| |
CX2SA > SATDIG 12.06.12 21:10l 357 Lines 11875 Bytes #999 (0) @ WW
BID : AMSATBB7189
Read: GUEST
Subj: AMSAT-BB-digest V7 189
Path: IZ3LSV<IV3YXW<HB9TVW<ON4HU<CX2SA
Sent: 120612/1910Z @:CX2SA.SAL.URY.SA #:61347 [Salto] FBB7.00e $:AMSATBB7189
From: CX2SA@CX2SA.SAL.URY.SA
To : SATDIG@WW
Today's Topics:
1. Re: a couple tweaks to work AO-27 & SO-50 (Bill W1PA)
2. VK5ZAI on TV + SAREX 1992 Video (Trevor .)
3. Re: Asymmetric doppler curves? (g0mrf@xxx.xxxx
4. LVB Tracker not playing well with others (David Julian)
5. Re: Asymmetric doppler curves? (i8cvs)
6. NuSTAR Scheduled To Launch Tomorrow (B J)
----------------------------------------------------------------------
Message: 1
Date: Mon, 11 Jun 2012 16:03:39 -0400
From: "Bill W1PA" <w1pa@xxxxxxx.xxx>
To: <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Re: a couple tweaks to work AO-27 & SO-50
Message-ID: <BAY157-ds1928DF5915E7A8063CFA6698F70@xxx.xxx>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
I have to agree with Clint on this... don't overthink it. You only need a
compass or a map
to give you an idea where North is. If you have the antenna hand-held
or on a small tripod, you will use it more with your ears than eyes, like a
metal detector,
but pointed at the sky --- sweep back and forth, and also rotate the beam
around the boom
axis for polarization changes, and listen for maximum signal/minimum noise.
You will be
continually be updating this during the pass... use your ears.
I print out the AOS and LOS (acquisition and loss of signal) bearings, and
max elevation values
to give me approx. start and stop location, and to make sure my location
accounts for the tree line
and any buildings/obstacles. But I am still sweeping back and forth with the
Arrow as the bird
pops up over the horizon, and then optimize it when I hear the bird.
Spend the money on a good accurate watch and a voice/tape recorder. :-)
Bill W1PA
------------------------------
Message: 2
Date: Mon, 11 Jun 2012 21:09:50 +0100 (BST)
From: "Trevor ." <m5aka@xxxxx.xx.xx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] VK5ZAI on TV + SAREX 1992 Video
Message-ID:
<1339445390.61215.YahooMailClassic@xxxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=utf-8
Tony Hutchison VK5ZAI On TV Show, I believe from 2008 ?
http://www.uk.amsat.org/?p=8161
Jay Leno - SAREX Shuttle Amateur Radio Experiment 1992 Video
http://www.uk.amsat.org/?p=8172
73 Trevor M5AKA
AMSAT-UK International Space Colloquium Sept. 15-16
http://www.uk.amsat.org/colloquium/twelve
Booking at http://tinyurl.com/Colloquium2012Booking
----
------------------------------
Message: 3
Date: Mon, 11 Jun 2012 18:33:56 -0400 (EDT)
From: g0mrf@xxx.xxx
To: domenico.i8cvs@xxx.xxx amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Re: Asymmetric doppler curves?
Message-ID: <8CF16396C42E361-1888-16E9C@xxxxxxxxxxxx.xxxxxx.xxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
Dear Domenico, Dave, Miguel Trevor and Ivo.
Thank you all for your thoughts and references. James Miller's Plan 13
etc is an excellent resource as, I discovered is Ivo's thesis.
I have reached the conclusion that extracting more information from
Doppler measurements in the limited time available may be considered a
little tenuous. A reasonable approximation of satellite velocity and
altitude should be straightforward. However I think trying to measure
the Earths rotational speed suffers from one major source of error and
that is the stability / calibration of the satellite transmitter and
the groundstation receiver. To accurately measure the difference or
asymmetry in Doppler between AOS and LOS (e.g. AOS may be fc +10,000Hz
while LOS could be fc - 10,200) depends entirely on knowing the exact
center frequency of transmission. Without that, the valid data becomes
lost within the errors. However, hopefully some of the students will
find it an inspiring addition to their study of gravitational fields.
Regards and thanks
David
-----Original Message-----
From: i8cvs <domenico.i8cvs@xxx.xx>
To: Amsat - BBs <amsat-bb@xxxxx.xxx>; G0MRF <G0MRF@xxx.xxx>
Sent: Sun, 10 Jun 2012 3:25
Subject: Re: [amsat-bb] Asymetric doppler curves?
Hi David, G0MRF
If you read the old issues of OSCAR-News from AMSAT-UK you
will realize that a serious traking program like PLAN-10 written
by James Miller G3RUH take into calculation all perturbations due
to inclination and velocity of the satellite due to Earths rotational
speed added / subtracted at either end of the pass and so doppler.
73" de
i8CVS Domenico
----- Original Message -----
From: <g0mrf@xxx.xxx>
To: <amsat-bb@xxxxx.xxx>
Sent: Sunday, June 10, 2012 1:20 AM
Subject: [amsat-bb] Asymetric doppler curves?
> Hi all.
>
> I'm doing a small demonstration for a physics class using Doppler
> measurements on the HO-68 beacon.
>
> Hopefully we'll be able to calculate spacecraft velocity and from that
> result, go on to calculate orbit altitude. However, in thinking
about
> this I realised that there is a potential source of error. We are
not
> stationary !! - OK, it's obvious really, but I've never seen this
> mentioned in topics like Doppler correction programs and I've not seen
> it visually in displayed Doppler curves.
>
> The issue is that while a spacecraft with zero eccentricity will have
a
> constant velocity, the speed relative to an observer on Earth at AOS
> and LOS will be different for each half of the pass depending on the
> observers latitude and the inclination of the satellite.
>
> The worse case would be something travelling East to West or West to
> East as the velocity of the satellite would have the Earths rotational
> speed added / subtracted at either end of the pass.
>
> Has anyone seen this effect? Perhaps on the ISS? I think it could
be
> as much as 7% which may be measurable. - But not on HO-68 which is
> polar orbiting....
>
> Just want to make the most of my 45 minutes.
>
> Thanks
>
> David G0MRF
>
> _______________________________________________
> 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: 4
Date: Mon, 11 Jun 2012 17:19:31 -0700 (PDT)
From: David Julian <ddjulian54@xxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] LVB Tracker not playing well with others
Message-ID:
<1339460371.37468.YahooMailClassic@xxxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=iso-8859-1
I picked up a LVB Tracker at Dayton last year and am just now getting it set
up. No problem calibrating it to the G-5400B. All controlls work as
expected. I connected the USB cable and loaded the drivers per the FTDI
documentation but am having issues. As soon as I access the port?from
?Hyperterminal or SATPC32 I get a short "bluescreen of death" and the laptop
re-starts. Internal inspection doesn't show anything obvious. I have not
tried pulling the USB and installing?an RS232 chip. I have tried
un-installing and re-installing the drivers and get the same results even
with a different PC. Any ideas?
?
Thanks
Dave Julian WB9YIG
------------------------------
Message: 5
Date: Tue, 12 Jun 2012 11:25:37 +0200
From: "i8cvs" <domenico.i8cvs@xxx.xx>
To: "Amsat - BBs" <amsat-bb@xxxxx.xxx>, <G0MRF@xxx.xxx>
Subject: [amsat-bb] Re: Asymmetric doppler curves?
Message-ID: <000001cd487d$5e2c8420$0401a8c0@xxxxxx>
Content-Type: text/plain; charset="iso-8859-1"
Hi David, G3MRF
I agree with you and I believe very difficult to explain accurately
the difference or asymmetry in Doppler between AOS and LOS
to students in only 45 minutes because in my experience after
60 minutes of conference the stuents are already tired.
73" de
i8CVS Domenico
----- Original Message -----
From: <g0mrf@xxx.xxx>
To: <domenico.i8cvs@xxx.xx>; <amsat-bb@xxxxx.xxx>
Sent: Tuesday, June 12, 2012 12:33 AM
Subject: Re: [amsat-bb] Asymmetric doppler curves?
Dear Domenico, Dave, Miguel Trevor and Ivo.
Thank you all for your thoughts and references. James Miller's Plan 13
etc is an excellent resource as, I discovered is Ivo's thesis.
I have reached the conclusion that extracting more information from
Doppler measurements in the limited time available may be considered a
little tenuous. A reasonable approximation of satellite velocity and
altitude should be straightforward. However I think trying to measure
the Earths rotational speed suffers from one major source of error and
that is the stability / calibration of the satellite transmitter and
the groundstation receiver. To accurately measure the difference or
asymmetry in Doppler between AOS and LOS (e.g. AOS may be fc +10,000Hz
while LOS could be fc - 10,200) depends entirely on knowing the exact
center frequency of transmission. Without that, the valid data becomes
lost within the errors. However, hopefully some of the students will
find it an inspiring addition to their study of gravitational fields.
Regards and thanks
David
-----Original Message-----
From: i8cvs <domenico.i8cvs@xxx.xx>
To: Amsat - BBs <amsat-bb@xxxxx.xxx>; G0MRF <G0MRF@xxx.xxx>
Sent: Sun, 10 Jun 2012 3:25
Subject: Re: [amsat-bb] Asymetric doppler curves?
Hi David, G0MRF
If you read the old issues of OSCAR-News from AMSAT-UK you
will realize that a serious traking program like PLAN-10 written
by James Miller G3RUH take into calculation all perturbations due
to inclination and velocity of the satellite due to Earths rotational
speed added / subtracted at either end of the pass and so doppler.
73" de
i8CVS Domenico
----- Original Message -----
From: <g0mrf@xxx.xxx>
To: <amsat-bb@xxxxx.xxx>
Sent: Sunday, June 10, 2012 1:20 AM
Subject: [amsat-bb] Asymetric doppler curves?
> Hi all.
>
> I'm doing a small demonstration for a physics class using Doppler
> measurements on the HO-68 beacon.
>
> Hopefully we'll be able to calculate spacecraft velocity and from that
> result, go on to calculate orbit altitude. However, in thinking
about
> this I realised that there is a potential source of error. We are
not
> stationary !! - OK, it's obvious really, but I've never seen this
> mentioned in topics like Doppler correction programs and I've not seen
> it visually in displayed Doppler curves.
>
> The issue is that while a spacecraft with zero eccentricity will have
a
> constant velocity, the speed relative to an observer on Earth at AOS
> and LOS will be different for each half of the pass depending on the
> observers latitude and the inclination of the satellite.
>
> The worse case would be something travelling East to West or West to
> East as the velocity of the satellite would have the Earths rotational
> speed added / subtracted at either end of the pass.
>
> Has anyone seen this effect? Perhaps on the ISS? I think it could
be
> as much as 7% which may be measurable. - But not on HO-68 which is
> polar orbiting....
>
> Just want to make the most of my 45 minutes.
>
> Thanks
>
> David G0MRF
>
> _______________________________________________
> 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: Tue, 12 Jun 2012 18:26:05 +0000
From: B J <va6bmj@xxxxx.xxx>
To: amsat-bb <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] NuSTAR Scheduled To Launch Tomorrow
Message-ID:
<CAP7QzkMLbrdMHZZdmdSsK6r1XddENSPKVG=8LS4prwFyCiM5zQ@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
http://www.nasa.gov/mission_pages/nustar/main/index.html
73s
Bernhard VA6BMJ @ DO33FL
------------------------------
_______________________________________________
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 7, Issue 189
****************************************
Read previous mail | Read next mail
| |
