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CX2SA > SATDIG 05.06.19 20:15l 891 Lines 26659 Bytes #999 (0) @ WW
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Sent: 190605/1807Z @:CX2SA.SAL.URY.SOAM #:7436 [Salto] FBB7.00e $:AMSATBB14216
From: CX2SA@CX2SA.SAL.URY.SOAM
To : SATDIG@WW
Today's Topics:
1. XW2D satellite problem (alex weimer)
2. Re: XW2D satellite problem? (Robert Bruninga)
3. Re: 23cm antenna for L/V (Ronald G. Parsons)
4. Re: XW2D satellite problem? (Glenn Miller - AA5PK)
5. Re: XW2D satellite problem? (Scott)
6. Re: XW2D satellite problem? (Lapo Pieri)
7. Re: XW2D satellite problem (Alan Kung)
8. Re: XW2D satellite problem (alex weimer)
9. satpc32 V. 12.8d (73 Bob W7LRD)
10. Doppler shift question (Philip Jenkins)
11. Re: Doppler shift question (Paul Stoetzer)
12. Upcoming ARISS Contact Schedule as of 2019-06-05 18:00 UTC
(aj9n@???.????
13. Re: Doppler shift question (Dave Taylor)
----------------------------------------------------------------------
Message: 1
Date: Wed, 5 Jun 2019 10:12:57 -0400 (EDT)
From: alex weimer <ingejack@???.???>
To: amsat-bb@?????.???
Subject: [amsat-bb] XW2D satellite problem
Message-ID: <1290013158.2354.1559743977908@???????.???.???>
Content-Type: text/plain; charset=UTF-8
I was on XW2D at1401 utc pass and experienced extreme intermittent signals
on the downlink ! Every few seconds I could hear myself , then would be cut
off in mid sentence. K9VSW was also on but had the same problem. I would
hear his signal , then he would be cut off as well. Signal when present was
strong but there is a definite problem in the satellite JACK KC7MG
------------------------------
Message: 2
Date: Wed, 5 Jun 2019 10:17:49 -0400
From: Robert Bruninga <bruninga@????.???>
To: AMSAT-BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] XW2D satellite problem?
Message-ID: <e03353e160ded1831ee90afcd5002236@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Or could it be a problem on the ground somewhere in the footprint
de-sensing the satellite receiver?
Bob
-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces@?????.???> On Behalf Of alex weimer via
AMSAT-BB
Sent: Wednesday, June 5, 2019 10:13 AM
To: amsat-bb@?????.???
Subject: [amsat-bb] XW2D satellite problem
I was on XW2D at1401 utc pass and experienced extreme intermittent signals
on the downlink ! Every few seconds I could hear myself , then would be
cut off in mid sentence. K9VSW was also on but had the same problem. I
would hear his signal , then he would be cut off as well. Signal when
present was strong but there is a definite problem in the satellite JACK
KC7MG _______________________________________________
------------------------------
Message: 3
Date: Wed, 5 Jun 2019 09:32:16 -0500
From: "Ronald G. Parsons" <w5rkn@?????.???>
To: "AMSAT-BB" <AMSAT-BB@?????.???>
Subject: Re: [amsat-bb] 23cm antenna for L/V
Message-ID: <F4DEDF2854A24CE5A5B08DD6625CA1E5@?????????>
Content-Type: text/plain; charset="utf-8"
I?ve been using the M2 Antenna model 23CM22EZA with good success. It has a
70? boom and is rear mounted. Very easy assembly.
Ron W5RKN
------------------------------
Message: 4
Date: Wed, 5 Jun 2019 09:38:22 -0500
From: "Glenn Miller - AA5PK" <aa5pk@??????????.???>
To: "Robert Bruninga" <bruninga@????.???>, "AMSAT-BB"
<amsat-bb@?????.???>
Subject: Re: [amsat-bb] XW2D satellite problem?
Message-ID: <2031EFFCB7174B47A3B275ACEA8CCEFA@??????????????>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
The CW beacon is sending an intermittent solid tone lasting 2-3 seconds.
The transponder is active during the same time the
tone is present.
Glenn
-----Original Message-----
From: Robert Bruninga via AMSAT-BB
Sent: Wednesday, June 5, 2019 9:17 AM
To: AMSAT-BB
Subject: Re: [amsat-bb] XW2D satellite problem?
Or could it be a problem on the ground somewhere in the footprint
de-sensing the satellite receiver?
Bob
-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces@?????.???> On Behalf Of alex weimer via
AMSAT-BB
Sent: Wednesday, June 5, 2019 10:13 AM
To: amsat-bb@?????.???
Subject: [amsat-bb] XW2D satellite problem
I was on XW2D at1401 utc pass and experienced extreme intermittent signals
on the downlink ! Every few seconds I could hear myself , then would be
cut off in mid sentence. K9VSW was also on but had the same problem. I
would hear his signal , then he would be cut off as well. Signal when
present was strong but there is a definite problem in the satellite JACK
KC7MG _______________________________________________
_______________________________________________
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: https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 5
Date: Wed, 5 Jun 2019 11:01:42 -0400
From: "Scott" <scott23192@?????.???>
To: "AMSAT-BB" <amsat-bb@?????.???>
Subject: Re: [amsat-bb] XW2D satellite problem?
Message-ID: <81BC405E9C484DEB8EB3FDACE3E2EC9D@???????>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
My observations have been the same. Looking at the entire downlink passband
on an SDR waterfall, I would see others at their spots on the transponder
while I would be working through some other unused frequency.
We would all be good for a couple of seconds and then all drop to zero
downlink at the same time. The effect was the same whether transmitting SSB
or CW.
-Scott, K4KDR
=====================================
-----Original Message-----
From: Glenn Miller - AA5PK via AMSAT-BB
Sent: Wednesday, June 05, 2019 10:38 AM
To: Robert Bruninga ; AMSAT-BB
Subject: Re: [amsat-bb] XW2D satellite problem?
The CW beacon is sending an intermittent solid tone lasting 2-3 seconds.
The transponder is active during the same time the
tone is present.
Glenn
-----Original Message-----
From: Robert Bruninga via AMSAT-BB
Sent: Wednesday, June 5, 2019 9:17 AM
To: AMSAT-BB
Subject: Re: [amsat-bb] XW2D satellite problem?
Or could it be a problem on the ground somewhere in the footprint
de-sensing the satellite receiver?
Bob
-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces@?????.???> On Behalf Of alex weimer via
AMSAT-BB
Sent: Wednesday, June 5, 2019 10:13 AM
To: amsat-bb@?????.???
Subject: [amsat-bb] XW2D satellite problem
I was on XW2D at1401 utc pass and experienced extreme intermittent signals
on the downlink ! Every few seconds I could hear myself , then would be
cut off in mid sentence. K9VSW was also on but had the same problem. I
would hear his signal , then he would be cut off as well. Signal when
present was strong but there is a definite problem in the satellite JACK
KC7MG _______________________________________________
------------------------------
Message: 6
Date: Wed, 5 Jun 2019 17:30:18 +0200
From: Lapo Pieri <ik5nax@???????????.??>
To: AMSAT-BB <AMSAT-BB@?????.???>
Subject: Re: [amsat-bb] XW2D satellite problem?
Message-ID: <20190605153018.GD2483@??????>
Content-Type: text/plain; charset=us-ascii
11:01 Wed 05 Jun 19 , Scott via AMSAT-BB wrote:
>...
Trasponder not operating for me at 15:10Z over Europe; heard beacon
with ~2s key down repeating on a ~8s period, no more, no CW.
Lapo, IK5NAX
------------------------------
Message: 7
Date: Thu, 6 Jun 2019 00:12:47 +0800 (CST)
From: "Alan Kung" <camsat@???.???.???>
To: "alex weimer" <ingejack@???.???>
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] XW2D satellite problem
Message-ID: <72d6b0b.5e1b3d.16b286a0e36.Coremail.camsat@???.???.???>
Content-Type: text/plain; charset=GBK
Hi Jack,
Do you have any XW2D telemetry data recorded at that time? It would be
appreciated if you can send it to me. BTW. XW2D''s OBC will be automatically
reset every 48 hours.
73
Alan, BA1DU
--
??VIP????????????????????????????????????????????????????????????????????????
Alert message of Netease Vipmail?Never provide your password, security
questions, verification codes, or any other personal important information
details to anyone else.
You can identify mail message by telephone,video-chat or other ways.You
should make sure that your email address, bank account and other
confidential information as secure as possible. Thank you for keeping your
email account secure.
At 2019-06-05 22:12:57, "alex weimer via AMSAT-BB" <amsat-bb@?????.???> wrote:
>I was on XW2D at1401 utc pass and experienced extreme intermittent signals
on the downlink ! Every few seconds I could hear myself , then would be cut
off in mid sentence. K9VSW was also on but had the same problem. I would
hear his signal , then he would be cut off as well. Signal when present was
strong but there is a definite problem in the satellite JACK KC7MG
>_______________________________________________
>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: https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 8
Date: Wed, 5 Jun 2019 12:31:49 -0400 (EDT)
From: alex weimer <ingejack@???.???>
To: Alan Kung <camsat@???.???.???>
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] XW2D satellite problem
Message-ID: <91622022.5412.1559752309266@???????.???.???>
Content-Type: text/plain; charset=UTF-8
No sorry did not record that pass !!!
> On June 5, 2019 at 12:12 PM Alan Kung <camsat@???.???.???> wrote:
>
> Hi Jack,
> Do you have any XW2D telemetry data recorded at that time? It would be
appreciated if you can send it to me. BTW. XW2D''s OBC will be automatically
reset every 48 hours.
>
> 73
> Alan, BA1DU
> --
>
> ---------------------------------------------
>
??VIP????????????????????????????????????????????????????????????????????????
> Alert message of Netease Vipmail?Never provide your password, security
questions, verification codes, or any other personal important information
details to anyone else.
> You can identify mail message by telephone,video-chat or other
ways.You should make sure that your email address, bank account and other
confidential information as secure as possible. Thank you for keeping your
email account secure.
>
>
>
> At 2019-06-05 22:12:57, "alex weimer via AMSAT-BB"
<amsat-bb@?????.???> wrote:
> >I was on XW2D at1401 utc pass and experienced extreme intermittent
signals on the downlink ! Every few seconds I could hear myself , then would
be cut off in mid sentence. K9VSW was also on but had the same problem. I
would hear his signal , then he would be cut off as well. Signal when
present was strong but there is a definite problem in the satellite JACK
KC7MG
> >_______________________________________________
> >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: https://www.amsat.org/mailman/listinfo/amsat-bb
>
------------------------------
Message: 9
Date: Wed, 5 Jun 2019 10:23:08 -0700 (PDT)
From: 73 Bob W7LRD <w7lrd@???????.???>
To: amsat-bb <amsat-bb@?????.???>
Subject: [amsat-bb] satpc32 V. 12.8d
Message-ID: <997721517.303450.1559755389095@???????.???????.???>
Content-Type: text/plain; charset=UTF-8
Setting up satpc32 on a new computer. Where is the "setup" button?
73 Bob W7LRD
------------------------------
Message: 10
Date: Wed, 5 Jun 2019 13:41:49 -0400
From: Philip Jenkins <n4hf.philip@?????.???>
To: AMSAT BB <amsat-bb@?????.???>
Subject: [amsat-bb] Doppler shift question
Message-ID:
<CAGdEbNZy_J5K7W_H0tkDgLguu1TNtfbrd8zKqqDAWWWfWZw+7Q@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
This came up at AMSAT Academy at Hamvention, and I still can't wrap my head
around it (something simple I'm not getting, I'm sure). I know the
xmit/receive frequencies aren't shifted, stay the same at the satellite.
SO-50 has a 435 Mhz downlink; as the satellite approaches me from AOS I
lower my receive frequency (and continue lowering it as the bird approaches
LOS). So far so good.
AO 91/92 have a 435 Mhz uplink,; as the satellite approaches me from AOS, I
go up in my transmit frequency.
Here is where I get lost: Why do I* lower* the frequency on 435 Mhz when
receiving a satellite, but *raise* the 435 Mhz frequency when transmitting
to a satelllite?
So, my question boils down to - why should transmit doppler shift go in the
opposite direction from receive on the same band? In both cases, the
satellites are approaching me (from AOS).
Basically, why the difference when I'm transmitting and when I'm
receiving?
73
Philip N4HF
------------------------------
Message: 11
Date: Wed, 5 Jun 2019 13:54:13 -0400
From: Paul Stoetzer <n8hm@????.???>
To: Philip Jenkins <n4hf.philip@?????.???>
Cc: AMSAT BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Doppler shift question
Message-ID:
<CABzOSOoj43wRPxb3M08r9H71hbmoOtjB3vsZrWiPZeb99dWuxw@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
When you're on the ground listening to SO-50 as it approaches you, the
RF waves are compressed, and thus the frequency you receive at is
higher than the frequency the satellite is transmitting at.
When you're transmitting to AO-91 as it approaches you, you need to
compensate for the fact that your RF waves are going to be compressed
and appear at the satellite at a higher frequency than you are
transmitting at. So you have to transmit lower than the nominal
frequency.
73,
Paul, N8HM
On Wed, Jun 5, 2019 at 1:45 PM Philip Jenkins via AMSAT-BB
<amsat-bb@?????.???> wrote:
>
> This came up at AMSAT Academy at Hamvention, and I still can't wrap my head
> around it (something simple I'm not getting, I'm sure). I know the
> xmit/receive frequencies aren't shifted, stay the same at the satellite.
>
> SO-50 has a 435 Mhz downlink; as the satellite approaches me from AOS I
> lower my receive frequency (and continue lowering it as the bird approaches
> LOS). So far so good.
>
> AO 91/92 have a 435 Mhz uplink,; as the satellite approaches me from AOS, I
> go up in my transmit frequency.
>
> Here is where I get lost: Why do I* lower* the frequency on 435 Mhz when
> receiving a satellite, but *raise* the 435 Mhz frequency when transmitting
> to a satelllite?
>
> So, my question boils down to - why should transmit doppler shift go in the
> opposite direction from receive on the same band? In both cases, the
> satellites are approaching me (from AOS).
>
> Basically, why the difference when I'm transmitting and when I'm
> receiving?
>
> 73
>
> Philip N4HF
> _______________________________________________
> 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: https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
Message: 12
Date: Wed, 5 Jun 2019 17:54:47 +0000 (UTC)
From: aj9n@???.???
To: amsat-bb@?????.???
Subject: [amsat-bb] Upcoming ARISS Contact Schedule as of 2019-06-05
18:00 UTC
Message-ID: <1940360639.383782.1559757287977@????.?????.???>
Content-Type: text/plain; charset=UTF-8
Upcoming ARISS Contact Schedule as of 2019-06-05 18:00 UTC
Quick list of scheduled contacts and events:
Moriah Central School, Port Henry, NY, telebridge via VK6MJ
The ISS callsign is presently scheduled to be OR4ISS
The scheduled astronaut is David St-Jacques KG5FYI (***)
Contact is go for Option #13: Thu 2019-06-06 16:54:12 UTC 71 deg
?
?
Amur State University, Blagoveshchensk, Russia, direct via TBD
The ISS callsign is presently scheduled to be RS?ISS
The scheduled astronaut is Aleksey Ovchinin
Contact is a go for Wed 2019-06-05 07:50 UTC
?
D?m d?t? a ml?de?e Olomouc (House of Children and Youth Olomouc), Olomouc,
Czech Republic, direct via OK2KWX
The ISS callsign is presently scheduled to be OR4ISS
The scheduled astronaut is Nick Hague KG5TMV
Contact is go for: Sat 2019-06-08 13:05:59 UTC 90 deg
?
Peninsula Grammar, Melbourne, Australia, telebridge via VK4KHZ
The ISS callsign is presently scheduled to be NA1SS
The scheduled astronaut is Nick Hague KG5TMV
Contact is go for: Thu 2019-06-13 11:10:52 UTC 79 deg
?
Smithsonian Air and Space ? Udvar-Hazy, Chantilly, VA, USA, telebridge via
W6SRJ
The ISS callsign is presently scheduled to be NA1SS
The scheduled astronaut is Nick Hague KG5TMV (***)
Contact is go for: Sat 2019-06-15 18:11:51 UTC 42 deg
?
Watch for these upcoming events:?
MAI-75 SSTV Event:? Wed 2019-06-05 12:00 UTC to 16:00 UTC
MAI-75 SSTV Event:? Thu 2019-06-06 11:30 UTC to 15:30 UTC
?
?
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?2019-06-05 18:00 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
http://www.amsat.org/amsat/ariss/news/arissnews.txt
?
The successful school list has been updated as of 2019-05-28 21:00 UTC.
http://www.amsat.org/amsat/ariss/news/Successful_ARISS_schools.rtf
?
?
The ARISS webpage is at http://www.ariss.org/??
Note that there are links to other ARISS websites from this site.
The main page for Applying to Host a Scheduled Contact may be found at
http://www.ariss.org/apply-to-host-an-ariss-contact.html??
ARISS Contact Applications (United States)
?
The ARISS webpage is at http://www.ariss.org/??
Note that there are links to other ARISS websites from this site.
******************************************************************************
******************************************************************************
****************
ARISS Contact Applications (Europe, Africa and the Middle East)
?
Schools and Youth organizations in Europe, Africa and the Middle East
interested in setting up an ARISS radio contact with an astronaut on board
the International Space Station are invited to submit an application from
September to October and from February to April.
Please refer to details and the application form at
www.ariss-eu.org/school-contacts.? Applications should be addressed by email
to:? school.selection.manager@????????.???
?
ARISS Contact Applications (Canada, Central and South America, Asia and
Australia and Russia)
?
Organizations outside the United States can apply for an ARISS contact by
filling out an application.? Please direct questions to the appropriate
regional representative listed below. If your country is not specifically
listed, send your questions to the nearest ARISS Region listed. If you are
unsure which address to use, please send your question to the ARISS-Canada
representative; they will forward your question to the appropriate
coordinator.
?
For the application, go to:? http://www.ariss.org/ariss-application.html.
ARISS-Canada and the Americas, except USA: Steve McFarlane, VE3TBD email to:
ve3tbd@?????.???
ARISS-Japan, Asia, Pacific and Australia: Satoshi Yasuda, 7M3TJZ email to:
ariss@???????.???? Japan Amateur Radio League (JARL) http://www.jarl.org/ ?
ARISS-Russia: Soyuz Radioljubitelei Rossii (SRR) https://srr.ru/?
?
?
******************************************************************************
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??
Please note that the HamTV system has been brought back to earth for
troubleshooting.? Please monitor ARISS-EU or ARISS-ON for the very latest
news on the troubleshooting efforts.?
?
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@?????????.???
The HamTV webpage:? https://www.amsat-on.be/hamtv-summary/
?
?
****************************************************************************
ARISS congratulations the following mentors who have now mentored over 100
schools:?
Satoshi 7M3TJZ with 135
Francesco IK?WGF with 132
Gaston ON4WF with 123
Sergey RV3DR 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.
Total number?of ARISS ISS to earth school events is 1312.
Each school counts as 1?event.
Total number of ARISS ISS to earth school contacts is 1255.
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:
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
****************************************************************************
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
Check out the Zoho reports of the ARISS?contacts
https://reports.zoho.com/ZDBDataSheetView.cc?DBID=412218000000020415
****************************************************************************
Exp. 58 on orbit
Oleg Konenenko
David St-Jacques KG5FYI
Anne McClain
?
Exp. 59 on orbit
Christina Koch
Aleksey Ovchinin
Nick Hague KG5TMV
****************************************************************************
73,
Charlie?Sufana AJ9N
One of the ARISS operation team mentors
?
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------------------------------
Message: 13
Date: Wed, 5 Jun 2019 13:55:19 -0400
From: Dave Taylor <w8aas@???????.???>
To: Philip Jenkins <n4hf.philip@?????.???>
Cc: AMSAT BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Doppler shift question
Message-ID: <D37672A9-AFD2-4A04-BB51-E0FF4A649E72@???????.???>
Content-Type: text/plain; charset=utf-8
Look at it from the satellite?s point of view. The satellite is receiving
your Doppler-shifted signal. If you continue transmitting on a fixed
frequency, the satellite sees the frequency dropping. To keep the frequency
seen by the satellite steady, you need to offset the drop by increasing your
transmit frequency at the same rate.
Dave, W8AAS
> On Jun 5, 2019, at 1:41 PM, Philip Jenkins via AMSAT-BB
<amsat-bb@?????.???> wrote:
>
> This came up at AMSAT Academy at Hamvention, and I still can't wrap my head
> around it (something simple I'm not getting, I'm sure). I know the
> xmit/receive frequencies aren't shifted, stay the same at the satellite.
>
> SO-50 has a 435 Mhz downlink; as the satellite approaches me from AOS I
> lower my receive frequency (and continue lowering it as the bird approaches
> LOS). So far so good.
>
> AO 91/92 have a 435 Mhz uplink,; as the satellite approaches me from AOS, I
> go up in my transmit frequency.
>
> Here is where I get lost: Why do I* lower* the frequency on 435 Mhz when
> receiving a satellite, but *raise* the 435 Mhz frequency when transmitting
> to a satelllite?
>
> So, my question boils down to - why should transmit doppler shift go in the
> opposite direction from receive on the same band? In both cases, the
> satellites are approaching me (from AOS).
>
> Basically, why the difference when I'm transmitting and when I'm
> receiving?
>
> 73
>
> Philip N4HF
> _______________________________________________
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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!
https://www.amsat.org/mailman/listinfo/amsat-bb
------------------------------
End of AMSAT-BB Digest, Vol 14, Issue 216
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