>
Cc: Amsat <amsat-bb@xxxxx.xxx>
Message-ID: <4AC0F437.10206@xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8; format=flowed
I posted the following on this a week or so ago:
Spacetrack is predicting that CUTE 1.7 will decay on 10th October.
My predix software predicts that the first time the satellite hits terra
firma will be 19th December.
What do others think?
John Heath wrote:
> Hi
>
> Based on day 271 keps from Celestrak the Perigee height for Cute 1.7
Object 28941 has now dropped below 300km.
>
> Re-entry probably early October. Anyone care to predict the date and time?
>
> If you would, how about sending it to me off list. g7hia@xxxxxxxxxx.xxx
I will complile a table and provide a small prize for the person who is
nearest.
>
> Closing date midnight utc last day of September.
>
>
> 73 John G7HIA
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> 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
>
>
> ------------------------------------------------------------------------
>
>
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>
--
Nigel A. Gunn, 1865 El Camino Drive, Xenia, OH 45385-1115, USA. tel +1 937
825 5032
Amateur Radio G8IFF W8IFF (was KC8NHF), e-mail nigel@xxxxx.xxx www
http://www.ngunn.net
Member of ARRL, GQRP #11396, QRPARCI #11644, SOC #548, Flying Pigs QRP
Club International #385,
Dayton ARA #2128, AMSAT-NA LM-1691, AMSAT-UK 0182, MKARS, ALC,
GCARES, XWARN.
------------------------------
Message: 8
Date: Mon, 28 Sep 2009 11:41:33 -0700
From: Bryan Klofas <bklofas@xxxxx.xxx>
Subject: [amsat-bb] Re: Satellite Orbit Prediction in Python
To: amsat-bb@xxxxx.xxx
Message-ID: <4AC1035D.1010600@xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hey Mark--
We also use pyephem for web-based pass times calculations at Cal Poly.
http://mstl.atl.calpoly.edu/~ops/passtimes/
Source is here, but it was written a few years back, and uses the older
(now depreciated) ephem.Body attributes. It also sometimes has trouble
with the formatting on the webpage, although that may be a firefox bug,
I'm not sure.
http://mstl.atl.calpoly.edu/~ops/passtimes/passtimes.py
--
Bryan Klofas, KF6ZEO
Mark VandeWettering wrote:
> I just thought I'd drop a quick note here about some fun I've been
> having today with satellite orbit prediction in Python. When I
> started mucking around with satellites, I used "predict", which was
> pretty good, but at some point I wanted to answer some questions which
> weren't easy to answer using predict. Questions like "when will
> AO-51 be visible from both my home in CM87 and locations in Hawaii",
> or "what was the radius of the circle of visibility for AO-7 compared
> to ISS"?
>
> Luckily, I'm a programmer. In fact, I'm a programmer who programs
> for fun. So, I did a bit of research, and then coded up a version of
> G3RUH's "Plan 13" algorithm in Python, and then wrote some scripts to
> download elements from celestrak, and then a simple one to print data
> on the next pass of any named satellite. And, they worked pretty
> good. I've used them for the last year or so to do all my pass
> predictions. But there are still a couple of minor issues with the
> library. It didn't handle geosynchronous satellites very well. It
> implemented only the most basic of orbital models. I was never
> confident that the "is this satellite in eclipse" stuff working
> exactly right.
>
> Luckily though, it turns out that someone else has been busy writing a
> more complete library: PyEphem http://rhodesmill.org/pyephem/
>
> It's a library whose primary purpose is to calculate the positions of
> astronomical objects. I've used it a couple of times to (for
> instance) figure out the size of Mars compared to Jupiter, and found
> it very easy to use. But today, I realized that it had a full
> implementation of the SGP4 and SDP4 orbital models built in, and could
> be used to predict satellite passes. As a proof of concept, I
> hacked together a 23 line script that could print the details of
> upcoming ISS passes. It seems to work great, and is really quite
> easy to use.
>
> You can find some of the simple example code at my blog:
>
>
http://brainwagon.org/2009/09/27/how-to-use-python-to-predict-satellite-locati
ons/
>
> I'll probably be porting all of my existing scripts to use this soon.
> In the mean time, if you have a similar task, you might look to it to
> solve your custom satellite prediction problems.
>
> 73 Mark K6HX
> _______________________________________________
> 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
------------------------------
_______________________________________________
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 4, Issue 505
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