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CX2SA > SATDIG 19.03.18 21:16l 1092 Lines 40071 Bytes #999 (0) @ WW
BID : AMSATBB13107
Read: GUEST
Subj: AMSAT-BB-digest V13 107
Path: IW8PGT<CX2SA
Sent: 180319/1905Z @:CX2SA.SAL.URY.SOAM #:38118 [Salto] FBB7.00e $:AMSATBB13107
From: CX2SA@CX2SA.SAL.URY.SOAM
To : SATDIG@WW
Today's Topics:
1. Re: AMSAT roundtable on D-Star REF009C - NOW!
(Patrick STODDARD (WD9EWK/VA7EWK))
2. Re: Antenna Polarization Question (Robert Bruninga)
3. Re: Antenna Polarization Question (Jordan Trewitt)
4. Re: Antenna Polarization Question (Franklin Antonio)
5. Re: Antenna Polarization Question (Jean Marc Momple)
6. weekly nets / live chat ? (Mr B r a d)
7. Re: Antenna Polarization Question (Burns Fisher)
8. Re: weekly nets / live chat ? (Dave Taylor)
9. Re: Antenna Polarization Question (Jean Marc Momple)
----------------------------------------------------------------------
Message: 1
Date: Mon, 19 Mar 2018 05:38:17 +0000
From: "Patrick STODDARD (WD9EWK/VA7EWK)" <amsat-bb@??????.???>
To: Rick Tejera <saguaroastro@???.???>
Cc: AMSAT <amsat-bb@?????.???>
Subject: Re: [amsat-bb] AMSAT roundtable on D-Star REF009C - NOW!
Message-ID:
<CAN6TEUcfcwxbn5Eia=mS_pYicct-wGvpGSSYWLcEfbJ00YR8Sw@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Rick,
Other than misspelling AMSAT, the subject of my earlier
message gave those details. It has been held on a D-Star reflector,
REF009C. Several Arizona D-Star repeaters are normally
tied into this reflector. Other repeaters can be used to reach
the reflector. If you have some sort of hotspot at home, or
use a dongle that doesn't require a radio to access D-Star
systems, you can connect directly to the reflector.
Endaf N6UTC was the driving force to get this informal
chat session started a few months ago, for those who use
D-Star. We started using the reflector REF009C, mainly due
to Endaf and I chatting on there. It just happened to be the
reflector that my openSpot hotspot is usually on, and is
hosted in Tucson. We haven't run it as a formal net, preferring
to just talk about satellite-related stuff among whoever
happens to show up.
If you use D-Star, you can check the status of the REF009C
reflector - including repeaters that are currently linked
to this reflector - at:
http://ref009.dstargateway.org/
Patrick WD9EWK/VA7EWK
http://www.wd9ewk.net/
Twitter: @?????? or http://twitter.com/WD9EWK
On Sunday, March 18, 2018, Rick Tejera <saguaroastro@???.???> wrote:
> Is this an HF net, echolink or IRLP? Frequencies or nodes?
>
>
>
> Rick Tejera K7TEJ
> Saguaro Astronomy Club
> www.saguaroastro.org
> Thunderbird Amateur Radio Club
> www.w7tbc.org
>
>
>
> *From: *Patrick STODDARD (WD9EWK/VA7EWK) <amsat-bb@??????.???>
> *Sent: *Sunday, March 18, 2018 19:47
> *To: *AMSAT <amsat-bb@?????.???>
> *Subject: *[amsat-bb] Unofficial AMSAST roundtable on D-Star REF009C -
> NOW!
>
>
>
> Hi!
>
>
>
> After a couple of weeks of no activity, we are trying to get
>
> back to the Sunday evening AMSAT roundtable we had been doing
>
> for a few months. With the shift to daylight time last weekend,
>
> we moved the start time of the roundtable to 7.30pm PDT (10.30pm
>
> EDT, or Monday 0230 UTC). A few of us are on there now, and we
>
> will try this starting time to see how it works.
>
>
>
> 73!
>
>
>
>
>
>
>
>
>
> Patrick WD9EWK/VA7EWK
>
> http://www.wd9ewk.net/
>
> Twitter: @?????? or http://twitter.com/WD9EWK
>
> _______________________________________________
>
> 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: Mon, 19 Mar 2018 09:08:52 -0400
From: Robert Bruninga <bruninga@????.???>
To: amsat-bb@?????.???
Subject: Re: [amsat-bb] Antenna Polarization Question
Message-ID: <42e3de2afc777f986928ab096c5a004e@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Another way to understand it is that the if in any given direction the
combination of the emission from a cubesat with only one or two antenna
elements appears RHCP in one direction, it will appear LHCP in the
opposite direction to the same extent.
So during a pass or due to tumbling, you can see both
I think.
Bob, WB4aPR
-----Original Message-----
From: AMSAT-BB [mailto:amsat-bb-bounces@?????.???? On Behalf Of Greg D
Sent: Sunday, March 18, 2018 10:21 PM
To: Burns Fisher <burns@??????.??>; Eduardo PY2RN <py2rn@????.???>
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] Antenna Polarization Question
Hi Burns,
I've experienced that too, and from a little research I think it has more
to do with mechanics, and less physics. The thought is that no CP antenna
is perfectly circular, and so has a linear component to the pattern. That
linear component's alignment, or mis-alignment, with the satellite's
antenna causes some fading. Flipping the handedness also changes the
angle of that linear part, so it can help (or hurt) the reception.
At least, that's the theory. There may also be reflections from buildings
and the planet that will introduce a linear component to the signal, and
perhaps some atmospheric effects as well.
Greg KO6TH
Burns Fisher wrote:
> Indeed, CP makes sense with a linear tx when you can't tell what the
> orientation would be. You give up a few dB to avoid deep fades. But
> I just can't figure out why you need to switch from RHP to LHP in such
> cases. I've heard a number of people say that it sometimes matters,
> but I don't understand the physics!
>
> 73,
>
> Burns WB1FJ
>
> On Sun, Mar 18, 2018 at 6:06 PM, Eduardo PY2RN <py2rn@????.???> wrote:
>
>> Jordan, most of the amateur radio LEOs SATs today have a linear
>> polarized antenna attached, it is not possible to know which position
>> it is in the time of the pass: H, V, moving, spinning... being
>> completely random to the ground station which polarization the signal
>> will be, for this reason I believe CP is more efficient but with RH/LH
switching capability.
>> 73
>> Ed
>> PY2RN
>> From: Jordan Trewitt <jmtrewitt@?????.???>
>> To: Eduardo PY2RN <py2rn@????.???>
>> Cc: Brian <cqkg8co@?????.???>; "amsat-bb@?????.????
>> <amsat-bb@?????.???>
>> Sent: Sunday, March 18, 2018 6:44 PM
>> Subject: Re: [amsat-bb] Antenna Polarization Question
>>
>> Maybe I'm not understanding it, but why does one need to switch
>> between both, unless a particular satellite has LHCP or
>> RHCP?JordanKF5COQ
>>
>> On Sun, Mar 18, 2018, 16:34 Eduardo PY2RN <py2rn@????.???> wrote:
>>
>> Hi Brian,
>> Both. You are going to need to switch between RHCP and LHCP often
>> during a sat pass. The same happens if using linear polarization
>> (V/H) but in this case the switch between V and H will happen much more
often than in CP.
>> 73
>> Ed
>> PY2RN
>>
>> From: Brian via AMSAT-BB <amsat-bb@?????.???>
>> To: "amsat-bb@?????.???? <amsat-bb@?????.???>
>> Sent: Sunday, March 18, 2018 6:21 PM
>> Subject: [amsat-bb] Antenna Polarization Question
>>
>>
>>
>> Should I be using LHCP or RHCP when setting up the 2 meter and 440
>> yagi's to work the LEO's.
>>
>> Thank you
>>
>> Brian, KG8CO
>>
>> _______________________________________________
>> 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
_______________________________________________
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: 3
Date: Sun, 18 Mar 2018 21:43:49 +0000
From: Jordan Trewitt <jmtrewitt@?????.???>
To: Eduardo PY2RN <py2rn@????.???>
Cc: "amsat-bb@?????.???? <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Antenna Polarization Question
Message-ID:
<CAHD9BgAb3cbovOjP_wHwmt+-t3VJ-AtMYKn__YEZfoBhs9dHcA@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Maybe I'm not understanding it, but why does one need to switch between
both, unless a particular satellite has LHCP or RHCP?
Jordan
KF5COQ
On Sun, Mar 18, 2018, 16:34 Eduardo PY2RN <py2rn@????.???> wrote:
> Hi Brian,
> Both. You are going to need to switch between RHCP and LHCP often during a
> sat pass. The same happens if using linear polarization (V/H) but in this
> case the switch between V and H will happen much more often than in CP.
> 73
> Ed
> PY2RN
>
> From: Brian via AMSAT-BB <amsat-bb@?????.???>
> To: "amsat-bb@?????.???? <amsat-bb@?????.???>
> Sent: Sunday, March 18, 2018 6:21 PM
> Subject: [amsat-bb] Antenna Polarization Question
>
>
>
> Should I be using LHCP or RHCP when setting up the 2 meter and 440 yagi's
> to work the LEO's.
>
> Thank you
>
> Brian, KG8CO
>
> _______________________________________________
> 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: 4
Date: Mon, 19 Mar 2018 16:54:01 +0000
From: Franklin Antonio <antonio@???.????????.???>
To: Jordan Trewitt <jmtrewitt@?????.???>, Eduardo PY2RN
<py2rn@????.???>
Cc: "amsat-bb@?????.???? <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Antenna Polarization Question
Message-ID: <1521478441376.95121@???.????????.???>
Content-Type: text/plain; charset="iso-8859-1"
When you say a satellite "has" RHCP, we have to be careful that we're
communicating clearly about what "has" means. Every satellite "has" both,
by virtue of he way antennas work.
I suspect that you mean that the satellite has an antenna which transmits
RHCP in its main lobe. It is important to realize that the signal from such
an antenna is only RHCP in its main lobe. The sidelobes are gonna be LHCP.
In between, you can get anything in between. So if a satellite is oriented
so that its antenna points right at you, and they designed it to be RHCP,
then that's what you're gonna get, but if it is pointing off to the side,
then you get something else.
This means that there are situations in which you might get a stronger
received signal if you switch to LHCP, or maybe even to linear. In the
commercial satellite biz, they design satellites so that their antennas
point at the users. Hams build cheaper satellites, which typically don't
have sophisticated attitude control, so sometimes they point away from you.
Also, hams try to use the things even when conditions aren't the best. If
that's your aim, then most folks have found that polarization switching
sometimes helps.
________________________________________
From: AMSAT-BB <amsat-bb-bounces@?????.???> on behalf of Jordan Trewitt
<jmtrewitt@?????.???>
Sent: Sunday, March 18, 2018 2:43 PM
To: Eduardo PY2RN
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] Antenna Polarization Question
Maybe I'm not understanding it, but why does one need to switch between
both, unless a particular satellite has LHCP or RHCP?
Jordan
KF5COQ
On Sun, Mar 18, 2018, 16:34 Eduardo PY2RN <py2rn@????.???> wrote:
> Hi Brian,
> Both. You are going to need to switch between RHCP and LHCP often during a
> sat pass. The same happens if using linear polarization (V/H) but in this
> case the switch between V and H will happen much more often than in CP.
> 73
> Ed
> PY2RN
>
> From: Brian via AMSAT-BB <amsat-bb@?????.???>
> To: "amsat-bb@?????.???? <amsat-bb@?????.???>
> Sent: Sunday, March 18, 2018 6:21 PM
> Subject: [amsat-bb] Antenna Polarization Question
>
>
>
> Should I be using LHCP or RHCP when setting up the 2 meter and 440 yagi's
> to work the LEO's.
>
> Thank you
>
> Brian, KG8CO
>
> _______________________________________________
> 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: 5
Date: Mon, 19 Mar 2018 21:57:25 +0400
From: Jean Marc Momple <jean.marc.momple@?????.???>
To: Franklin Antonio <antonio@???.????????.???>
Cc: "amsat-bb@?????.???? <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Antenna Polarization Question
Message-ID: <82370B80-F48F-412F-94E2-B2B743704544@?????.???>
Content-Type: text/plain; charset=us-ascii
Guys,
Long debate for not much. I have followed this stream and believe that I
need to intervene.
It is very simple, most HAM birds does spin (sometimes a lot) and there is
no way one can anticipate as different from one bird to others. It is just
operator skills (on the spot) to determine/switch from LHCP or RCCP based on
what is the best received signal strength. It works both on the Uplink and
Downlink. There is no miracle formulae and it is a just operator skills as
mentioned before.
For commercial birds it is totally different game and should not be compared
with our humble Ham birds, they have much more means to do things that we
cannot afford to do, except if all HAM worldwide donate to AMSAT, say $10 we
then may be able to match some of the features commercially available.
Just a suggestion and food for thought.
73
Jean Marc (3B8DU)
> On Mar 19, 2018, at 8:54 PM, Franklin Antonio <antonio@???.????????.???>
wrote:
>
> When you say a satellite "has" RHCP, we have to be careful that we're
communicating clearly about what "has" means. Every satellite "has" both,
by virtue of he way antennas work.
>
> I suspect that you mean that the satellite has an antenna which transmits
RHCP in its main lobe. It is important to realize that the signal from such
an antenna is only RHCP in its main lobe. The sidelobes are gonna be LHCP.
In between, you can get anything in between. So if a satellite is oriented
so that its antenna points right at you, and they designed it to be RHCP,
then that's what you're gonna get, but if it is pointing off to the side,
then you get something else.
>
> This means that there are situations in which you might get a stronger
received signal if you switch to LHCP, or maybe even to linear. In the
commercial satellite biz, they design satellites so that their antennas
point at the users. Hams build cheaper satellites, which typically don't
have sophisticated attitude control, so sometimes they point away from you.
Also, hams try to use the things even when conditions aren't the best. If
that's your aim, then most folks have found that polarization switching
sometimes helps.
>
> ________________________________________
> From: AMSAT-BB <amsat-bb-bounces@?????.???> on behalf of Jordan Trewitt
<jmtrewitt@?????.???>
> Sent: Sunday, March 18, 2018 2:43 PM
> To: Eduardo PY2RN
> Cc: amsat-bb@?????.???
> Subject: Re: [amsat-bb] Antenna Polarization Question
>
> Maybe I'm not understanding it, but why does one need to switch between
> both, unless a particular satellite has LHCP or RHCP?
> Jordan
> KF5COQ
>
> On Sun, Mar 18, 2018, 16:34 Eduardo PY2RN <py2rn@????.???> wrote:
>
>> Hi Brian,
>> Both. You are going to need to switch between RHCP and LHCP often during a
>> sat pass. The same happens if using linear polarization (V/H) but in this
>> case the switch between V and H will happen much more often than in CP.
>> 73
>> Ed
>> PY2RN
>>
>> From: Brian via AMSAT-BB <amsat-bb@?????.???>
>> To: "amsat-bb@?????.???? <amsat-bb@?????.???>
>> Sent: Sunday, March 18, 2018 6:21 PM
>> Subject: [amsat-bb] Antenna Polarization Question
>>
>>
>>
>> Should I be using LHCP or RHCP when setting up the 2 meter and 440 yagi's
>> to work the LEO's.
>>
>> Thank you
>>
>> Brian, KG8CO
>>
>> _______________________________________________
>> 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
------------------------------
Message: 6
Date: Mon, 19 Mar 2018 16:57:29 +0000 (UTC)
From: Mr B r a d <jhill_81@?????.???>
To: amsat-bb@?????.???
Subject: [amsat-bb] weekly nets / live chat ?
Message-ID: <279792016.3347530.1521478649496@????.?????.???>
Content-Type: text/plain; charset=UTF-8
-=-=-=-=-=-=-=-=-=-
"""?Patrick WD9EWK/VA7EWK"? .....from the last dispatch of messages
....Re:??trying to get?back to the Sunday evening AMSAT roundtable """"
I Guess that is on d-star ?? this would be great to listen in on from a new
Op perspective .....
I have been looking for a Sat IRC or Sat-Op chat room or something like?
"ping jockey" toget get some quick answers to operating questions and line
up some QSO's?and have not found anything for this. even a HF or echo-link
net could be helpful.this could also solve the ' no one else was on the
bird' problem.
sticking my neck out here , but I could host it on my valleymedia.org domain
withone of the free chat room scripts if nothing more official?or better is
out here or offered?
one link on the 'easy sats' / work-sats?page would fuel the live sat-chat
room very nicely
new guy Ko6kLBrad
-=-=-=-=-=-=-=-=-=-=-
?
------------------------------
Message: 7
Date: Mon, 19 Mar 2018 14:33:29 -0400
From: Burns Fisher <burns@??????.??>
To: Jean Marc Momple <jean.marc.momple@?????.???>
Cc: "amsat-bb@?????.???? <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Antenna Polarization Question
Message-ID:
<CABX7KxUm=2QwTmVfimecvvuugeXjY_m7+W6t8rnsCrHCa7uoiQ@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
I'd really like to understand this better, but it is still not making sense
to me. I believe that if you are transmitting with a CP antenna, the E and
M waves actually go through an entire circle in one carrier cycle and a CP
antenna is able to "follow" that. Surely a satellite is not spinning at
anywhere close to 145 or 450 million revs per second, so I don't get
"spinning satellite" as an explanation for why an LHP or RHP antenna might
work better at different times.
What I do get is that a CP antenna can receive linearly polarized waves at
any angle equally. But this should be true whether the antenna is LHP or
RHP, and I would not think which direction should matter if the signal is
linear in the first place, even if the signal is spinning slowly.
That all said, I have definitely heard people say that they can get better
reception by changing from LHP to RHP. I'm not saying this is not true.
Just that I don't understand it.
73,
Burns WB1FJ
On Mon, Mar 19, 2018 at 1:57 PM, Jean Marc Momple <
jean.marc.momple@?????.???> wrote:
> Guys,
>
> Long debate for not much. I have followed this stream and believe that I
> need to intervene.
>
> It is very simple, most HAM birds does spin (sometimes a lot) and there is
> no way one can anticipate as different from one bird to others. It is just
> operator skills (on the spot) to determine/switch from LHCP or RCCP based
> on what is the best received signal strength. It works both on the Uplink
> and Downlink. There is no miracle formulae and it is a just operator skills
> as mentioned before.
>
> For commercial birds it is totally different game and should not be
> compared with our humble Ham birds, they have much more means to do things
> that we cannot afford to do, except if all HAM worldwide donate to AMSAT,
> say $10 we then may be able to match some of the features commercially
> available.
>
> Just a suggestion and food for thought.
>
>
> 73
>
>
> Jean Marc (3B8DU)
>
>
> > On Mar 19, 2018, at 8:54 PM, Franklin Antonio <antonio@???.????????.???>
> wrote:
> >
> > When you say a satellite "has" RHCP, we have to be careful that we're
> communicating clearly about what "has" means. Every satellite "has" both,
> by virtue of he way antennas work.
> >
> > I suspect that you mean that the satellite has an antenna which
> transmits RHCP in its main lobe. It is important to realize that the
> signal from such an antenna is only RHCP in its main lobe. The sidelobes
> are gonna be LHCP. In between, you can get anything in between. So if a
> satellite is oriented so that its antenna points right at you, and they
> designed it to be RHCP, then that's what you're gonna get, but if it is
> pointing off to the side, then you get something else.
> >
> > This means that there are situations in which you might get a stronger
> received signal if you switch to LHCP, or maybe even to linear. In the
> commercial satellite biz, they design satellites so that their antennas
> point at the users. Hams build cheaper satellites, which typically don't
> have sophisticated attitude control, so sometimes they point away from
> you. Also, hams try to use the things even when conditions aren't the
> best. If that's your aim, then most folks have found that polarization
> switching sometimes helps.
> >
> > ________________________________________
> > From: AMSAT-BB <amsat-bb-bounces@?????.???> on behalf of Jordan Trewitt
> <jmtrewitt@?????.???>
> > Sent: Sunday, March 18, 2018 2:43 PM
> > To: Eduardo PY2RN
> > Cc: amsat-bb@?????.???
> > Subject: Re: [amsat-bb] Antenna Polarization Question
> >
> > Maybe I'm not understanding it, but why does one need to switch between
> > both, unless a particular satellite has LHCP or RHCP?
> > Jordan
> > KF5COQ
> >
> > On Sun, Mar 18, 2018, 16:34 Eduardo PY2RN <py2rn@????.???> wrote:
> >
> >> Hi Brian,
> >> Both. You are going to need to switch between RHCP and LHCP often
> during a
> >> sat pass. The same happens if using linear polarization (V/H) but in
> this
> >> case the switch between V and H will happen much more often than in CP.
> >> 73
> >> Ed
> >> PY2RN
> >>
> >> From: Brian via AMSAT-BB <amsat-bb@?????.???>
> >> To: "amsat-bb@?????.???? <amsat-bb@?????.???>
> >> Sent: Sunday, March 18, 2018 6:21 PM
> >> Subject: [amsat-bb] Antenna Polarization Question
> >>
> >>
> >>
> >> Should I be using LHCP or RHCP when setting up the 2 meter and 440
> yagi's
> >> to work the LEO's.
> >>
> >> Thank you
> >>
> >> Brian, KG8CO
> >>
> >> _______________________________________________
> >> 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
>
> _______________________________________________
> 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: 8
Date: Mon, 19 Mar 2018 14:37:30 -0400
From: Dave Taylor <ariss.w8aas@?????.???>
To: Mr B r a d <jhill_81@?????.???>
Cc: AMSAT-BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] weekly nets / live chat ?
Message-ID: <AF2F933E-A348-4246-9D0D-7A4A33AD6CBB@?????.???>
Content-Type: text/plain; charset=us-ascii
There is a weekly AMSAT net on 14.282 MHz Sundays at 1900 UTC. Most AMSAT
chat seems to take place on this mailing list, with Facebook and Twitter
getting a lot of the time-sensitive comms.
Dave, W8AAS
> On Mar 19, 2018, at 12:57 PM, Mr B r a d via AMSAT-BB <amsat-bb@?????.???>
wrote:
>
> -=-=-=-=-=-=-=-=-=-
> """ Patrick WD9EWK/VA7EWK" .....from the last dispatch of messages
....Re: trying to get back to the Sunday evening AMSAT roundtable """"
> I Guess that is on d-star ?? this would be great to listen in on from a
new Op perspective .....
> I have been looking for a Sat IRC or Sat-Op chat room or something like
"ping jockey" toget get some quick answers to operating questions and line
up some QSO's and have not found anything for this. even a HF or echo-link
net could be helpful.this could also solve the ' no one else was on the
bird' problem.
> sticking my neck out here , but I could host it on my valleymedia.org
domain withone of the free chat room scripts if nothing more official or
better is out here or offered?
> one link on the 'easy sats' / work-sats page would fuel the live sat-chat
room very nicely
>
> new guy Ko6kLBrad
> -=-=-=-=-=-=-=-=-=-=-
>
>
>
>
>
>
>
>
>
>
> _______________________________________________
> 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: 9
Date: Mon, 19 Mar 2018 22:58:10 +0400
From: Jean Marc Momple <jean.marc.momple@?????.???>
To: Burns Fisher <burns@??????.??>
Cc: "amsat-bb@?????.???? <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Antenna Polarization Question
Message-ID: <93CBE2B9-3FC2-4E21-B7BC-8A351EDBADAE@?????.???>
Content-Type: text/plain; charset=utf-8
Try it!
Then it would be clearer to you, practice is just an extension of theory (or
vice-versa). Hi!
In our case there many unknown variable that there is no ?thumb rule?, it
depends obviously on what the birds are doing up there.
73
Jean Marc (3B8DU)
> On Mar 19, 2018, at 10:33 PM, Burns Fisher <burns@??????.??> wrote:
>
> I'd really like to understand this better, but it is still not making
sense to me. I believe that if you are transmitting with a CP antenna, the
E and M waves actually go through an entire circle in one carrier cycle and
a CP antenna is able to "follow" that. Surely a satellite is not spinning
at anywhere close to 145 or 450 million revs per second, so I don't get
"spinning satellite" as an explanation for why an LHP or RHP antenna might
work better at different times.
>
> What I do get is that a CP antenna can receive linearly polarized waves at
any angle equally. But this should be true whether the antenna is LHP or
RHP, and I would not think which direction should matter if the signal is
linear in the first place, even if the signal is spinning slowly.
>
> That all said, I have definitely heard people say that they can get better
reception by changing from LHP to RHP. I'm not saying this is not true.
Just that I don't understand it.
>
> 73,
>
> Burns WB1FJ
>
> On Mon, Mar 19, 2018 at 1:57 PM, Jean Marc Momple
<jean.marc.momple@?????.??? <mailto:jean.marc.momple@?????.???>> wrote:
> Guys,
>
> Long debate for not much. I have followed this stream and believe that I
need to intervene.
>
> It is very simple, most HAM birds does spin (sometimes a lot) and there is
no way one can anticipate as different from one bird to others. It is just
operator skills (on the spot) to determine/switch from LHCP or RCCP based on
what is the best received signal strength. It works both on the Uplink and
Downlink. There is no miracle formulae and it is a just operator skills as
mentioned before.
>
> For commercial birds it is totally different game and should not be
compared with our humble Ham birds, they have much more means to do things
that we cannot afford to do, except if all HAM worldwide donate to AMSAT,
say $10 we then may be able to match some of the features commercially
available.
>
> Just a suggestion and food for thought.
>
>
> 73
>
>
> Jean Marc (3B8DU)
>
>
> > On Mar 19, 2018, at 8:54 PM, Franklin Antonio <antonio@???.????????.???
<mailto:antonio@???.????????.???>> wrote:
> >
> > When you say a satellite "has" RHCP, we have to be careful that we're
communicating clearly about what "has" means. Every satellite "has" both,
by virtue of he way antennas work.
> >
> > I suspect that you mean that the satellite has an antenna which
transmits RHCP in its main lobe. It is important to realize that the signal
from such an antenna is only RHCP in its main lobe. The sidelobes are gonna
be LHCP. In between, you can get anything in between. So if a satellite is
oriented so that its antenna points right at you, and they designed it to be
RHCP, then that's what you're gonna get, but if it is pointing off to the
side, then you get something else.
> >
> > This means that there are situations in which you might get a stronger
received signal if you switch to LHCP, or maybe even to linear. In the
commercial satellite biz, they design satellites so that their antennas
point at the users. Hams build cheaper satellites, which typically don't
have sophisticated attitude control, so sometimes they point away from you.
Also, hams try to use the things even when conditions aren't the best. If
that's your aim, then most folks have found that polarization switching
sometimes helps.
> >
> > ________________________________________
> > From: AMSAT-BB <amsat-bb-bounces@?????.???
<mailto:amsat-bb-bounces@?????.???>> on behalf of Jordan Trewitt
<jmtrewitt@?????.??? <mailto:jmtrewitt@?????.???>>
> > Sent: Sunday, March 18, 2018 2:43 PM
> > To: Eduardo PY2RN
> > Cc: amsat-bb@?????.??? <mailto:amsat-bb@?????.???>
> > Subject: Re: [amsat-bb] Antenna Polarization Question
> >
> > Maybe I'm not understanding it, but why does one need to switch between
> > both, unless a particular satellite has LHCP or RHCP?
> > Jordan
> > KF5COQ
> >
> > On Sun, Mar 18, 2018, 16:34 Eduardo PY2RN <py2rn@????.???
<mailto:py2rn@????.???>> wrote:
> >
> >> Hi Brian,
> >> Both. You are going to need to switch between RHCP and LHCP often
during a
> >> sat pass. The same happens if using linear polarization (V/H) but in this
> >> case the switch between V and H will happen much more often than in CP.
> >> 73
> >> Ed
> >> PY2RN
> >>
> >> From: Brian via AMSAT-BB <amsat-bb@?????.???
<mailto:amsat-bb@?????.???>>
> >> To: "amsat-bb@?????.??? <mailto:amsat-bb@?????.???>"
<amsat-bb@?????.??? <mailto:amsat-bb@?????.???>>
> >> Sent: Sunday, March 18, 2018 6:21 PM
> >> Subject: [amsat-bb] Antenna Polarization Question
> >>
> >>
> >>
> >> Should I be using LHCP or RHCP when setting up the 2 meter and 440 yagi's
> >> to work the LEO's.
> >>
> >> Thank you
> >>
> >> Brian, KG8CO
> >>
> >> _______________________________________________
> >> Sent via AMSAT-BB@?????.??? <mailto: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
<http://www.amsat.org/mailman/listinfo/amsat-bb>
> >>
> >>
> >>
> >> _______________________________________________
> >> Sent via AMSAT-BB@?????.??? <mailto: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
<http://www.amsat.org/mailman/listinfo/amsat-bb>
> >>
> > _______________________________________________
> > Sent via AMSAT-BB@?????.??? <mailto: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
<http://www.amsat.org/mailman/listinfo/amsat-bb>
> > _______________________________________________
> > Sent via AMSAT-BB@?????.??? <mailto: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
<http://www.amsat.org/mailman/listinfo/amsat-bb>
>
> _______________________________________________
> Sent via AMSAT-BB@?????.??? <mailto: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
<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!
http://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
End of AMSAT-BB Digest, Vol 13, Issue 107
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