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CX2SA > SATDIG 25.10.10 18:04l 941 Lines 32359 Bytes #999 (0) @ WW
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To : SATDIG@WW
Today's Topics:
1. Re: AO-51 short experiment (Vince Fiscus, KB7ADL)
2. Re: AO-51 short experiment (Alan P. Biddle)
3. Re: AO-51 short experiment (Larry Gerhardstein)
4. Re: AO-51 short experiment (Bob Herrell)
5. Fwd: Next "HV Satcom" Net (Stuart Balanger)
6. Re: AO-51 short experiment (John Neeley)
7. WTB G-5500 control box (Andrew Glasbrenner)
8. Re: can RF change the orientation of a satellite? (Daniel Schultz)
9. Why We Do What We Do - Part 19 (Clint Bradford)
10. HO-68 Schedule 24-31 Oct 2010 (Alan Kung)
11. Re: can RF change the orientation of a satellite?
(Auke de Jong, VE6PWN)
12. Re: Sept Financials (Martha)
13. QSL cards mailed today, QSLs for DM30 activity on Saturday,
DM31? (Patrick STODDARD (WD9EWK/VA7EWK))
----------------------------------------------------------------------
Message: 1
Date: Sun, 24 Oct 2010 14:51:26 -0700
From: "Vince Fiscus, KB7ADL" <vlfiscus@xxx.xxx>
Subject: [amsat-bb] Re: AO-51 short experiment
To: amsat-bb@xxxxx.xxx
Message-ID: <5.2.1.1.2.20101024142831.00bdfd00@xxx.xxxxxxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
At 11:09 AM 10/24/2010 -0700, Bob Herrell <nk7i@xxxxx.xxx> wrote:
>Any chance we could get the ISS to change their packet frequency?
>
>73,
>Bob Herrell
>AJ5C
No,
The APRS QRM'ers with their unattended beacons are the problem. Years ago
I said APRS was bad, but I never thought it would ever get this
bad. Things definitely aren't like they were in the MIR days, when you
could make multiple contacts a pass with minimal equipment. I could build
a setup for packet that every single one of my packets would get through,
but what good would the do? So I could have a QSO with myself? So I give up.
The APRS'ers should build a dedicated satellite just for APRS, and their
QRM should be limited to just that one satellite, unless they won't to
build more.
Hell, I'd even donate to it just to clean things up!
KB7ADL
------------------------------
Message: 2
Date: Sun, 24 Oct 2010 15:45:18 -0500
From: "Alan P. Biddle" <APBIDDLE@xxxxxx.xxx>
Subject: [amsat-bb] Re: AO-51 short experiment
To: "'Bob Herrell'" <nk7i@xxxxx.xxx>, <amsat-bb@xxxxx.xxx>
Message-ID: <A6BA992DEE4B4E3C822EFE1BA5D4FC6D@xxxxxx>
Content-Type: text/plain; charset="us-ascii"
Bob,
145.825 is the "established" space APRS frequency, and has been/is used by
more than just the ISS for years. There are other APRS satellites which are
intermittently active on the same frequency, and I expect there will be
others in the future. I can't address the formal coordination issue, but
anything with an uplink on that frequency is guaranteed to have problems.
The only question is whether those problems are tolerable. There is little
to no APRS activity on that frequency over most of the world, and then there
is the question of both HO-68 and the ISS being in the same footprint. The
HO-68 has an inclination of about 102 degrees, the ISS about half that.
Finally, the ISS is not active on that frequency 24/7. It operates on other
frequencies for voice and SSTV, and is often QRT completely due to other
operations. In an imperfect world, it looks like a reasonable tradeoff,
though other evaluations are certainly possible.
The problem of unattended APRS beacons does cut both ways. There are some
daylight-only APRS satellites. When they enter periods of extended
illumination, they can be commanded from their default modes. However, even
a single "braaap" can pull the DC busses low enough that the command
stations need to start over again. WB4APR has lamented this problem, with
specific calls, in other venues. Looking at some of the paths, both in
Drew's example and my reception, there are stations whose paths have not
been updated for years.
The sort of courtesy/coordination issue is not limited to space operations.
A ham relatively local to me fired up a propagation beacon on 30 meters this
month. It is/was within 200 HZ of an APRS frequency which has been in use
for some time. Quite a fight over who "owns" the frequency. ;)
Alan
WA4SCA
------------------------------
Message: 3
Date: Sun, 24 Oct 2010 15:00:59 -0600
From: Larry Gerhardstein <W7IN@xxxxxxx.xxx>
Subject: [amsat-bb] Re: AO-51 short experiment
To: APBIDDLE@xxxxxxx.xxx
Cc: amsat-bb@xxxxx.xxxx "Alan P. Biddle" <APBIDDLE@xxxxxx.xxx>
Message-ID: <4CC49E8B.7080603@xxxxxxx.xxx>
Content-Type: text/plain; charset="iso-8859-1"
No one 'owns the frequency' and if in-place coordination can not resolve
the issue, the newest user should consider moving out of the required
bandpass. Was the first user ever coordinated? ~~Larry W7IN~~
On 10/24/2010 2:45 PM, Alan P. Biddle wrote:
> Bob,
>
> 145.825 is the "established" space APRS frequency, and has been/is used by
> more than just the ISS for years. There are other APRS satellites which are
> intermittently active on the same frequency, and I expect there will be
> others in the future. I can't address the formal coordination issue, but
> anything with an uplink on that frequency is guaranteed to have problems.
> The only question is whether those problems are tolerable. There is little
> to no APRS activity on that frequency over most of the world, and then there
> is the question of both HO-68 and the ISS being in the same footprint. The
> HO-68 has an inclination of about 102 degrees, the ISS about half that.
> Finally, the ISS is not active on that frequency 24/7. It operates on other
> frequencies for voice and SSTV, and is often QRT completely due to other
> operations. In an imperfect world, it looks like a reasonable tradeoff,
> though other evaluations are certainly possible.
>
> The problem of unattended APRS beacons does cut both ways. There are some
> daylight-only APRS satellites. When they enter periods of extended
> illumination, they can be commanded from their default modes. However, even
> a single "braaap" can pull the DC busses low enough that the command
> stations need to start over again. WB4APR has lamented this problem, with
> specific calls, in other venues. Looking at some of the paths, both in
> Drew's example and my reception, there are stations whose paths have not
> been updated for years.
>
> The sort of courtesy/coordination issue is not limited to space operations.
> A ham relatively local to me fired up a propagation beacon on 30 meters this
> month. It is/was within 200 HZ of an APRS frequency which has been in use
> for some time. Quite a fight over who "owns" the frequency. ;)
>
> Alan
> WA4SCA
>
>
>
>
> _______________________________________________
> 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: Sun, 24 Oct 2010 15:02:24 -0700 (PDT)
From: Bob Herrell <nk7i@xxxxx.xxx>
Subject: [amsat-bb] Re: AO-51 short experiment
To: amsat-bb@xxxxx.xxx
Message-ID: <756959.69620.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
Alan,
I agree with you totally. It is going to be an ongoing problem and unless
individual operators take responsibility for their emissions, it is going to
continue. Even with coordination the frequency is still not owned by any
particular station. It is just common courtesy that we need to show to each
other. Are these APRS stations just beaconing in hopes of hitting the ISS or
are
they in use for normal APRS? I don't see 145.825MHz being used as a
terrestrial
frequency. I can understand the problem when HO-68 and the ISS are in the same
footprint, but to run a station continuously on 145.825MHz is crazy. I do send
packets to the ISS myself, but ONLY when it is in view and turned on. It all
boils down to the old idea of "Listen before you talk".
73,
Bob
AJ5C
________________________________
From: Alan P. Biddle <APBIDDLE@xxxxxx.xxx>
To: Bob Herrell <nk7i@xxxxx.xxx>; amsat-bb@xxxxx.xxx
Sent: Sun, October 24, 2010 3:45:18 PM
Subject: RE: [amsat-bb] Re: AO-51 short experiment
Bob,
145.825 is the "established" space APRS frequency, and has been/is used by
more than just the ISS for years. There are other APRS satellites which are
intermittently active on the same frequency, and I expect there will be
others in the future. I can't address the formal coordination issue, but
anything with an uplink on that frequency is guaranteed to have problems.
The only question is whether those problems are tolerable. There is little
to no APRS activity on that frequency over most of the world, and then there
is the question of both HO-68 and the ISS being in the same footprint. The
HO-68 has an inclination of about 102 degrees, the ISS about half that.
Finally, the ISS is not active on that frequency 24/7. It operates on other
frequencies for voice and SSTV, and is often QRT completely due to other
operations. In an imperfect world, it looks like a reasonable tradeoff,
though other evaluations are certainly possible.
The problem of unattended APRS beacons does cut both ways. There are some
daylight-only APRS satellites. When they enter periods of extended
illumination, they can be commanded from their default modes. However, even
a single "braaap" can pull the DC busses low enough that the command
stations need to start over again. WB4APR has lamented this problem, with
specific calls, in other venues. Looking at some of the paths, both in
Drew's example and my reception, there are stations whose paths have not
been updated for years.
The sort of courtesy/coordination issue is not limited to space operations.
A ham relatively local to me fired up a propagation beacon on 30 meters this
month. It is/was within 200 HZ of an APRS frequency which has been in use
for some time. Quite a fight over who "owns" the frequency. ;)
Alan
WA4SCA
------------------------------
Message: 5
Date: Sun, 24 Oct 2010 18:37:52 -0400
From: Stuart Balanger <wa2bss@xxxxx.xxx>
Subject: [amsat-bb] Fwd: Next "HV Satcom" Net
To: AMSAT-BB@xxxxx.xxxx kt2d@xxxx.xxx
Message-ID:
<AANLkTi=jFWtnZeqRYPRqXGt4LTrky-MFOVnV6S+xAH0j@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
*By the way, for those who checked in via Echolink
2 weeks ago 10/07), sorry abt. the Interferance,
& hope we can have a hassle=free net this Thur.
(Bob), FYI; the next Nt. Beacon "In Person "meeting is Nov. 9, Po'k
gallaria Mall (7PM;Community room!)
73,.Stu (WA2BSS; Director)
*
---------- Forwarded message ----------
From: Stuart Balanger <wa2bss@xxxxx.xxx>
Date: Fri, Oct 22, 2010 at 7:00 PM
Subject: Next "HV Satcom" Net
To: ans-editor@xxxxx.xxx
*Hi all,
The next "HV Satcom" net is Thur. Oct. 28 2 8PM (EDT) (or 2400 UTC)
on the 146.970 Mt. Beacon ARC 2 meter Repeater, w/ a Echolink node
of N2EYH-L
More info: www.hvsatcom.org or E-Mail; wa2aqh@xxxxx.xxx
73,.Stu (WA2BSS:
Director)
PS Hope this isn't too late, & happy "Halloween"!
*
------------------------------
Message: 6
Date: Sun, 24 Oct 2010 16:53:14 -0700 (PDT)
From: John Neeley <w6zkh@xxx.xxx>
Subject: [amsat-bb] Re: AO-51 short experiment
To: Bob Herrell <nk7i@xxxxx.xxx>, amsat-bb@xxxxx.xxx
Message-ID: <339159.61361.qm@xxxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
Sorta on the same order as the 432mhz ground station terrestrial stations
messing with AO-7 in mode B. There though we are blessed with extra bandwidth
on the linear translator vs single channel FM repeater. HO-68 is a PITA to
work on FM for me, but great linear bird.
John W6ZKH
________________________________
From: Bob Herrell <nk7i@xxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Sent: Sun, October 24, 2010 3:02:24 PM
Subject: [amsat-bb] Re: AO-51 short experiment
Alan,
I agree with you totally. It is going to be an ongoing problem and unless
individual operators take responsibility for their emissions, it is going to
continue. Even with coordination the frequency is still not owned by any
particular station. It is just common courtesy that we need to show to each
other. Are these APRS stations just beaconing in hopes of hitting the ISS or
are
they in use for normal APRS? I don't see 145.825MHz being used as a
terrestrial
frequency. I can understand the problem when HO-68 and the ISS are in the same
footprint, but to run a station continuously on 145.825MHz is crazy. I do send
packets to the ISS myself, but ONLY when it is in view and turned on. It all
boils down to the old idea of "Listen before you talk".
73,
Bob
AJ5C
________________________________
From: Alan P. Biddle <APBIDDLE@xxxxxx.xxx>
To: Bob Herrell <nk7i@xxxxx.xxx>; amsat-bb@xxxxx.xxx
Sent: Sun, October 24, 2010 3:45:18 PM
Subject: RE: [amsat-bb] Re: AO-51 short experiment
Bob,
145.825 is the "established" space APRS frequency, and has been/is used by
more than just the ISS for years. There are other APRS satellites which are
intermittently active on the same frequency, and I expect there will be
others in the future. I can't address the formal coordination issue, but
anything with an uplink on that frequency is guaranteed to have problems.
The only question is whether those problems are tolerable. There is little
to no APRS activity on that frequency over most of the world, and then there
is the question of both HO-68 and the ISS being in the same footprint. The
HO-68 has an inclination of about 102 degrees, the ISS about half that.
Finally, the ISS is not active on that frequency 24/7. It operates on other
frequencies for voice and SSTV, and is often QRT completely due to other
operations. In an imperfect world, it looks like a reasonable tradeoff,
though other evaluations are certainly possible.
The problem of unattended APRS beacons does cut both ways. There are some
daylight-only APRS satellites. When they enter periods of extended
illumination, they can be commanded from their default modes. However, even
a single "braaap" can pull the DC busses low enough that the command
stations need to start over again. WB4APR has lamented this problem, with
specific calls, in other venues. Looking at some of the paths, both in
Drew's example and my reception, there are stations whose paths have not
been updated for years.
The sort of courtesy/coordination issue is not limited to space operations.
A ham relatively local to me fired up a propagation beacon on 30 meters this
month. It is/was within 200 HZ of an APRS frequency which has been in use
for some time. Quite a fight over who "owns" the frequency. ;)
Alan
WA4SCA
_______________________________________________
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: 7
Date: Sun, 24 Oct 2010 20:19:37 -0400
From: Andrew Glasbrenner <glasbrenner@xxxxxxxxxx.xxx>
Subject: [amsat-bb] WTB G-5500 control box
To: Amsat-BB <amsat-bb@xxxxx.xxx>
Message-ID: <4CC4CD19.3050203@xxxxxxxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Would anyone happen to have a G-5500 control box by itself that they
would like to sell?
73, Drew KO4MA
------------------------------
Message: 8
Date: Sun, 24 Oct 2010 21:15:04 -0400
From: "Daniel Schultz" <n8fgv@xxx.xxx>
Subject: [amsat-bb] Re: can RF change the orientation of a satellite?
To: <amsat-bb@xxxxx.xxx>
Message-ID: <636oJyBoe3184S02.1287969304@xxxxx.xxx.xxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
It makes sense. Satellites are subject to solar radiation pressure from
absorption of sunlight, they are also subject to radiation pressure from
emission of RF radiation. The wavelength of the radiation does not enter into
this calculation so the pressure from radio frequency radiation is the same as
that of visible light radiation.
Radiation pressure is the electromagnetic power flux density divided by the
speed of light. If a 100 watt transponder emits RF in a narrow beam from a 1
square meter antenna, the radiation pressure on the satellite will be 100
watts / (1 square meter * 3E8 meters/sec) = 0.33 micropascals. The force on a
1 square meter antenna will thus be 0.33 micronewtons. This is not the same as
ion propulsion because no physical mass is expelled from the satellite.
For amateur satellites with omnidirectional antennas, the RF is emitted in all
directions and the force cancels out. Intelsat birds emit RF in tightly
focused beams so there will be a net force on the satellite, and if the
antenna is off axis from the satellite's center of gravity this force will
exert a torque which could cause the momentum wheels to spin up.
The uplink RF is minuscule (microwatts per square meter or less) but the lack
of uplink signals causes the linear transponders to have zero RF output (other
than noise), thus causing reduced off axis pressure on the satellite.
Dan Schultz N8FGV
>I couldn't help but notice that on this website
>http://www.intelsat.com/resources/galaxy-15/faqs.asp about "zombiesat"
>Galaxy 15, Intelsat figures that the lack of RF on thr transponder package
>since their loss of control earlier this year, will actually make it take
>longer to saturate it's momentum-wheel orientation stablizer system. This,
>compared to the manufacturer's original estimate of achieving the saturation
>condition beuing several months sooner having assumed normal full-load of RF
>on the transponders.
>My question is: How is this possible? Does the RF put acceleration-forces
>on the transmitting antenna of the satellite similar to ion propulsion, or
>does the uplink RF push on the receiving antenna? Is there some other
>mechanism that can electronically alter the forces acting on the body of the
>satellite based on the amount of RF power?
------------------------------
Message: 9
Date: Sun, 24 Oct 2010 23:52:24 -0400 (EDT)
From: Clint Bradford <clintbrad4d@xxxxxxxxx.xxx>
Subject: [amsat-bb] Why We Do What We Do - Part 19
To: amsat-bb@xxxxx.xxxx amsat-bb@xxxxx.xxx
Message-ID:
<24907522.1287978744463.JavaMail.root@xxxxxxxxxxxxx.xxx.xx.xxxxxxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
I just returned to the house after working a non-ham-radio-related event
since 6:30 this morning (a nonprofit equine rehab center that my wife and I
are board members). But I just HAVE to check email before crashing ...
There are some who say that promoting working the FM birds is a futile
effort. "Nothing comes of it," I have seen a few write.
Well, this email is from a person who worked JOTA last weekend. I was
supposed to - but instead was presenting my show at PACIFICON in San Ramon,
CA. But I traded notes with this person ... we compared pass times and freq
data ... I have been to their club three times the past three years to give
me presentation and demo. And we even worked each other: me from the parking
lot in San Ramon, and she with her Scouts in Victorville, CA.
>From her email just received ...
- - - - - - - - - - - - - - - - - - - - - - - - - - -
Hi Clint! Hope you and Karen's trip up north went well.
Well, you have started something.
I have gotten some local hams interested or re-interested
in working AMSAT. And I have been doing some more demos locally.
I am the low-tech version - with a compass, and recorder hung around
my neck and a clipboard with the sat passes info.
And since I can't hold the antenna up that long, I have it mounted on a
tripod. Don't laugh - it works!
And I am even tromping out at 10:00 pm (very bright last night).
And Bruce and I have subscribed to AMSAT mag and joined.
Thanks again, Clint.
73 - Christy KB6LTY
- - - - - - - - - - - - - - - - - - - - - - - - - -
NO, Christy, I am not "laughing." But there is a broad smile on my
face tonight. THANK YOU for joining AMSAT. And thank you for your
infectious enthusiasm.
Clint, K6LCS
http://www.work-sat.com
----------------------------------
Clint Bradford, K6LCS
http://www.clintbradford.com
------------------------------
Message: 10
Date: Mon, 25 Oct 2010 13:20:30 +0800
From: "Alan Kung" <alankung@xxxxxxx.xxx.xxx.xx>
Subject: [amsat-bb] HO-68 Schedule 24-31 Oct 2010
To: <amsat-bb@xxxxx.xxx>
Message-ID: <0F335DB5002540EFAAE7AD64C5F014EC@xxxxxxxxxxxxx>
Content-Type: text/plain; charset="gb2312"
UTC:
24 Oct 2010
================================
16:40...Turn On--CW/SSB
India, Africa, Middle East,
Europe,NA
17:25...Turn Off
18:30...Turn On--CW/SSB
Africa,Europe,Middle East,NA
19:15...Turn Off
19:55...Turn On--CW/SSB
Africa,Europe,Middle East,NA
20:40...Turn Off
22:35...Turn On--CW/SSB
South America,NA,North Asia
23:20...Turn Off
25 Oct 2010
================================
02:11...Turn On--CW/SSB
North Asia,East Asia,South Asia
02:26...Turn Off
13:10...Turn On--CW/SSB
NA,South America
13:55...Turn Off
16:25...Turn On--CW/SSB
India, Africa, Middle East,
Europe,NA
17:10...Turn Off
18:15...Turn On--CW/SSB
NA,East Asia,Oceania
19:00...Turn Off
26 Oct 2010
================================
00:05...Turn On--CW/SSB
NA,North Asia,East Asia,
Oceania
00:50...Turn Off
02:04...Turn On--CW/SSB
North Asia, East Asia,South Asia
02:19...Turn Off
10:15...Turn On--CW/SSB
Oceania,Asia,Europe
11:00...Turn Off
12:55...Turn On--CW/SSB
NA, South America
13:40...Turn Off
16:05...Turn On--CW/SSB
India,Middle East,Europe,NA
16:50...Turn Off
18:40...Turn On--CW/SSB
India,Middle East,Europe,NA
19:25...Turn Off
19:35...Turn On--CW/SSB
Africa,Europe,NA
20:15...Turn Off
27 Octp 2010
=================================
23:45...Turn On--CW/SSB
North Asia,East Asia,South Asia
Oceania
00:30...Turn Off
03:31...Turn On--CW/SSB
North Asia,East Asia,South Asia
03:45...Turn Off
14:25...Turn On--CW/SSB
Europe,NA,South America
15:10...Turn Off
17:40...Turn On--CW/SSB
India, Africa,Europe,NA
South America
18:25...Turn Off
19:25...Turn On--CW/SSB
Africa,Middle East,Europe,NA
20:10...Turn Off
20:55...Turn On--CW/SSB
Africa,Middle East,Europe,NA
21:40...Turn Off
28 Oct 2010
=================================
23:30...Turn On--CW/SSB
NA,North Asia,East Asia,Oceania
00:15...Turn Off
03:15...Turn On--CW/SSB
Asia,Oceania
03:27...Turn Off
14:10...Turn On--CW/SSB
Europe,NA,South America
14:55...Turn Off
17:20...Turn On--CW/SSB
Africa,India,Middle East
Europe,NA
18:05...Turn Off
19:10...Turn On--CW/SSB
Africa,Europe,NA
19:55...Turn Off
20:35...Turn On--CW/SSB
Africa,Europe,NA
21:20...Turn Off
29 Oct 2010
================================
23:15...Turn On--CW/SSB
Oceania,Asia,Europe,NA
00:00...Turn Off
02:59...Turn On--CW/SSB
North Asia,East Asia,South Asia
03:13...Turn Off
13:50...Turn On--CW/SSB
Europe, NA,South America
14:35...Turn Off
17:05...Turn On--CW/SSB
India,Africa,Europe,NA
17:50...Turn Off
18:55...Turn On--CW/SSB
India,Africa,Europe,NA
19:40...Turn Off
20:20...Turn On--CW/SSB
Africa,Europe,NA
21:05...Turn Off
22:55...Turn On--CW/SSB
South America,NA,North Asia
23:40...Turn Off
30 Oct 2010
================================
02:44...Turn On--FM
North Asia,East Asia,South Asia
03:00...Turn Off
13:35...Turn On--CW/SSB
Europe, NA,South America
14:20...Turn Off
16:45...Turn On--CW/SSB
Africa,Europe,NA
17:30...Turn Off
18:35...Turn On--CW/SSB
India,Africa,Europe,NA
19:20...Turn Off
20:00...Turn On--CW/SSB
Africa,Europe,NA
20:45...Turn Off
22:40...Turn On--CW/SSB
North Asia,East Asia,
South Asia,Oceania
23:25...Turn Off
31 Oct 2010
================================
02:26...Turn On--CW/SSB
North Asia,East Asia,South Asia
Oceania
02:42...Turn Off
13:15...Turn On--CW/SSB
Europe,NA,South America
14:00...Turn Off
73
Alan Kung, BA1DU
HO-68(XW-1) Project Manager
www.camsat.cn
------------------------------
Message: 11
Date: Sun, 24 Oct 2010 22:26:52 -0600
From: "Auke de Jong, VE6PWN" <sparkycivic@xxxx.xx>
Subject: [amsat-bb] Re: can RF change the orientation of a satellite?
To: "Daniel Schultz" <n8fgv@xxx.xxx>, <amsat-bb@xxxxx.xxx>
Cc: Rene Matthijssen <rene@xxxxxxxx.xxx>
Message-ID: <001401cb73fc$d9626c10$6800a8c0@xxxxxxx>
Content-Type: text/plain; charset="iso-8859-1"
Hi,
Thanks for the informative reply!
So it follows that this class of satellite with a maximum RF power output
of, say 3000W with all transponders fully loaded, that would add up to
significant forces! I'm also fairly certain that the primary transmitting
reflector hangs from the side of these satellites, opposite the receiving
reflector, so this is making sense. Until now, it was the last factor I
would have expected for prolonging the saga of Zombiesat!
Maybe they could send up some carriers at the passband edges of each
transponder while in-between orbital slots just to hasten the progress of
the saturation of the momentum-wheels?(just kidding) I'll be reading with
great interest, any news of how Galaxy 15 behaves after it has finally run
it's batteries down to cutoff, and if it can show what the fault actually
was, upon possible resumption of telemetry.
There could be a lesson in this for Amateur satellite designers and
builders, where fault-tolerance is definitely JUST AS important as
fault-avoidance - we always like our hardware to be useful to the last
drop(AO-7). Actually, Oscar 7 has now spent the bulk of her wakeful time in
a FAULTY state, while still very useful... legendary!
73
Auke
----- Original Message -----
From: "Daniel Schultz" <n8fgv@xxx.xxx>
To: <amsat-bb@xxxxx.xxx>
Sent: Sunday, October 24, 2010 7:15 PM
Subject: [amsat-bb] Re: can RF change the orientation of a satellite?
> It makes sense. Satellites are subject to solar radiation pressure from
> absorption of sunlight, they are also subject to radiation pressure from
> emission of RF radiation. The wavelength of the radiation does not enter
> into
> this calculation so the pressure from radio frequency radiation is the
> same as
> that of visible light radiation.
>
> Radiation pressure is the electromagnetic power flux density divided by
> the
> speed of light. If a 100 watt transponder emits RF in a narrow beam from a
> 1
> square meter antenna, the radiation pressure on the satellite will be 100
> watts / (1 square meter * 3E8 meters/sec) = 0.33 micropascals. The force
> on a
> 1 square meter antenna will thus be 0.33 micronewtons. This is not the
> same as
> ion propulsion because no physical mass is expelled from the satellite.
>
> For amateur satellites with omnidirectional antennas, the RF is emitted in
> all
> directions and the force cancels out. Intelsat birds emit RF in tightly
> focused beams so there will be a net force on the satellite, and if the
> antenna is off axis from the satellite's center of gravity this force will
> exert a torque which could cause the momentum wheels to spin up.
>
> The uplink RF is minuscule (microwatts per square meter or less) but the
> lack
> of uplink signals causes the linear transponders to have zero RF output
> (other
> than noise), thus causing reduced off axis pressure on the satellite.
>
> Dan Schultz N8FGV
>
>
>
>>I couldn't help but notice that on this website
>>http://www.intelsat.com/resources/galaxy-15/faqs.asp about "zombiesat"
>>Galaxy 15, Intelsat figures that the lack of RF on thr transponder package
>>since their loss of control earlier this year, will actually make it take
>>longer to saturate it's momentum-wheel orientation stablizer system.
>>This,
>>compared to the manufacturer's original estimate of achieving the
>>saturation
>>condition beuing several months sooner having assumed normal full-load of
>>RF
>>on the transponders.
>
>>My question is: How is this possible? Does the RF put acceleration-forces
>>on the transmitting antenna of the satellite similar to ion propulsion, or
>>does the uplink RF push on the receiving antenna? Is there some other
>>mechanism that can electronically alter the forces acting on the body of
>>the
>>satellite based on the amount of RF power?
>
>
> _______________________________________________
> 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
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
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>
------------------------------
Message: 12
Date: Mon, 25 Oct 2010 10:26:18 -0400
From: Martha <martha@xxxxx.xxx>
Subject: [amsat-bb] Re: Sept Financials
To: Dee <morsesat@xxxxxxxxx.xxx>
Cc: AMSAT BB <amsat-bb@xxxxx.xxx>, Keith Baker KB1SF/VA3KSF
<kb1sf@xxxxxxxxxxxxx.xxx>
Message-ID:
<AANLkTincw27Z5SK3xib0YcyBUstb6O3SRV_HMS=6sLUW@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=ISO-8859-1
On Sat, Oct 23, 2010 at 2:51 PM, Dee <morsesat@xxxxxxxxx.xxx> wrote:
> Nothing attached that I could read...
> Might be something I'd like to add to this week's ANS--Please resend with
> attachment.
> Dee
>
> -----Original Message-----
> From: amsat-bb-bounces@xxxxx.xxx [mailto:amsat-bb-bounces@xxxxx.xxxx On
> Behalf Of Martha
> Sent: Friday, October 22, 2010 3:46 PM
> To: AMSAT BB; Keith Baker KB1SF/VA3KSF; Martha
> Subject: [amsat-bb] Sept Financials
>
> Attached are the Sept 2010 Financial Reports
>
> --
> 73- Martha
>
>
>
--
73- Martha
------------------------------
Message: 13
Date: Mon, 25 Oct 2010 08:41:20 -0700 (PDT)
From: "Patrick STODDARD \(WD9EWK/VA7EWK\)" <amsat-bb@xxxxxx.xxx>
Subject: [amsat-bb] QSL cards mailed today, QSLs for DM30 activity on
Saturday, DM31?
To: amsat-bb@xxxxx.xxx
Message-ID: <900547.46502.qm@xxxxxxxx.xxxx.xxx.xxxxx.xxx>
Content-Type: text/plain; charset=us-ascii
Hi!
On my way to the office this morning, I dropped a few dozen envelopes
at the post office. I finished printing and writing out cards covering
my trips over the last 3 weekends (7-11 October for the AMSAT Symposium
and post-Symposium travel in/around Illinois, 16 October to a hamfest
in Tucson AZ followed by a quick trip to DM51/DM52, and Saturday's quick
trip to DM32/DM42 south of Phoenix) yesterday. They should start showing
up in mailboxes over the next few days.
On Saturday, there were a group of Mexican hams operating on HF and
satellites from grid DM30 south of the Arizona/Mexico border. I think
that most of the satellite operating from there was done by Alex
XE2BSS. If you worked XE2BSS and would like a QSL card, I am Alex's QSL
manager. Please send those requests to me. I heard three other calls
from that group on an SO-50 pass Saturday morning (David XE2DAK, Eliseo
XE2TPJ, and Uriel XE2VAS). I don't know how active these 3 were on FM
passes later in the day. Of those 3, I am also the QSL manager for
XE2VAS. If you need assistance in getting cards from any of these 4,
please feel free to e-mail me. I know all 4 of these guys, and may be
able to help with the QSL exchange.
Over the past 2+ years, I have operated from every grid that covers
the state of Arizona. For all of these grids except one, I have made
multiple trips to those grids. I have only made one trip to DM31 in
southern Arizona in September 2009, and have thought about making a
return trip now that the summertime heat is done for the year. Most
of DM31 is in Mexico, except for the northeast corner that reaches
into the Organ Pipe Cactus National Monument and the border town of
Lukeville AZ where I operated from last year. I would probably make a
return to Lukeville on a future trip. I don't currently have a Mexican
ham permit, and - even if I had a valid XE permit - I'm not interested
in crossing the Mexican border at that point. Since there are new
operators coming onto the satellites all the time, and some (many?) may
have missed my last trip down there. If there is any interest in another
trip down to DM31, please e-mail me directly.
73!
Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/
------------------------------
_______________________________________________
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 5, Issue 425
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