| |
CX2SA > SATDIG 03.06.16 08:55l 1027 Lines 39398 Bytes #999 (0) @ WW
BID : AMSATBB11180
Read: GUEST
Subj: AMSAT-BB-digest V11 180
Path: IW8PGT<CX2SA
Sent: 160603/0637Z @:CX2SA.SAL.URY.SOAM #:44743 [Salto] FBB7.00e $:AMSATBB11180
From: CX2SA@CX2SA.SAL.URY.SOAM
To : SATDIG@WW
Today's Topics:
1. Re: EsHail Microwave transponder satellite (Edward R Cole)
2. Re: EsHail Microwave transponder satellite
(Michael R. Lengruesser)
3. KISS-RX AA2TX info (Joel Caulkins)
4. Does SO-50 Tumble? Was: "Polarization" (Ken Alexander)
5. Re: Does SO-50 Tumble? Was: "Polarization" (Robert Bruninga)
6. Re: Does SO-50 Tumble? Was: "Polarization" (Ted)
7. Re: Does SO-50 Tumble? Was: "Polarization" (Andrew Glasbrenner)
8. [Video] Rare MAI-75 USA ISS SSTV Reception - April 2016 Video
#3 (John Brier)
9. Upcoming ARISS Contact Schedule as of 2016-06-03 06:00 UTC
(AJ9N@xxx.xxxx
----------------------------------------------------------------------
Message: 1
Date: Thu, 02 Jun 2016 13:02:38 -0800
From: Edward R Cole <kl7uw@xxxxxxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: Re: [amsat-bb] EsHail Microwave transponder satellite
Message-ID: <201606022102.u52L2c9U032535@xxxxxxxxx.xxxxxxxxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"; format=flowed
Comments *** inserted, below:
---------------
Date: Thu, 2 Jun 2016 12:05:13 +0200
From: Remco <pa3fym@xxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] EsHail Microwave transponder satellite
Message-ID: <201606021205.13732.pa3fym@xxxxx.xxx>
Content-Type: text/plain; charset="us-ascii"
Having posted my setup at the end of last month and
seeing that my mail program wrapped line feeds, decreasing
readibility, here again my description and perspective.
Es'hail2 will not differ from any other geostationary broadcast satellite
in a sense that it's a 'full duplex' repeater with some time delay.
I reckon this time delay inhibits actual full duplex operation,
just like the TV reporter for a 'live stand up' in the TV news via
a satellite link having an earplug with all audio except himself ('N-1').
***Why? Duplex is totally possible - just listening to your own
retransmitted voice might mess up your mind too much. I suggest
probably muting the receiver when you talk (simple VOX controlling Rx
audio). Rx resumes immediately upon cease of talking. Disable to
tune in your signal using carrier.
====snipped
Feed:
From my perspective the only challenge lies in the 2.4 GHz uplink.
That is, to make an S-band feed which phase center coincides with the
10.5 GHz LNB (which has its own 'feed' ;-)
***LNB "is" a feed with block down-conversion (e.g. Low Noise
Block-down-converter)
I've no fear for isolation issues due to the large frequency difference.
***Probably true as wg for 10-GHz LNB cuts off way above the uplink frequency.
I am told that circular polarization (CP) is 'mandatory' for S-band
uplink's in general but can't find a verification for this,
perhaps somebody else?
***Generally, I am hearing that the s/c will have linear antennas
whose orientation will change depending on your lat-long on
earth. Common issue for eme'rs separated by large differences in
coordinates (term is called spacial loss but refers to polarization
angle shift with apparent location in respect to the other station).
***CP should solve this for the ground station; but designing and
building a mw CP feed is not easy.
Anyway, we're amateurs and creative. So when RHCP uplink is too
difficult we make a linear antenna and increase uplink power with 3 dB ;-)
***Huh? That would only be true if s/c is circular pol. If it is
linear you could have a loss all the way to 20-dB depending on
polarity mismatch (see spacial loss referred to above)
But, I follow the published receiver specifications . . .
Last week I made a 6 turn LHCP 2.4 GHz helix.
(Rule of thumb seems to be 1 turn per 0.1 f/D)
Phase center of such a helix is a bit 'foggy' but from what I read lies
somewhere between the first and second turn.
I've some issues with matching it due to some mechanical boundary conditions
of the helix feed point in conjunction with the mounted downlink LNB and
relative position of the helix.
There is an additional 'transmission line' involved and
a 'normal' 1/4-wave stub doesn't give me the desired return loss.
So, this needs some fiddling, perhaps with a gamma match or so.
***I used a 33-inch offset fed dish on 2.4-GHz with a 6-1/4 turn
helical feed for AO-40. I used brass strap for the first 1/4 WL to
match the feed to coax. Matching is done by adjusting the height of
the matching section from the ground plane. I ended up with 3/16
inch separation at helix end of matching line.
My approach is, the downlink LNB is mounted in the dish 'as usual' and
looks through the centre of the uplink helix.
***If the 10-GHz feed is generally cylindrical and smaller diameter
than the Helix this will work fine. I used a metal tube with heat
sink covering as center support for my helix. 0.7-inch ID tubing is
proper diameter for 10-GHz wg. But not sure how well the typical
12-GHz LNB will work inside a helix.
***Other geosat designs are for 5-GHz/10-GHz so not sure how well a
Helix will work there. Perhaps the 10-GHz cylindrical wg could serve
as center conductor of air-insulated coaxial feed with a simple
dipole feed on 5-GHz and 10-GHz horn extending a small way beyond the
dipole. This would work better with center-fed dishes of f/d ~ 0.35.
Pictures of the prototype feed arrangement can be provided soon.
They are on a camera not present here at this moment of writing.
***Attachments to Amsat-BB probably will not go thru; post http link
to the photos, instead - please.
Remco PA3FYM
73, Ed - KL7UW
http://www.kl7uw.com
"Kits made by KL7UW"
Dubus Mag business:
dubususa@xxxxx.xxx
------------------------------
Message: 2
Date: Fri, 3 Jun 2016 00:24:35 +0200
From: "Michael R. Lengruesser" <mlengruesser@xxxxxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: Re: [amsat-bb] EsHail Microwave transponder satellite
Message-ID: <a7a13116-a761-7dcb-39f5-068bccdc6580@xxxxxxxx.xxx>
Content-Type: text/plain; charset=windows-1252
The S-band RX antnna at Es?hailsat-2 is a RHCP antenna
NB and WB TWTA?s are feeding a Orthomode transducer (OMT) with horn antenna
So X band TX NB is V and X band TX WB is H polarisation.
73 de
Michael R. Lengruesser, DD5ER
AMSAT-DL e.V.
-- International Satellites for
Communication, Science and Education --
mlengruesser@xxxxxxxx.xxx
http:/www.amsat-dl.org
Am 02.06.2016 um 23:02 schrieb Edward R Cole:
> Comments *** inserted, below:
> ---------------
> Date: Thu, 2 Jun 2016 12:05:13 +0200
> From: Remco <pa3fym@xxxxx.xxx>
> To: amsat-bb@xxxxx.xxx
> Subject: [amsat-bb] EsHail Microwave transponder satellite
> Message-ID: <201606021205.13732.pa3fym@xxxxx.xxx>
> Content-Type: text/plain; charset="us-ascii"
>
> Having posted my setup at the end of last month and
> seeing that my mail program wrapped line feeds, decreasing
> readibility, here again my description and perspective.
>
>
> Es'hail2 will not differ from any other geostationary broadcast satellite
> in a sense that it's a 'full duplex' repeater with some time delay.
>
>
> I reckon this time delay inhibits actual full duplex operation,
> just like the TV reporter for a 'live stand up' in the TV news via
> a satellite link having an earplug with all audio except himself ('N-1').
>
> ***Why? Duplex is totally possible - just listening to your own
> retransmitted voice might mess up your mind too much. I suggest
> probably muting the receiver when you talk (simple VOX controlling Rx
> audio). Rx resumes immediately upon cease of talking. Disable to tune
> in your signal using carrier.
>
> ====snipped
>
>
> Feed:
> From my perspective the only challenge lies in the 2.4 GHz uplink.
> That is, to make an S-band feed which phase center coincides with the
> 10.5 GHz LNB (which has its own 'feed' ;-)
>
> ***LNB "is" a feed with block down-conversion (e.g. Low Noise
> Block-down-converter)
>
> I've no fear for isolation issues due to the large frequency difference.
>
> ***Probably true as wg for 10-GHz LNB cuts off way above the uplink
> frequency.
>
> I am told that circular polarization (CP) is 'mandatory' for S-band
> uplink's in general but can't find a verification for this,
> perhaps somebody else?
>
> ***Generally, I am hearing that the s/c will have linear antennas whose
> orientation will change depending on your lat-long on earth. Common
> issue for eme'rs separated by large differences in coordinates (term is
> called spacial loss but refers to polarization angle shift with apparent
> location in respect to the other station).
>
> ***CP should solve this for the ground station; but designing and
> building a mw CP feed is not easy.
>
> Anyway, we're amateurs and creative. So when RHCP uplink is too
> difficult we make a linear antenna and increase uplink power with 3 dB ;-)
>
> ***Huh? That would only be true if s/c is circular pol. If it is
> linear you could have a loss all the way to 20-dB depending on polarity
> mismatch (see spacial loss referred to above)
>
> But, I follow the published receiver specifications . . .
> Last week I made a 6 turn LHCP 2.4 GHz helix.
> (Rule of thumb seems to be 1 turn per 0.1 f/D)
> Phase center of such a helix is a bit 'foggy' but from what I read lies
> somewhere between the first and second turn.
>
> I've some issues with matching it due to some mechanical boundary
> conditions
> of the helix feed point in conjunction with the mounted downlink LNB and
> relative position of the helix.
> There is an additional 'transmission line' involved and
> a 'normal' 1/4-wave stub doesn't give me the desired return loss.
> So, this needs some fiddling, perhaps with a gamma match or so.
>
> ***I used a 33-inch offset fed dish on 2.4-GHz with a 6-1/4 turn helical
> feed for AO-40. I used brass strap for the first 1/4 WL to match the
> feed to coax. Matching is done by adjusting the height of the matching
> section from the ground plane. I ended up with 3/16 inch separation at
> helix end of matching line.
>
> My approach is, the downlink LNB is mounted in the dish 'as usual' and
> looks through the centre of the uplink helix.
>
> ***If the 10-GHz feed is generally cylindrical and smaller diameter than
> the Helix this will work fine. I used a metal tube with heat sink
> covering as center support for my helix. 0.7-inch ID tubing is proper
> diameter for 10-GHz wg. But not sure how well the typical 12-GHz LNB
> will work inside a helix.
>
> ***Other geosat designs are for 5-GHz/10-GHz so not sure how well a
> Helix will work there. Perhaps the 10-GHz cylindrical wg could serve as
> center conductor of air-insulated coaxial feed with a simple dipole feed
> on 5-GHz and 10-GHz horn extending a small way beyond the dipole. This
> would work better with center-fed dishes of f/d ~ 0.35.
>
> Pictures of the prototype feed arrangement can be provided soon.
> They are on a camera not present here at this moment of writing.
>
> ***Attachments to Amsat-BB probably will not go thru; post http link to
> the photos, instead - please.
>
> Remco PA3FYM
>
>
> 73, Ed - KL7UW
> http://www.kl7uw.com
> "Kits made by KL7UW"
> Dubus Mag business:
> dubususa@xxxxx.xxx
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx. 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: 3
Date: Thu, 2 Jun 2016 15:59:09 -0700
From: Joel Caulkins <caulktel@xxxxx.xxx>
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] KISS-RX AA2TX info
Message-ID:
<CAHm=03cBrSTJGArkNLDkBzDo1SKcY38rRWpnoxXyeGy06=y5mA@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
Hi,
Can anybody point me in the direction of any information on Anthony,
AA2TX's Space Radio SDR receiver. I have bought a PCB from
Amateurradiokits.in. I need the KISS-RX driver and the WAVE I/O driver for
Windows. Any help would be appreciated.
--
Joel, KB6QVI
------------------------------
Message: 4
Date: Thu, 2 Jun 2016 19:28:58 -0400
From: Ken Alexander <k.alexander@xxxxxx.xxx>
To: Bob <WB4SON@xxxxx.xxx>
Cc: AMSAT-BB <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] Does SO-50 Tumble? Was: "Polarization"
Message-ID: <637FCE7D-0190-492D-AE8B-E453D7CD35AB@xxxxxx.xxx>
Content-Type: text/plain; charset=utf-8
So far, I am only active on SO-50 and I have to say I?m impressed with the
reception quality with my TH-D72A and Arrow antenna. The Arrow requires
only a twist to peak the signal to very good levels. I?m starting to notice
a pattern where certain polarization angles produce the best results at
different times during a pass. It would be interesting if this turned out
to be repeatable?and it leads to my next question: How much (if at all)
does SO-50 or any other satellite tumble during its orbit? I am assuming
that the current breed of ham satellites aren?t large enough to house motors
or other devices to control their attitude, which makes me think they must
tumble somewhat.
Once again, thank you all for your forbearance as I mine your collective
knowledge to bring myself up to speed!
73,
Ken Alexander
VE3HLS
> On May 31, 2016, at 1:51 PM, Bob <WB4SON@xxxxx.xxx> wrote:
>
> "The antennas I see in the photos of satellites we work are whips. Is the
polarization becoming "circularized" as it re-enters earth's atmosphere or
something?"
>
> Yep, that is exactly what is happening. It is called Faraday Rotation,
and as the signal from the satellite passes through the ionosphere, all
sorts of polarity changes can and do happen. A linear polarized satellite
antenna (horizontal or vertical) can appear to be the opposite or somewhere
in between. That's why folks rotate their Arrow or Elk antennas -- trying
to match the polarity.
>
> Using a circular polarized antenna helps a bunch -- it doesn't matter what
the polarity of the linear satellite antenna happens to be at any moment in
time.
>
> But there is no free lunch -- Even a circular polarized antenna might need
to be switched from Right Hand Circular Polarization (the default) to LHCP
from time to time depending on what nasty thing the ionosphere is doing at
any given moment. Changing the polarity switch might bring a S0 signal up
to S5, a 30 dB improvement. I had that happen to me during a recent ARISS
contact.
>
> 73, Bob, WB4SON
>
>
>
> On Mon, May 30, 2016 at 8:25 PM, Doug Andrews <dougg27@xxxxxxx.xxx
<mailto:dougg27@xxxxxxx.xxx>> wrote:
>
>
> I too have wondered about this.
> I have not had much trouble hitting SO-50 and some success on AO-85 with a
5 watt handheld and arrow antenna without turning it. Worth a try.
> DougKG7UNU
>
>
>
> Sent from my Sprint Samsung Galaxy? Note 4.
>
> -------- Original message --------
> From: Ken Alexander <k.alexander@xxxxxx.xxx <mailto:k.alexander@xxxxxx.xxx>>
> Date: 5/30/16 4:41 PM (GMT-08:00)
> To: amsat-bb@xxxxx.xxx <mailto:amsat-bb@xxxxx.xxx>
> Subject: [amsat-bb] Polarization
>
> I clipped this from another message because I didn't want to drag the
> discussion off course. It's a question I've been wondering about since
> getting into this a few short weeks ago.
>
> I've also read (but haven't tried yet) about the trick of rotating
> the antenna 90 degrees on transmit, once you've established the best
> receive orientation.
>
> 73 de Bill, KG5FQX
>
> So far, with SO-20 I have rotated my Arrow antenna for best reception of
> the downlink and don't think I've had too much trouble being heard. At
> the same time I have wondered whether I should twist the antenna when
> transmitting to orient the 2m elements to give the same polarization as
> in receive. I don't know if this is a good idea or not, and frankly I
> have enough trouble remembering calls and grids, tracking the satellite,
> adjusting frequency and switching back to the correct VFO to worry about
> one more thing.
>
> I've seen that some commercial OSCAR antennas use circular polarization.
> The antennas I see in the photos of satellites we work are whips. Is the
> polarization becoming "circularized" as it re-enters earth's atmosphere
> or something?
>
> Comments and observations would be most welcome!
>
> 73,
>
> Ken Alexander
> VE3HLS, FN03
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx <mailto:AMSAT-BB@xxxxx.xxx>. 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
<http://www.amsat.org/mailman/listinfo/amsat-bb>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx <mailto:AMSAT-BB@xxxxx.xxx>. 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
<http://www.amsat.org/mailman/listinfo/amsat-bb>
>
------------------------------
Message: 5
Date: Thu, 2 Jun 2016 19:40:01 -0400
From: Robert Bruninga <bruninga@xxxx.xxx>
To: AMSAT-BB <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] Does SO-50 Tumble? Was: "Polarization"
Message-ID: <66ebc9ae76303adf0bc08a0a58df1191@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
PCSAT spins at about 0.6 RPM and PSAT spins between 3 and 6 PM and you can
decode the telemetry easily with a pen and paper to see what it is currently
doing. http://aprs.org/psat.html
Even if a satellite did not spin at all, it would still rotate relative to
you almost 180 degrees from horizon to horizon. Bob, WB4aPR
-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces@xxxxx.xxxx On Behalf Of Ken
Alexander
Sent: Thursday, June 02, 2016 7:29 PM
To: Bob
Cc: AMSAT-BB
Subject: [amsat-bb] Does SO-50 Tumble? Was: "Polarization"
So far, I am only active on SO-50 and I have to say I?m impressed with the
reception quality with my TH-D72A and Arrow antenna. The Arrow requires
only a twist to peak the signal to very good levels. I?m starting to notice
a pattern where certain polarization angles produce the best results at
different times during a pass. It would be interesting if this turned out
to be repeatable?and it leads to my next question: How much (if at all)
does SO-50 or any other satellite tumble during its orbit? I am assuming
that the current breed of ham satellites aren?t large enough to house motors
or other devices to control their attitude, which makes me think they must
tumble somewhat.
Once again, thank you all for your forbearance as I mine your collective
knowledge to bring myself up to speed!
73,
Ken Alexander
VE3HLS
> On May 31, 2016, at 1:51 PM, Bob <WB4SON@xxxxx.xxx> wrote:
>
> "The antennas I see in the photos of satellites we work are whips. Is the
> polarization becoming "circularized" as it re-enters earth's atmosphere or
> something?"
>
> Yep, that is exactly what is happening. It is called Faraday Rotation,
> and as the signal from the satellite passes through the ionosphere, all
> sorts of polarity changes can and do happen. A linear polarized satellite
> antenna (horizontal or vertical) can appear to be the opposite or
> somewhere in between. That's why folks rotate their Arrow or Elk
> antennas -- trying to match the polarity.
>
> Using a circular polarized antenna helps a bunch -- it doesn't matter what
> the polarity of the linear satellite antenna happens to be at any moment
> in time.
>
> But there is no free lunch -- Even a circular polarized antenna might need
> to be switched from Right Hand Circular Polarization (the default) to LHCP
> from time to time depending on what nasty thing the ionosphere is doing at
> any given moment. Changing the polarity switch might bring a S0 signal up
> to S5, a 30 dB improvement. I had that happen to me during a recent ARISS
> contact.
>
> 73, Bob, WB4SON
>
>
>
> On Mon, May 30, 2016 at 8:25 PM, Doug Andrews <dougg27@xxxxxxx.xxx
> <mailto:dougg27@xxxxxxx.xxx>> wrote:
>
>
> I too have wondered about this.
> I have not had much trouble hitting SO-50 and some success on AO-85 with a
> 5 watt handheld and arrow antenna without turning it. Worth a try.
> DougKG7UNU
>
>
>
> Sent from my Sprint Samsung Galaxy? Note 4.
>
> -------- Original message --------
> From: Ken Alexander <k.alexander@xxxxxx.xxx
> <mailto:k.alexander@xxxxxx.xxx>>
> Date: 5/30/16 4:41 PM (GMT-08:00)
> To: amsat-bb@xxxxx.xxx <mailto:amsat-bb@xxxxx.xxx>
> Subject: [amsat-bb] Polarization
>
> I clipped this from another message because I didn't want to drag the
> discussion off course. It's a question I've been wondering about
> since getting into this a few short weeks ago.
>
> I've also read (but haven't tried yet) about the trick of rotating the
> antenna 90 degrees on transmit, once you've established the best
> receive orientation.
>
> 73 de Bill, KG5FQX
>
> So far, with SO-20 I have rotated my Arrow antenna for best reception
> of the downlink and don't think I've had too much trouble being heard.
> At the same time I have wondered whether I should twist the antenna
> when transmitting to orient the 2m elements to give the same
> polarization as in receive. I don't know if this is a good idea or
> not, and frankly I have enough trouble remembering calls and grids,
> tracking the satellite, adjusting frequency and switching back to the
> correct VFO to worry about one more thing.
>
> I've seen that some commercial OSCAR antennas use circular polarization.
> The antennas I see in the photos of satellites we work are whips. Is
> the polarization becoming "circularized" as it re-enters earth's
> atmosphere or something?
>
> Comments and observations would be most welcome!
>
> 73,
>
> Ken Alexander
> VE3HLS, FN03
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx <mailto:AMSAT-BB@xxxxx.xxx>. 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
> <http://www.amsat.org/mailman/listinfo/amsat-bb>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx <mailto:AMSAT-BB@xxxxx.xxx>. 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
> <http://www.amsat.org/mailman/listinfo/amsat-bb>
>
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. 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: 6
Date: Thu, 2 Jun 2016 16:48:21 -0700
From: "Ted" <k7trkradio@xxxxxxx.xxx>
To: "'Ken Alexander'" <k.alexander@xxxxxx.xxx>, "'Bob'"
<WB4SON@xxxxx.xxx>
Cc: 'AMSAT-BB' <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] Does SO-50 Tumble? Was: "Polarization"
Message-ID: <002701d1bd29$3f8589c0$be909d40$@xxxxxxx.xxx>
Content-Type: text/plain; charset="UTF-8"
Good question, Ken. I have the same issues with AO-85. I have an Elk on a
rotor but fixed at 15 deg EL. Lots of 'in and out' reception.(I have been
told AO-85 tumbles) I think I'm going to resurrect my 2m turnstile Moxon and
see what happens. I have the Arrow but hate using it outdoors
73, ted
K7TRK
-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces@xxxxx.xxxx On Behalf Of Ken Alexander
Sent: Thursday, June 02, 2016 4:29 PM
To: Bob
Cc: AMSAT-BB
Subject: [amsat-bb] Does SO-50 Tumble? Was: "Polarization"
So far, I am only active on SO-50 and I have to say I?m impressed with the
reception quality with my TH-D72A and Arrow antenna. The Arrow requires
only a twist to peak the signal to very good levels. I?m starting to notice
a pattern where certain polarization angles produce the best results at
different times during a pass. It would be interesting if this turned out
to be repeatable?and it leads to my next question: How much (if at all)
does SO-50 or any other satellite tumble during its orbit? I am assuming
that the current breed of ham satellites aren?t large enough to house motors
or other devices to control their attitude, which makes me think they must
tumble somewhat.
Once again, thank you all for your forbearance as I mine your collective
knowledge to bring myself up to speed!
73,
Ken Alexander
VE3HLS
> On May 31, 2016, at 1:51 PM, Bob <WB4SON@xxxxx.xxx> wrote:
>
> "The antennas I see in the photos of satellites we work are whips. Is the
polarization becoming "circularized" as it re-enters earth's atmosphere or
something?"
>
> Yep, that is exactly what is happening. It is called Faraday Rotation,
and as the signal from the satellite passes through the ionosphere, all
sorts of polarity changes can and do happen. A linear polarized satellite
antenna (horizontal or vertical) can appear to be the opposite or somewhere
in between. That's why folks rotate their Arrow or Elk antennas -- trying
to match the polarity.
>
> Using a circular polarized antenna helps a bunch -- it doesn't matter what
the polarity of the linear satellite antenna happens to be at any moment in
time.
>
> But there is no free lunch -- Even a circular polarized antenna might need
to be switched from Right Hand Circular Polarization (the default) to LHCP
from time to time depending on what nasty thing the ionosphere is doing at
any given moment. Changing the polarity switch might bring a S0 signal up
to S5, a 30 dB improvement. I had that happen to me during a recent ARISS
contact.
>
> 73, Bob, WB4SON
>
>
>
> On Mon, May 30, 2016 at 8:25 PM, Doug Andrews <dougg27@xxxxxxx.xxx
<mailto:dougg27@xxxxxxx.xxx>> wrote:
>
>
> I too have wondered about this.
> I have not had much trouble hitting SO-50 and some success on AO-85 with a
5 watt handheld and arrow antenna without turning it. Worth a try.
> DougKG7UNU
>
>
>
> Sent from my Sprint Samsung Galaxy? Note 4.
>
> -------- Original message --------
> From: Ken Alexander <k.alexander@xxxxxx.xxx
> <mailto:k.alexander@xxxxxx.xxx>>
> Date: 5/30/16 4:41 PM (GMT-08:00)
> To: amsat-bb@xxxxx.xxx <mailto:amsat-bb@xxxxx.xxx>
> Subject: [amsat-bb] Polarization
>
> I clipped this from another message because I didn't want to drag the
> discussion off course. It's a question I've been wondering about
> since getting into this a few short weeks ago.
>
> I've also read (but haven't tried yet) about the trick of rotating the
> antenna 90 degrees on transmit, once you've established the best
> receive orientation.
>
> 73 de Bill, KG5FQX
>
> So far, with SO-20 I have rotated my Arrow antenna for best reception
> of the downlink and don't think I've had too much trouble being heard.
> At the same time I have wondered whether I should twist the antenna
> when transmitting to orient the 2m elements to give the same
> polarization as in receive. I don't know if this is a good idea or
> not, and frankly I have enough trouble remembering calls and grids,
> tracking the satellite, adjusting frequency and switching back to the
> correct VFO to worry about one more thing.
>
> I've seen that some commercial OSCAR antennas use circular polarization.
> The antennas I see in the photos of satellites we work are whips. Is
> the polarization becoming "circularized" as it re-enters earth's
> atmosphere or something?
>
> Comments and observations would be most welcome!
>
> 73,
>
> Ken Alexander
> VE3HLS, FN03
>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx <mailto:AMSAT-BB@xxxxx.xxx>. 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
> <http://www.amsat.org/mailman/listinfo/amsat-bb>
> _______________________________________________
> Sent via AMSAT-BB@xxxxx.xxx <mailto:AMSAT-BB@xxxxx.xxx>. 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
> <http://www.amsat.org/mailman/listinfo/amsat-bb>
>
_______________________________________________
Sent via AMSAT-BB@xxxxx.xxx. 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: 7
Date: Thu, 2 Jun 2016 20:07:03 -0400
From: Andrew Glasbrenner <glasbrenner@xxxxxxxxxx.xxx>
To: Ken Alexander <k.alexander@xxxxxx.xxx>
Cc: AMSAT-BB <amsat-bb@xxxxx.xxx>
Subject: Re: [amsat-bb] Does SO-50 Tumble? Was: "Polarization"
Message-ID: <2CC0B470-8D14-469D-9061-3622C87938BF@xxxxxxxxxx.xxx>
Content-Type: text/plain; charset=utf-8
Most us passive magnetic stabilization and some sort of solar pressure
induced spin. They "tumble" crossing the magnetic equator, and wobble
elsewhere.
73, Drew KO4MA
> On Jun 2, 2016, at 7:28 PM, Ken Alexander <k.alexander@xxxxxx.xxx> wrote:
>
> So far, I am only active on SO-50 and I have to say I?m impressed with the
reception quality with my TH-D72A and Arrow antenna. The Arrow requires
only a twist to peak the signal to very good levels. I?m starting to notice
a pattern where certain polarization angles produce the best results at
different times during a pass. It would be interesting if this turned out
to be repeatable?and it leads to my next question: How much (if at all)
does SO-50 or any other satellite tumble during its orbit? I am assuming
that the current breed of ham satellites aren?t large enough to house motors
or other devices to control their attitude, which makes me think they must
tumble somewhat.
>
> Once again, thank you all for your forbearance as I mine your collective
knowledge to bring myself up to speed!
>
> 73,
>
> Ken Alexander
> VE3HLS
>
>
>> On May 31, 2016, at 1:51 PM, Bob <WB4SON@xxxxx.xxx> wrote:
>>
>> "The antennas I see in the photos of satellites we work are whips. Is the
polarization becoming "circularized" as it re-enters earth's atmosphere or
something?"
>>
>> Yep, that is exactly what is happening. It is called Faraday Rotation,
and as the signal from the satellite passes through the ionosphere, all
sorts of polarity changes can and do happen. A linear polarized satellite
antenna (horizontal or vertical) can appear to be the opposite or somewhere
in between. That's why folks rotate their Arrow or Elk antennas -- trying
to match the polarity.
>>
>> Using a circular polarized antenna helps a bunch -- it doesn't matter
what the polarity of the linear satellite antenna happens to be at any
moment in time.
>>
>> But there is no free lunch -- Even a circular polarized antenna might
need to be switched from Right Hand Circular Polarization (the default) to
LHCP from time to time depending on what nasty thing the ionosphere is doing
at any given moment. Changing the polarity switch might bring a S0 signal
up to S5, a 30 dB improvement. I had that happen to me during a recent
ARISS contact.
>>
>> 73, Bob, WB4SON
>>
>>
>>
>> On Mon, May 30, 2016 at 8:25 PM, Doug Andrews <dougg27@xxxxxxx.xxx
<mailto:dougg27@xxxxxxx.xxx>> wrote:
>>
>>
>> I too have wondered about this.
>> I have not had much trouble hitting SO-50 and some success on AO-85 with
a 5 watt handhel
------------------------------
Message: 8
Date: Fri, 3 Jun 2016 00:10:59 -0400
From: John Brier <johnbrier@xxxxx.xxx>
To: AMSAT BB <amsat-bb@xxxxx.xxx>
Subject: [amsat-bb] [Video] Rare MAI-75 USA ISS SSTV Reception - April
2016 Video #3
Message-ID:
<CALn0fKO5e06Hed3zXAXEXizcmmEAh-fnL2A0PYX4Mdx6T5jMYA@xxxx.xxxxx.xxx>
Content-Type: text/plain; charset=UTF-8
https://youtu.be/cUnkrlRJJuw
MAI-75 ISS SSTV was mostly only available outside of North America,
but there were two passes where it did cover NA on Friday April 15th,
2016. This is one of those passes.
Video #1 - Monday Failure and Tuesday Success
https://youtu.be/ieR-nmkjeSc
Video #2 - Perfect ISS SSTV Images... Almost!
https://youtu.be/JoFrVRfc4Ks
73,
John KG4AKV
------------------------------
Message: 9
Date: Fri, 3 Jun 2016 02:35:50 -0400
From: AJ9N@xxx.xxx
To: amsat-bb@xxxxx.xxx
Subject: [amsat-bb] Upcoming ARISS Contact Schedule as of 2016-06-03
06:00 UTC
Message-ID: <d2c40.5696d53.44827f46@xxx.xxx>
Content-Type: text/plain; charset="ISO-8859-1"
Upcoming ARISS Contact Schedule as of 2016-06-03 06:00 UTC
Quick list of scheduled contacts and events:
Bouze Island Elementary and Junior High School, Homeji, Japan, direct via
8N3B
The ISS callsign is presently scheduled to be NA1SS
The scheduled astronaut is Timothy Peake KG5BVI
Contact is a go for: Sat 2016-06-04 08:31:09 UTC 74 deg
Glenmore State High School, Rockhampton, Queensland, Australia, telebridge
via W6SRJ
The ISS callsign is presently scheduled to be NA1SS
The scheduled astronaut is Tim Kopra KE5UDN
Contact is a go for: Mon 2016-06-06 08:39:31 UTC 31 deg
****************************************************************************
**
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@xxxxx.xxx or aj9n@xxx.xxx.
****************************************************************************
***
All ARISS contacts are made via the Ericsson 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@xxxxxxxxx.xxx
****************************************************************************
ARISS congratulations the following mentors who have now mentored over 100
schools:
Gaston ON4WF with 121
Satoshi 7M3TJZ with 118
Francesco IK?WGF with 116
****************************************************************************
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 8061 date
and
time format YYYY-MM-DD HH:MM:SS
The complete schedule page has been updated as of 2016-06-03 06:00 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
Total number of ARISS ISS to earth school events is 1060.
Each school counts as 1 event.
Total number of ARISS ISS to earth school contacts is 1025.
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 2016-05-31 07:00 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. 46 on orbit
Tim Kopra KE5UDN
Timothy Peake KG5BVI
Yuri Malenchenko RK3DUP
Exp. 47 on orbit
Jeff Williams KD5TVQ
Oleg Skripochka RN3FU
Aleksey Ovchinin
****************************************************************************
73,
Charlie Sufana AJ9N
One of the ARISS operation team mentors
------------------------------
Subject: Digest Footer
_______________________________________________
Sent via amsat-bb@xxxxx.xxx.
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!
http://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
End of AMSAT-BB Digest, Vol 11, Issue 180
*****************************************
Read previous mail | Read next mail
| |
