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To : SATDIG@WW
Today's Topics:
1. Re: AO-92 fading (Stefan Wagener)
2. Upcoming ARISS Contact Schedule as of 2018-03-28 08:00 UTC
(aj9n@???.????
3. Re: AO-92 fading (Mark L. Hammond)
4. Re: AO-92 fading (Stephen E. Belter)
----------------------------------------------------------------------
Message: 1
Date: Tue, 27 Mar 2018 21:38:51 -0500
From: Stefan Wagener <wageners@?????.???>
To: "Stephen E. Belter" <seb@??????.???>
Cc: Burns Fisher <burns@??????.??>, amsat-bb <amsat-bb@?????.???>,
Paul Stoetzer <n8hm@????.???>
Subject: Re: [amsat-bb] AO-92 fading
Message-ID:
<CAKu8kHDabVSxHSBAj4_C0HJqNDP6cJ=a2rzwpeg9yeipf=XTTA@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Thanks Steve,
Great point and well thought out. Now, let me ask you a question: After you
matched the downlink signal and position of your Arrow for maximum quieting
and best signal, what happens when you now change the position of your
arrow to look for best "uplink"? unless yo can keep the downlink position
steady you will not be able to check for the uplink.. as science tells me
one thing has to be constant for the other to be assessed...
All the best,
Stefan, VE4NSA
On Tue, Mar 27, 2018 at 9:27 PM, Stephen E. Belter <seb@??????.???> wrote:
> Stefan,
>
> You are correct that you only hear the downlink, but...
>
> From personal experience, including operating AO-85 and AO-91 today using
> a standard Arrow and an IC-821 (from a campground in EM87), I'm convinced
> that I can hear my uplink polarity mismatch.
>
> I first adjust the polarity of my antenna (by twisting my wrist) while
> searching for the strongest (maximum quieting) received signal. Then while
> pressing the PTT, I tweak the Arrow polarity while going for maximum
> quieting while listening to myself.
>
> The best sounding full-duplex signal is typically not at the same polarity
> as the best received signal from someone else on the satellite, but I've
> been able to get full quieting full-duplex. When operating full-duplex, I
> think I'm hearing the results of *both* the uplink and downlink polarity
> match.
>
> And that's how I 'differentiate between uplink "weakness" from downlink'
> weakness.
>
> 73, Steve N9IP
> --
> Steve Belter, seb@??????.???
>
>
> ?On 3/27/18, 10:06 PM, "AMSAT-BB on behalf of Stefan Wagener" <
> amsat-bb-bounces@?????.??? on behalf of wageners@?????.???> wrote:
>
> Hi Sterling,
>
> That would assume you have the ability to switch between linear uplink
> polarization (vertical and horizontal) and circular polarisation for
> uplink
> (right and left) and keep you downlink polarization on the same
> optimized path all the time, meaning you know in advance which way the
> downlink signal is the best to compensate for any uplink discrepancies.
> Good luck :-)
>
> But hanks, good thought!
>
> Stefan, VE4NSA
>
> On Tue, Mar 27, 2018 at 8:47 PM, Sterling Coffey <kawfey@?????.???>
> wrote:
>
> > If linear polarized, if you can keep your RX/downlink antenna still
> and
> > you can at least hear the satellite, and rotating your TX/uplink
> antenna
> > results in correlated signal level changes on the RX/downlink, then
> you've
> > isolated it to the uplink polarization variable.
> >
> > On Tue, Mar 27, 2018 at 8:44 PM, Stefan Wagener <wageners@?????.???>
> > wrote:
> >
> >> Thanks,
> >>
> >> Again, even in full duplex how do you distinguish between a
> non-matching
> >> uplink vs non-matching downlink? You only "hear" the downlink!
> >>
> >> 73, Stefan VE4NSA
> >>
> >> On Tue, Mar 27, 2018 at 8:38 PM, Sterling Coffey <kawfey@?????.???>
> >> wrote:
> >>
> >>> You can hear your own signal if you have a full duplex (two radio)
> >>> setup. However, it's still pretty hard to tell if you use a single
> antenna
> >>> (arrow, elk, etc) since you're changing the RX polarity while
> you're
> >>> changing the TX polarity too.
> >>>
> >>> On Tue, Mar 27, 2018 at 7:22 PM, Stefan Wagener <
> wageners@?????.???>
> >>> wrote:
> >>>
> >>>> One of the questions I have is why one would think that the uplink
> >>>> (polarization) is a problem since you only have the downlink to
> assess
> >>>> and
> >>>> how would you differentiate between uplink "weakness" from
> downlink
> >>>> since
> >>>> that is the only thing you hear. In addition, at least for
> uplink, you
> >>>> could "in principle" very quickly adjust with higher power... and
> no, I
> >>>> am
> >>>> NOT promoting crocodile behavior (big mouth little ears)
> >>>>
> >>>> Stefan, VE4NSA
> >>>>
> >>>> On Tue, Mar 27, 2018 at 2:26 PM, Burns Fisher <burns@??????.??>
> wrote:
> >>>>
> >>>> > If you have seen a model or picture of the Fox satellites, you
> may
> >>>> have
> >>>> > noticed that some of the solar panels seem to be mounted
> off-center.
> >>>> This
> >>>> > is intentional so that photons that reflect off the shiny side
> give
> >>>> it a
> >>>> > tiny off-center push that spins the bird to distribute the heat
> more
> >>>> > evenly. Thus it spins faster the more time it spends in the
> sun. In
> >>>> > addition, when it crosses the equator, it should flip over (-Z
> and +Z
> >>>> > reverse sides). This is because of the passive magnetic
> >>>> stabilization.
> >>>> > But I'm guessing that since it is spinning, that causes it to
> wobble.
> >>>> >
> >>>> > Why 92 seems worse I don't know--I can only assume it has
> something
> >>>> to do
> >>>> > with the orbit. That graph that Paul posted looks very
> different from
> >>>> > AO-85, for example.
> >>>> >
> >>>> > Some RF person can correct me, but I believe that the 70cm
> antenna
> >>>> only
> >>>> > uses the antenna that sticks out one side, while the 2m antenna
> >>>> actually
> >>>> > uses the antennas on both sides. Could that explain why the
> uplink
> >>>> has
> >>>> > more fading than the downlink? I don't know. Something to
> think
> >>>> about.
> >>>> >
> >>>> > 73,
> >>>> >
> >>>> > Burns WB1FJ
> >>>> > Fox-1 Flight Software
> >>>> >
> >>>> > On Tue, Mar 27, 2018 at 2:12 PM, Paul Stoetzer <n8hm@????.???>
> wrote:
> >>>> >
> >>>> > > All of the Fox-1 satellites seem to spin faster or slower
> depending
> >>>> on
> >>>> > > orbit illumination or other factors.
> >>>> > >
> >>>> > > For example, this is the +Z panel rotation on AO-92 since
> launch.
> >>>> > >
> >>>> > > https://imgur.com/a/uS8TB
> >>>> > >
> >>>> > > Someone more well-versed in these matters can comment further
> on
> >>>> what
> >>>> > > causes this, but it is definitely not an indication of the
> health
> >>>> > > status of the satellite.
> >>>> > >
> >>>> > > 73,
> >>>> > >
> >>>> > > Paul, N8HM
> >>>> > >
> >>>> > > On Tue, Mar 27, 2018 at 1:59 PM, Jean Marc Momple
> >>>> > > <jean.marc.momple@?????.???> wrote:
> >>>> > > > Dear All,
> >>>> > > >
> >>>> > > > I have been experimenting with AO-92 as from its launch.
> Some
> >>>> > > observations:
> >>>> > > >
> >>>> > > > 1) The fading on this bird seems to be high and quite
> >>>> unpredictable,
> >>>> > > requires a lot of changes of polarization to keep the Rx
> signal to
> >>>> an
> >>>> > > adequate level.
> >>>> > > >
> >>>> > > > 2) Seems that the fading is both on the U/V and L-mode, more
> >>>> seems to
> >>>> > me
> >>>> > > that the uplink is more affected.
> >>>> > > >
> >>>> > > > 3) Telemetry seems to be quite reliable with FoxTelem in all
> >>>> modes.
> >>>> > > >
> >>>> > > > Today, it was even worse losing the bird many times during
> the
> >>>> pass, it
> >>>> > > seems that it is degrading quite quickly, hope that this is
> not the
> >>>> case.
> >>>> > > >
> >>>> > > > Just to share my observation.
> >>>> > > >
> >>>> > > > 73
> >>>> > > >
> >>>> > > >
> >>>> > > > Jean Marc (3B8du)
> >>>> > > >
> >>>> > > >
> >>>> > > > _______________________________________________
> >>>> > > > Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum
> >>>> available
> >>>> > > > to all interested persons worldwide without requiring
> membership.
> >>>> > > Opinions expressed
> >>>> > > > are solely those of the author, and do not reflect the
> official
> >>>> views
> >>>> > of
> >>>> > > AMSAT-NA.
> >>>> > > > Not an AMSAT-NA member? Join now to support the amateur
> satellite
> >>>> > > program!
> >>>> > > > Subscription settings: http://www.amsat.org/mailman/l
> >>>> istinfo/amsat-bb
> >>>> > > _______________________________________________
> >>>> > > Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum
> >>>> available
> >>>> > > to all interested persons worldwide without requiring
> membership.
> >>>> > Opinions
> >>>> > > expressed
> >>>> > > are solely those of the author, and do not reflect the
> official
> >>>> views of
> >>>> > > AMSAT-NA.
> >>>> > > Not an AMSAT-NA member? Join now to support the amateur
> satellite
> >>>> > program!
> >>>> > > Subscription settings: http://www.amsat.org/mailman/l
> >>>> istinfo/amsat-bb
> >>>> > >
> >>>> > _______________________________________________
> >>>> > Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum
> available
> >>>> > to all interested persons worldwide without requiring
> membership.
> >>>> Opinions
> >>>> > expressed
> >>>> > are solely those of the author, and do not reflect the official
> views
> >>>> of
> >>>> > AMSAT-NA.
> >>>> > Not an AMSAT-NA member? Join now to support the amateur
> satellite
> >>>> program!
> >>>> > Subscription settings: http://www.amsat.org/mailman/
> listinfo/amsat-bb
> >>>> >
> >>>> _______________________________________________
> >>>> Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum
> available
> >>>> to all interested persons worldwide without requiring membership.
> >>>> Opinions expressed
> >>>> are solely those of the author, and do not reflect the official
> views
> >>>> of AMSAT-NA.
> >>>> Not an AMSAT-NA member? Join now to support the amateur satellite
> >>>> program!
> >>>> Subscription settings: http://www.amsat.org/mailman/
> listinfo/amsat-bb
> >>>>
> >>>
> >>>
> >>
> >
> _______________________________________________
> Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership.
> Opinions expressed
> are solely those of the author, and do not reflect the official views
> of AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite
> program!
> Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
>
>
>
------------------------------
Message: 2
Date: Wed, 28 Mar 2018 03:12:16 -0400
From: aj9n@???.???
To: amsat-bb@?????.???
Subject: [amsat-bb] Upcoming ARISS Contact Schedule as of 2018-03-28
08:00 UTC
Message-ID: <1626b7338e7-1dc5-6b60@?????????????.???.???????.???>
Content-Type: text/plain; charset=utf-8
Upcoming ARISS Contact Schedule as of 2018-03-28 08:00 UTC
Quick list of scheduled contacts and events:
?
Freeport Public Schools, Freeport, NY, telebridge via IK1SLD
The ISS callsign is presently scheduled to be OR4ISS
The scheduled astronaut is Scott Tingle KG5NZA
Contact was successful: Tue 2018-03-27 17:41:04 UTC 24 deg ?(***)
?
Valday, Russia, direct via TBD (***)
The ISS callsign is presently scheduled to be RS?ISS (***)
The scheduled astronaut is Oleg Artemyev (***)
Contact is a go for 2018-04-04 TBD UTC (***)
?
?
Vologda, Russia, direct via TBD (***)
The ISS callsign is presently scheduled to be RS?ISS (***)
The scheduled astronaut is Oleg Artemyev (***)
Contact is a go for 2018-04-10 13:37 UTC (***)
?
Exp. 55 on orbit (***)
Welcome aboard! (***)
Drew Feustel
Oleg Artemyev
Ricky Arnold KE5DAU
******************************************************************************
International Space Station Astronauts are Calling CQ Students? (corrected)?
(***)
?????????????? ARISS-US program education proposal deadline is April 30, 2018
?
March 15, 2018:? The Amateur Radio on the International Space Station
(ARISS) program is seeking proposals from US schools, museums, science
centers and community youth organizations (working individually or together)
to host radio contacts with an orbiting crew member aboard the International
Space Station (ISS) between January 1 and June 30, 2019.
?
Each year, ARISS provides tens of thousands of students with opportunities
to learn about space technologies and communications through the exploration
of Amateur Radio.? The program provides learning opportunities by connecting
students to astronauts aboard the International Space Station (ISS) through
a partnership between NASA, the Radio Amateur Satellite Corporation, the
American Radio Relay League, and other Amateur Radio organizations and
worldwide space agencies. The program?s goal is to inspire students to
pursue interests and careers in science, technology, engineering and
mathematics (STEM) and Amateur Radio. A ham recently said, ?ARISS shows how
Amateur Radio is the most unique hobby/service there is.?
?
Educators overwhelmingly report that student participation in the ARISS
program stimulates interest in STEM subjects and in STEM careers. One
educator wrote, ?It exceeded our expectations--it created a great interest
in both amateur radio and in space exploration. Our kids are completely
inspired!? Ninety-two percent of educators who have participated in the
program have indicated that ARISS provided ideas for encouraging student
exploration and participation. An educator even joined the ham ranks,
saying, ?This chance for our school?s ARISS contact helped me see the great
value of the ham world.? I just passed my Technician License this weekend
and have already signed up to take a General class.?? ?
ARISS is looking for organizations that will draw large numbers of
participants and integrate the contact into a well-developed, exciting
education plan. Students can learn about satellite communications, wireless
technology, science research conducted on the ISS, radio science, and any
related STEM subject. Students learn to use Amateur Radio to talk directly
to an astronaut and ask their STEM-related questions. ARISS will help
educational organizations locate Amateur Radio groups who can assist with
equipment for this once-in-a-lifetime opportunity for students.
The proposal deadline for 2019 contacts is April 30, 2018. Proposal webinars
for guidance and getting questions answers will be offered March 29, 2018,
at 7 p.m. EDT and April 16, 2018, at 4 p.m. EDT. Advance registration is
necessary. To sign up, go to
https://ariss-proposal-webinar-spring-2018.eventbrite.com
For more details such as expectations, proposal guidelines and the proposal
form, visit: http://www.ariss.org/hosting-an-ariss-contact-in-the-us.html
?
******************************************************************************
ARISS is always glad to receive listener reports for the above contacts.?
ARISS thanks everyone in advance for their assistance.? Feel free to send
your reports to aj9n@?????.??? or aj9n@???.???.
?
Listen for the ISS on the downlink of 145.8? MHz.
?
******************************************************************************
*
?
All ARISS contacts are made via the Kenwood radio unless otherwise noted.
?
******************************************************************************
*
Several?of you have sent me emails asking about the RAC ARISS website and
not being able?to get in.? That has now been changed to?
http://www.ariss.org/
Note that there are links to other ARISS websites from this?site.
****************************************************************************
Looking?for something new to do?? How about receiving DATV from the ISS???
If interested, then please go to the ARISS-EU website for complete?
details.? Look for the buttons indicating Ham?Video.? ? ? ? ? ? ? ? ? ? ? ?
? ?
? ? ? ? ? ? ? ? ? ? ?
http://www.ariss-eu.org/? ?
?
If you need some assistance, ARISS mentor Kerry N6IZW, might be able to
provide some insight.? Contact Kerry at kbanke@?????????.???
****************************************************************************
ARISS congratulations the following mentors who have now mentored over 100
schools:?
Francesco IK?WGF with 132
Satoshi 7M3TJZ with 128
Gaston ON4WF with 123
Sergey RV3DR with 102
****************************************************************************
The?webpages listed below were all reviewed for accuracy.? Out of date
webpages?were removed and new ones have been added.? If there are additional
ARISS?websites I need to know about, please let me know.
Note, all times?are approximate.? It is recommended that you do your own
orbital prediction?or start listening about 10 minutes before the listed
time.
All dates and?times listed follow International Standard ISO 8601 date and
time format? YYYY-MM-DD HH:MM:SS
The complete schedule page has been updated as of?2018-03-28 08:30 UTC.? (***)
Here you will find a listing of all scheduled?school contacts, and
questions, other ISS related websites, IRLP and?Echolink websites, and
instructions for any contact that may be streamed?live.??
http://www.amsat.org/amsat/ariss/news/arissnews.rtf
http://www.amsat.org/amsat/ariss/news/arissnews.txt
Total number?of ARISS ISS to earth school events is 1217. (***)
Each school counts as 1?event.
Total number of ARISS ISS to earth school contacts is 1166. (***)
Each contact may have multiple schools sharing the same time slot.
Total number of ARISS supported terrestrial contacts is?47.
A complete year by year breakdown of the contacts may be found in the
file.
http://www.amsat.org/amsat/ariss/news/arissnews.rtf
Please?feel free to contact me if more detailed statistics are needed.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
The?following US states and entities have never had an ARISS contact:
Arkansas,?Delaware, South Dakota, Wyoming, American?Samoa, Guam, Northern
Marianas Islands, and the Virgin Islands.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
QSL?information may be found at:??
http://www.ariss.org/qsl-cards.html?
ISS callsigns:? DP?ISS, IR?ISS, NA1SS, OR4ISS,?RS?ISS
****************************************************************************
The successful school list has been updated as of 2018-03-28 08:00 UTC. (***)
http://www.amsat.org/amsat/ariss/news/Successful_ARISS_schools.rtf
Frequency? chart for packet, voice, and crossband repeater modes showing
Doppler? correction? as of 2005-07-29 04:00 UTC
http://www.amsat.org/amsat/ariss/news/ISS_frequencies_and_Doppler_correction
.rtf
Listing?of ARISS related magazine articles as of 2006-07-10 03:30 UTC.
http://www.amsat.org/amsat/ariss/news/ARISS_magazine_articles.rtf
Check out the Zoho reports of the ARISS?contacts
https://reports.zoho.com/ZDBDataSheetView.cc?DBID=412218000000020415
****************************************************************************
Exp. 54 on orbit
Scott Tingle KG5NZA
Norishige Kanai
Alexander Skvortsov
?
Exp. 55 on orbit (***)
Welcome aboard! (***)
Drew Feustel
Oleg Artemyev
Ricky Arnold KE5DAU
****************************************************************************
73,
Charlie?Sufana AJ9N
One of the ARISS operation team mentors
?
?
?
?
?
?
?
?
?
?
?
?
?
------------------------------
Message: 3
Date: Wed, 28 Mar 2018 07:44:26 -0400
From: "Mark L. Hammond" <marklhammond@?????.???>
To: Stefan Wagener <wageners@?????.???>, Amsat - BBs
<amsat-bb@?????.???>
Subject: Re: [amsat-bb] AO-92 fading
Message-ID:
<CAPRXzyp4K2Yawd0_097DV1DgOvW5apBdAxsJAoxGNcENqLLj2Q@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Stefan,
The reason I suggested using telemetry is because there is no uplink
variable to deal with. I thought the original issue was about "fading" and
why it happens. One can look at only the downlink, if interested. This
would allow somebody to study downlink fading. Of course, it doesn't touch
the uplink side of the issue...but that was rather my point.
Mark N8MH
On Tue, Mar 27, 2018 at 10:38 PM, Stefan Wagener <wageners@?????.???> wrote:
> Thanks Steve,
>
> Great point and well thought out. Now, let me ask you a question: After you
> matched the downlink signal and position of your Arrow for maximum quieting
> and best signal, what happens when you now change the position of your
> arrow to look for best "uplink"? unless yo can keep the downlink position
> steady you will not be able to check for the uplink.. as science tells me
> one thing has to be constant for the other to be assessed...
>
> All the best,
>
> Stefan, VE4NSA
>
>
>
> On Tue, Mar 27, 2018 at 9:27 PM, Stephen E. Belter <seb@??????.???> wrote:
>
> > Stefan,
> >
> > You are correct that you only hear the downlink, but...
> >
> > From personal experience, including operating AO-85 and AO-91 today using
> > a standard Arrow and an IC-821 (from a campground in EM87), I'm convinced
> > that I can hear my uplink polarity mismatch.
> >
> > I first adjust the polarity of my antenna (by twisting my wrist) while
> > searching for the strongest (maximum quieting) received signal. Then
> while
> > pressing the PTT, I tweak the Arrow polarity while going for maximum
> > quieting while listening to myself.
> >
> > The best sounding full-duplex signal is typically not at the same
> polarity
> > as the best received signal from someone else on the satellite, but I've
> > been able to get full quieting full-duplex. When operating full-duplex,
> I
> > think I'm hearing the results of *both* the uplink and downlink polarity
> > match.
> >
> > And that's how I 'differentiate between uplink "weakness" from downlink'
> > weakness.
> >
> > 73, Steve N9IP
> > --
> > Steve Belter, seb@??????.???
> >
> >
> > ?On 3/27/18, 10:06 PM, "AMSAT-BB on behalf of Stefan Wagener" <
> > amsat-bb-bounces@?????.??? on behalf of wageners@?????.???> wrote:
> >
> > Hi Sterling,
> >
> > That would assume you have the ability to switch between linear
> uplink
> > polarization (vertical and horizontal) and circular polarisation for
> > uplink
> > (right and left) and keep you downlink polarization on the same
> > optimized path all the time, meaning you know in advance which way
> the
> > downlink signal is the best to compensate for any uplink
> discrepancies.
> > Good luck :-)
> >
> > But hanks, good thought!
> >
> > Stefan, VE4NSA
> >
> > On Tue, Mar 27, 2018 at 8:47 PM, Sterling Coffey <kawfey@?????.???>
> > wrote:
> >
> > > If linear polarized, if you can keep your RX/downlink antenna still
> > and
> > > you can at least hear the satellite, and rotating your TX/uplink
> > antenna
> > > results in correlated signal level changes on the RX/downlink, then
> > you've
> > > isolated it to the uplink polarization variable.
> > >
> > > On Tue, Mar 27, 2018 at 8:44 PM, Stefan Wagener <
> wageners@?????.???>
> > > wrote:
> > >
> > >> Thanks,
> > >>
> > >> Again, even in full duplex how do you distinguish between a
> > non-matching
> > >> uplink vs non-matching downlink? You only "hear" the downlink!
> > >>
> > >> 73, Stefan VE4NSA
> > >>
> > >> On Tue, Mar 27, 2018 at 8:38 PM, Sterling Coffey <
> kawfey@?????.???>
> > >> wrote:
> > >>
> > >>> You can hear your own signal if you have a full duplex (two
> radio)
> > >>> setup. However, it's still pretty hard to tell if you use a
> single
> > antenna
> > >>> (arrow, elk, etc) since you're changing the RX polarity while
> > you're
> > >>> changing the TX polarity too.
> > >>>
> > >>> On Tue, Mar 27, 2018 at 7:22 PM, Stefan Wagener <
> > wageners@?????.???>
> > >>> wrote:
> > >>>
> > >>>> One of the questions I have is why one would think that the
> uplink
> > >>>> (polarization) is a problem since you only have the downlink to
> > assess
> > >>>> and
> > >>>> how would you differentiate between uplink "weakness" from
> > downlink
> > >>>> since
> > >>>> that is the only thing you hear. In addition, at least for
> > uplink, you
> > >>>> could "in principle" very quickly adjust with higher power...
> and
> > no, I
> > >>>> am
> > >>>> NOT promoting crocodile behavior (big mouth little ears)
> > >>>>
> > >>>> Stefan, VE4NSA
> > >>>>
> > >>>> On Tue, Mar 27, 2018 at 2:26 PM, Burns Fisher <burns@??????.??>
> > wrote:
> > >>>>
> > >>>> > If you have seen a model or picture of the Fox satellites, you
> > may
> > >>>> have
> > >>>> > noticed that some of the solar panels seem to be mounted
> > off-center.
> > >>>> This
> > >>>> > is intentional so that photons that reflect off the shiny side
> > give
> > >>>> it a
> > >>>> > tiny off-center push that spins the bird to distribute the
> heat
> > more
> > >>>> > evenly. Thus it spins faster the more time it spends in the
> > sun. In
> > >>>> > addition, when it crosses the equator, it should flip over (-Z
> > and +Z
> > >>>> > reverse sides). This is because of the passive magnetic
> > >>>> stabilization.
> > >>>> > But I'm guessing that since it is spinning, that causes it to
> > wobble.
> > >>>> >
> > >>>> > Why 92 seems worse I don't know--I can only assume it has
> > something
> > >>>> to do
> > >>>> > with the orbit. That graph that Paul posted looks very
> > different from
> > >>>> > AO-85, for example.
> > >>>> >
> > >>>> > Some RF person can correct me, but I believe that the 70cm
> > antenna
> > >>>> only
> > >>>> > uses the antenna that sticks out one side, while the 2m
> antenna
> > >>>> actually
> > >>>> > uses the antennas on both sides. Could that explain why the
> > uplink
> > >>>> has
> > >>>> > more fading than the downlink? I don't know. Something to
> > think
> > >>>> about.
> > >>>> >
> > >>>> > 73,
> > >>>> >
> > >>>> > Burns WB1FJ
> > >>>> > Fox-1 Flight Software
> > >>>> >
> > >>>> > On Tue, Mar 27, 2018 at 2:12 PM, Paul Stoetzer <n8hm@????.???
> >
> > wrote:
> > >>>> >
> > >>>> > > All of the Fox-1 satellites seem to spin faster or slower
> > depending
> > >>>> on
> > >>>> > > orbit illumination or other factors.
> > >>>> > >
> > >>>> > > For example, this is the +Z panel rotation on AO-92 since
> > launch.
> > >>>> > >
> > >>>> > > https://imgur.com/a/uS8TB
> > >>>> > >
> > >>>> > > Someone more well-versed in these matters can comment
> further
> > on
> > >>>> what
> > >>>> > > causes this, but it is definitely not an indication of the
> > health
> > >>>> > > status of the satellite.
> > >>>> > >
> > >>>> > > 73,
> > >>>> > >
> > >>>> > > Paul, N8HM
> > >>>> > >
> > >>>> > > On Tue, Mar 27, 2018 at 1:59 PM, Jean Marc Momple
> > >>>> > > <jean.marc.momple@?????.???> wrote:
> > >>>> > > > Dear All,
> > >>>> > > >
> > >>>> > > > I have been experimenting with AO-92 as from its launch.
> > Some
> > >>>> > > observations:
> > >>>> > > >
> > >>>> > > > 1) The fading on this bird seems to be high and quite
> > >>>> unpredictable,
> > >>>> > > requires a lot of changes of polarization to keep the Rx
> > signal to
> > >>>> an
> > >>>> > > adequate level.
> > >>>> > > >
> > >>>> > > > 2) Seems that the fading is both on the U/V and L-mode,
> more
> > >>>> seems to
> > >>>> > me
> > >>>> > > that the uplink is more affected.
> > >>>> > > >
> > >>>> > > > 3) Telemetry seems to be quite reliable with FoxTelem in
> all
> > >>>> modes.
> > >>>> > > >
> > >>>> > > > Today, it was even worse losing the bird many times during
> > the
> > >>>> pass, it
> > >>>> > > seems that it is degrading quite quickly, hope that this is
> > not the
> > >>>> case.
> > >>>> > > >
> > >>>> > > > Just to share my observation.
> > >>>> > > >
> > >>>> > > > 73
> > >>>> > > >
> > >>>> > > >
> > >>>> > > > Jean Marc (3B8du)
> > >>>> > > >
> > >>>> > > >
> > >>>> > > > _______________________________________________
> > >>>> > > > Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open
> forum
> > >>>> available
> > >>>> > > > to all interested persons worldwide without requiring
> > membership.
> > >>>> > > Opinions expressed
> > >>>> > > > are solely those of the author, and do not reflect the
> > official
> > >>>> views
> > >>>> > of
> > >>>> > > AMSAT-NA.
> > >>>> > > > Not an AMSAT-NA member? Join now to support the amateur
> > satellite
> > >>>> > > program!
> > >>>> > > > Subscription settings: http://www.amsat.org/mailman/l
> > >>>> istinfo/amsat-bb
> > >>>> > > _______________________________________________
> > >>>> > > Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum
> > >>>> available
> > >>>> > > to all interested persons worldwide without requiring
> > membership.
> > >>>> > Opinions
> > >>>> > > expressed
> > >>>> > > are solely those of the author, and do not reflect the
> > official
> > >>>> views of
> > >>>> > > AMSAT-NA.
> > >>>> > > Not an AMSAT-NA member? Join now to support the amateur
> > satellite
> > >>>> > program!
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> > >>>> istinfo/amsat-bb
> > >>>> > >
> > >>>> > _______________________________________________
> > >>>> > Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum
> > available
> > >>>> > to all interested persons worldwide without requiring
> > membership.
> > >>>> Opinions
> > >>>> > expressed
> > >>>> > are solely those of the author, and do not reflect the
> official
> > views
> > >>>> of
> > >>>> > AMSAT-NA.
> > >>>> > Not an AMSAT-NA member? Join now to support the amateur
> > satellite
> > >>>> program!
> > >>>> > Subscription settings: http://www.amsat.org/mailman/
> > listinfo/amsat-bb
> > >>>> >
> > >>>> _______________________________________________
> > >>>> Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum
> > available
> > >>>> to all interested persons worldwide without requiring
> membership.
> > >>>> Opinions expressed
> > >>>> are solely those of the author, and do not reflect the official
> > views
> > >>>> of AMSAT-NA.
> > >>>> Not an AMSAT-NA member? Join now to support the amateur
> satellite
> > >>>> program!
> > >>>> Subscription settings: http://www.amsat.org/mailman/
> > listinfo/amsat-bb
> > >>>>
> > >>>
> > >>>
> > >>
> > >
> > _______________________________________________
> > Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum
> available
> > to all interested persons worldwide without requiring membership.
> > Opinions expressed
> > are solely those of the author, and do not reflect the official views
> > of AMSAT-NA.
> > Not an AMSAT-NA member? Join now to support the amateur satellite
> > program!
> > Subscription settings: http://www.amsat.org/mailman/
> listinfo/amsat-bb
> >
> >
> >
> _______________________________________________
> Sent via AMSAT-BB@?????.???. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
> expressed
> are solely those of the author, and do not reflect the official views of
> AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
>
--
Mark L. Hammond [N8MH]
------------------------------
Message: 4
Date: Wed, 28 Mar 2018 12:20:35 +0000
From: "Stephen E. Belter" <seb@??????.???>
To: Stefan Wagener <wageners@?????.???>
Cc: Burns Fisher <burns@??????.??>, amsat-bb <amsat-bb@?????.???>,
Paul Stoetzer <n8hm@????.???>
Subject: Re: [amsat-bb] AO-92 fading
Message-ID: <F3037B70-1632-472D-AAAD-3DF504DB3823@??????.???>
Content-Type: text/plain; charset="utf-8"
Stefan,
My observations, not backed by science or a good understanding of antenna
theory, is that the polarity peaks (best reception) are fairly broad, while
the nulls are pretty sharp. (I studied electrical engineering, but I was
never good at field theory.)
As a result, I can twist the Arrow a little off of the best reception point
without taking too much of a received signal strength hit, while allowing me
to move the transmit polarity away from a null. At least that is what seems
happen when I?m operating portable.
73, Steve N9IP
--
Steve Belter, seb@??????.???
From: Stefan Wagener <wageners@?????.???>
Date: Tuesday, March 27, 2018 at 10:39 PM
To: "Stephen E. Belter" <seb@??????.???>
Cc: Sterling Coffey <kawfey@?????.???>, Paul Stoetzer <n8hm@????.???>,
AMSAT-BB <amsat-bb@?????.???>, Burns Fisher <burns@??????.??>
Subject: Re: [amsat-bb] AO-92 fading
Thanks Steve,
Great point and well thought out. Now, let me ask you a question: After you
matched the downlink signal and position of your Arrow for maximum quieting
and best signal, what happens when you now change the position of your arrow
to look for best "uplink"? unless yo can keep the downlink position steady
you will not be able to check for the uplink.. as science tells me one thing
has to be constant for the other to be assessed...
All the best,
Stefan, VE4NSA
On Tue, Mar 27, 2018 at 9:27 PM, Stephen E. Belter
<seb@??????.???<??????????@??????.???>> wrote:
Stefan,
You are correct that you only hear the downlink, but...
From personal experience, including operating AO-85 and AO-91 today using a
standard Arrow and an IC-821 (from a campground in EM87), I'm convinced that
I can hear my uplink polarity mismatch.
I first adjust the polarity of my antenna (by twisting my wrist) while
searching for the strongest (maximum quieting) received signal. Then while
pressing the PTT, I tweak the Arrow polarity while going for maximum
quieting while listening to myself.
The best sounding full-duplex signal is typically not at the same polarity
as the best received signal from someone else on the satellite, but I've
been able to get full quieting full-duplex. When operating full-duplex, I
think I'm hearing the results of *both* the uplink and downlink polarity
match.
And that's how I 'differentiate between uplink "weakness" from downlink'
weakness.
73, Steve N9IP
--
Steve Belter, seb@??????.???<??????????@??????.???>
On 3/27/18, 10:06 PM, "AMSAT-BB on behalf of Stefan Wagener"
<amsat-bb-bounces@?????.???<???????????????????????@?????.???> on behalf of
wageners@?????.???<???????????????@?????.???>> wrote:
Hi Sterling,
That would assume you have the ability to switch between linear uplink
polarization (vertical and horizontal) and circular polarisation for
uplink
(right and left) and keep you downlink polarization on the same
optimized path all the time, meaning you know in advance which way the
downlink signal is the best to compensate for any uplink discrepancies.
Good luck :-)
But hanks, good thought!
Stefan, VE4NSA
On Tue, Mar 27, 2018 at 8:47 PM, Sterling Coffey
<kawfey@?????.???<?????????????@?????.???>> wrote:
> If linear polarized, if you can keep your RX/downlink antenna still and
> you can at least hear the satellite, and rotating your TX/uplink antenna
> results in correlated signal level changes on the RX/downlink, then
you've
> isolated it to the uplink polarization variable.
>
> On Tue, Mar 27, 2018 at 8:44 PM, Stefan Wagener
<wageners@?????.???<???????????????@?????.???>>
> wrote:
>
>> Thanks,
>>
>> Again, even in full duplex how do you distinguish between a
non-matching
>> uplink vs non-matching downlink? You only "hear" the downlink!
>>
>> 73, Stefan VE4NSA
>>
>> On Tue, Mar 27, 2018 at 8:38 PM, Sterling Coffey
<kawfey@?????.???<?????????????@?????.???>>
>> wrote:
>>
>>> You can hear your own signal if you have a full duplex (two radio)
>>> setup. However, it's still pretty hard to tell if you use a single
antenna
>>> (arrow, elk, etc) since you're changing the RX polarity while you're
>>> changing the TX polarity too.
>>>
>>> On Tue, Mar 27, 2018 at 7:22 PM, Stefan Wagener
<wageners@?????.???<???????????????@?????.???>>
>>> wrote:
>>>
>>>> One of the questions I have is why one would think that the uplink
>>>> (polarization) is a problem since you only have the downlink to
assess
>>>> and
>>>> how would you differentiate between uplink "weakness" from downlink
>>>> since
>>>> that is the only thing you hear. In addition, at least for uplink,
you
>>>> could "in principle" very quickly adjust with higher power... and
no, I
>>>> am
>>>> NOT promoting crocodile behavior (big mouth little ears)
>>>>
>>>> Stefan, VE4NSA
>>>>
>>>> On Tue, Mar 27, 2018 at 2:26 PM, Burns Fisher <burns@??????.??>
wrote:
>>>>
>>>> > If you have seen a model or picture of the Fox satellites, you may
>>>> have
>>>> > noticed that some of the solar panels seem to be mounted
off-center.
>>>> This
>>>> > is intentional so that photons that reflect off the shiny side give
>>>> it a
>>>> > tiny off-center push that spins the bird to distribute the heat
more
>>>> > evenly. Thus it spins faster the more time it spends in the sun.
In
>>>> > addition, when it crosses the equator, it should flip over (-Z
and +Z
>>>> > reverse sides). This is because of the passive magnetic
>>>> stabilization.
>>>> > But I'm guessing that since it is spinning, that causes it to
wobble.
>>>> >
>>>> > Why 92 seems worse I don't know--I can only assume it has something
>>>> to do
>>>> > with the orbit. That graph that Paul posted looks very different
from
>>>> > AO-85, for example.
>>>> >
>>>> > Some RF person can correct me, but I believe that the 70cm antenna
>>>> only
>>>> > uses the antenna that sticks out one side, while the 2m antenna
>>>> actually
>>>> > uses the antennas on both sides. Could that explain why the uplink
>>>> has
>>>> > more fading than the downlink? I don't know. Something to think
>>>> about.
>>>> >
>>>> > 73,
>>>> >
>>>> > Burns WB1FJ
>>>> > Fox-1 Flight Software
>>>> >
>>>> > On Tue, Mar 27, 2018 at 2:12 PM, Paul Stoetzer
<n8hm@????.???<???????????@????.???>> wrote:
>>>> >
>>>> > > All of the Fox-1 satellites seem to spin faster or slower
depending
>>>> on
>>>> > > orbit illumination or other factors.
>>>> > >
>>>> > > For example, this is the +Z panel rotation on AO-92 since launch.
>>>> > >
>>>> > > https://imgur.com/a/uS8TB
>>>> > >
>>>> > > Someone more well-versed in these matters can comment further on
>>>> what
>>>> > > causes this, but it is definitely not an indication of the health
>>>> > > status of the satellite.
>>>> > >
>>>> > > 73,
>>>> > >
>>>> > > Paul, N8HM
>>>> > >
>>>> > > On Tue, Mar 27, 2018 at 1:59 PM, Jean Marc Momple
>>>> > > <jean.marc.momple@?????.???<???????????.????.??????@?????.???>>
wrote:
>>>> > > > Dear All,
>>>> > > >
>>>> > > > I have been experimenting with AO-92 as from its launch. Some
>>>> > > observations:
>>>> > > >
>>>> > > > 1) The fading on this bird seems to be high and quite
>>>> unpredictable,
>>>> > > requires a lot of changes of polarization to keep the Rx
signal to
>>>> an
>>>> > > adequate level.
>>>> > > >
>>>> > > > 2) Seems that the fading is both on the U/V and L-mode, more
>>>> seems to
>>>> > me
>>>> > > that the uplink is more affected.
>>>> > > >
>>>> > > > 3) Telemetry seems to be quite reliable with FoxTelem in all
>>>> modes.
>>>> > > >
>>>> > > > Today, it was even worse losing the bird many times during the
>>>> pass, it
>>>> > > seems that it is degrading quite quickly, hope that this is not
the
>>>> case.
>>>> > > >
>>>> > > > Just to share my observation.
>>>> > > >
>>>> > > > 73
>>>> > > >
>>>> > > >
>>>> > > > Jean Marc (3B8du)
>>>> > > >
>>>> > > >
>>>> > > > _______________________________________________
>>>> > > > Sent via AMSAT-BB@?????.???<???????????????@?????.???>.
AMSAT-NA makes this open forum
>>>> available
>>>> > > > to all interested persons worldwide without requiring
membership.
>>>> > > Opinions expressed
>>>> > > > are solely those of the author, and do not reflect the official
>>>> views
>>>> > of
>>>> > > AMSAT-NA.
>>>> > > > Not an AMSAT-NA member? Join now to support the amateur
satellite
>>>> > > program!
>>>> > > > Subscription settings: http://www.amsat.org/mailman/l
>>>> istinfo/amsat-bb
>>>> > > _______________________________________________
>>>> > > Sent via AMSAT-BB@?????.???<???????????????@?????.???>.
AMSAT-NA makes this open forum
>>>> available
>>>> > > to all interested persons worldwide without requiring membership.
>>>> > Opinions
>>>> > > expressed
>>>> > > are solely those of the author, and do not reflect the official
>>>> views of
>>>> > > AMSAT-NA.
>>>> > > Not an AMSAT-NA member? Join now to support the amateur satellite
>>>> > program!
>>>> > > Subscription settings: http://www.amsat.org/mailman/l
>>>> istinfo/amsat-bb
>>>> > >
>>>> > _______________________________________________
>>>> > Sent via AMSAT-BB@?????.???<???????????????@?????.???>. AMSAT-NA
makes this open forum available
>>>> > to all interested persons worldwide without requiring membership.
>>>> Opinions
>>>> > expressed
>>>> > are solely those of the author, and do not reflect the official
views
>>>> of
>>>> > AMSAT-NA.
>>>> > Not an AMSAT-NA member? Join now to support the amateur satellite
>>>> program!
>>>> > Subscription settings:
http://www.amsat.org/mailman/listinfo/amsat-bb
>>>> >
>>>> _______________________________________________
>>>> Sent via AMSAT-BB@?????.???<???????????????@?????.???>. AMSAT-NA
makes this open forum available
>>>> to all interested persons worldwide without requiring membership.
>>>> Opinions expressed
>>>> are solely those of the author, and do not reflect the official views
>>>> of AMSAT-NA.
>>>> Not an AMSAT-NA member? Join now to support the amateur satellite
>>>> program!
>>>> Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
>>>>
>>>
>>>
>>
>
_______________________________________________
Sent via AMSAT-BB@?????.???<???????????????@?????.???>. AMSAT-NA makes
this open forum available
to all interested persons worldwide without requiring membership.
Opinions expressed
are solely those of the author, and do not reflect the official views of
AMSAT-NA.
Not an AMSAT-NA member? Join now to support the amateur satellite program!
Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Subject: Digest Footer
_______________________________________________
Sent via amsat-bb@?????.???.
AMSAT-NA makes this open forum available to all interested persons worldwide
without requiring membership. Opinions expressed
are solely those of the author, and do not reflect the official views of
AMSAT-NA.
Not an AMSAT member? Join now to support the amateur satellite program!
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------------------------------
End of AMSAT-BB Digest, Vol 13, Issue 119
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