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CX2SA > SATDIG 28.11.20 02:07l 1002 Lines 29772 Bytes #999 (0) @ WW
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Sent: 201127/2337Z @:CX2SA.SAL.URY.SOAM #:44310 [Salto] FBB7.00e $:AMSATBB15445
From: CX2SA@CX2SA.SAL.URY.SOAM
To : SATDIG@WW
Today's Topics:
1. Successful PSAT SSTV and Waterfall Drawing Experiment
(Brian Wilkins KO4AQF)
2. Re: Doppler correction between AOS and LOS (Hasan N0AN)
3. Re: vertical antenna (hb9wdf@???????.???
4. APRS via sats (Armand SP3QFE)
5. Re: APRS via sats (Fabrizio Carrai)
6. Upcoming ARISS Contact Schedule as of 2020-11-27 17:30 UTC
(aj9n@???.????
7. Fiberglass Cross-boom Alternative (KENT BRITAIN)
8. Re: vertical antenna (Bob Liddy (K8BL))
----------------------------------------------------------------------
Message: 1
Date: Fri, 27 Nov 2020 08:50:57 -0500
From: Brian Wilkins KO4AQF <bwilkins@?????.???>
To: AMSAT BB <amsat-bb@?????.???>
Subject: [amsat-bb] Successful PSAT SSTV and Waterfall Drawing
Experiment
Message-ID:
<CAO_Eq32+aPs5=ffxTW5VvdCFbw6PNdythiZ3xLbWaqcXUK86Vw@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
For over a month, we have been attempting to TX and RX SSTV via PSAT2. We
discovered on Bob?s APRS page that PSAT2 can support users sending and
receiving SSTV as long as it detects PSK31 in the passband. While we were
unable to get SSTV to work via PSAT2 and experimentations are still on
going, we were able to successfully send SSTV from N8URE in Maryland to
KO4AQF in Florida. This required dozens of cases of trial and error. We
plan to publish the procedure in a future AMSAT journal article.
B/W SSTV:
https://i.imgur.com/nFG6UII.jpg
B/W was easier to decode than color.
In addition to SSTV, we discovered that PSAT will also support waterfall
drawing where the sound will draw the picture directly in the waterfall
display. This provides evidence that when PSK31 is detected that PSAT
transponder may become a bent pipe.
Waterfall picture
https://i.imgur.com/4fdvib6.png
More experimentations are planned. We attempted to send Olivia however it
was unable to be decoded. This may be due to the manual doppler being
performed and / or fade due to the satellite.
In order to send PSK31 to PSAT, we used upwards of 100-200 watts on the 10m
uplink. Downlink is UHF and must be Doppler corrected. You need a pitcher
and a catcher. In this case, the catcher was manually adjusting for Doppler
on a D72A using an Arrow antenna. Then the catcher used an iPhone Voice
Memo app to record then playback the audio. It can be decoded using fldigi
and SSTV can be decoded with your favorite sstv app.
I?d like to thank everyone who has helped us better understand and
participate along the way. Bob, Brno University, KK4YEL, KI5HHK, and N8URE
who did the heavy lifting of sending the data over the 10m uplink. Brno
University was instrumental in providing the right technical details along
with their github page for us to dial in our transmission.
More in depth technical details to follow
Signed,
N8URE
KO4AQF
KK4YEL
KI5HHK
--
Brian Wilkins
KO4AQF
------------------------------
Message: 2
Date: Fri, 27 Nov 2020 08:36:01 -0600
From: Hasan N0AN <hbasri.schiers6@?????.???>
To: "lu9cbl@?????.???? <lu9cbl@?????.???>
Cc: AMSAT BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] Doppler correction between AOS and LOS
Message-ID:
<CAM4UQf0K7ND=BRhoe1j6ANm-dYpizMRvRH9p1u-hBZXhpCRGog@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Make sure in your tracking program, you didn't accidentally enter a silly
wrong altitude value for your qth. I had an issue here, where my altitude
got changed to 30,000 meters...it caused very similar issues with doppler
tracking at various points during the pass, especially at TCA.
73, N0AN
Hasan
On Thu, Nov 26, 2020 at 6:30 PM lu9cbl--- via AMSAT-BB <amsat-bb@?????.???>
wrote:
> Hi to all, a friend of mine, has satpc32 with and SDR. We have the
> doppler correction, when the satellites it's in AOS, de frequency it's
> OK, in TCA has (for example) 1 KHz difference, and in LOS has 2 KHz
> difference.
>
> It's there any configuration to modify??? all the satellites that we
> found, in AOS has the correct frequency, but in TCA and LOS its not the
> same as we can see in the waterfall of HDSDR.
>
> Ir i compare the doppler with http://www.amsat.org.ar/pass.htm the
> frequency has the same between the waterfall and the webpage.
>
> Thanks in advance.
>
> Mati LU9CBL
>
>
> --
> El software de antivirus Avast ha analizado este correo electr?nico en
> busca de virus.
> https://www.avast.com/antivirus
>
> _______________________________________________
> 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: 3
Date: Fri, 27 Nov 2020 15:39:38 +0100 (CET)
From: "hb9wdf@???????.??? <hb9wdf@???????.??>
To: 73 Bob W7LRD <w7lrd@???????.???>
Cc: amsat-bb@?????.???
Subject: Re: [amsat-bb] vertical antenna
Message-ID: <1598555510.26078.1606487978617@???????.??>
Content-Type: text/plain; charset=UTF-8
I wrote a blogpost about vertical antennas (in german - maybe google
translate can help you). But there are some radiation patterns in the
article from different antennas. They can help you for understanding in
which situation it works also with satellite.
https://www.michi-dani.ch/2020/10/21/es-geht-auch-mit-rundstrahlenden-antennen
/
73s Michael
hb9wdf
----Urspr?ngliche Nachricht----
Von : amsat-bb@?????.???
Datum : 26/11/2020 - 23:28 (MN)
An : amsat-bb@?????.???
Betreff : [amsat-bb] vertical antenna
anyone using a vertical antenna for the FM satellites? Which one & how does
it work?
73 Bob W7LRD
_______________________________________________
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: 4
Date: Fri, 27 Nov 2020 16:02:25 +0100
From: Armand SP3QFE <kontakt@??????.???>
To: AMSAT BB <amsat-bb@?????.???>
Subject: [amsat-bb] APRS via sats
Message-ID: <a94ec6a19c87f94c221629fc046b626d@??????.???>
Content-Type: text/plain; charset=US-ASCII; format=flowed
Hello Everybody,
Today morning I run to test a new setup in JO92he for APRS via
digipeaters on satellites on 145.825MHz.
I do not control it all the time, but at ~14:35UTC I heard two not very
good quality APRS packages. I immediately checked the screen of the
radio. I saw only something like PSAT??. Both PCSAT (NO44) and PSAT2
(NO104) were far away from my location. It was about 10 minutes before
AOS for the ISS.
Where else we have APRS digipeaters on 145.825 MHz in the sky? Thank
you.
73, Armand SP3QFE
------------------------------
Message: 5
Date: Fri, 27 Nov 2020 18:03:20 +0100
From: Fabrizio Carrai <fabrizio.carrai@?????.???>
To: Armand SP3QFE <kontakt@??????.???>
Cc: AMSAT BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] APRS via sats
Message-ID:
<CAJXPg6+LLKxkmLoFjdQCSFDjo93iTX+8jhrbCbuZhOGqoMT7MQ@????.?????.???>
Content-Type: text/plain; charset="UTF-8"
Hello Armand,
these are the APRS sat digipeating on 145.825 Mhz I have on my GPredict
data set:
LAPAN-A2 (IO-86)
NO-44 (*)
NO-84
PSAT2 (NO-104)
(*) Almost no activity according to https://www.amsat.org/status/
Hope it helps
73, Fabrizio IU5GEZ
Il giorno ven 27 nov 2020 alle ore 16:05 Armand SP3QFE via AMSAT-BB <
amsat-bb@?????.???> ha scritto:
> Hello Everybody,
>
> Today morning I run to test a new setup in JO92he for APRS via
> digipeaters on satellites on 145.825MHz.
> I do not control it all the time, but at ~14:35UTC I heard two not very
> good quality APRS packages. I immediately checked the screen of the
> radio. I saw only something like PSAT??. Both PCSAT (NO44) and PSAT2
> (NO104) were far away from my location. It was about 10 minutes before
> AOS for the ISS.
>
> Where else we have APRS digipeaters on 145.825 MHz in the sky? Thank
> you.
>
> 73, Armand SP3QFE
> _______________________________________________
> 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
>
--
*Fabrizio*
------------------------------
Message: 6
Date: Fri, 27 Nov 2020 17:33:08 +0000 (UTC)
From: <aj9n@???.???>
To: amsat-bb@?????.???
Subject: [amsat-bb] Upcoming ARISS Contact Schedule as of 2020-11-27
17:30 UTC
Message-ID: <2026840393.1316484.1606498388814@????.?????.???>
Content-Type: text/plain; charset=UTF-8
Upcoming ARISS Contact Schedule as of 2020-11-27 17:30 UTC
?
Quick list of scheduled contacts and events:
?
?
Amur State University, Blagoveshchensk, Russia, direct via TBD
The ISS callsign is presently scheduled to be RS?ISS
The downlink frequency is presently scheduled to be 145.800 MHz
The latest information on the operation mode can be found at
https://www.ariss.org/current-status-of-iss-stations.html
The scheduled astronaut is Sergey Ryzhikov
Contact is go for Thu 2020-12-03 08:45 UTC
?
Scuola Secondaria di I grado ?Anna Frank?, Pistoia, Italy, telebridge via
IK1SLD
The ISS callsign is presently scheduled to be OR4ISS
The downlink frequency is presently scheduled to be 145.800 MHz
The latest information on the operation mode can be found at
https://www.ariss.org/current-status-of-iss-stations.html??
The scheduled astronaut is Victor Glover KI5BKC
Contact is go for: Fri 2020-12-04 12:25:22 UTC 50 deg
?
Tecumseh High School Electronics and Amateur Radio, Tecumseh, OK, direct via
K5THS
The ISS callsign is presently scheduled to be NA1SS
The downlink frequency is presently scheduled to be 145.800 MHz
The latest information on the operation mode can be found at
https://www.ariss.org/current-status-of-iss-stations.html?
The scheduled astronaut is Shannon Walker KD5DXB
Contact is go for: Fri 2020-12-04 18:33:30 UTC 78 deg
?
******************************************************************************
*******************************
?
The latest information on the operation mode can be found at
https://www.ariss.org/current-status-of-iss-stations.html
The latest list of frequencies in use can be found at
https://www.ariss.org/contact-the-iss.html
?
##############################################################################
##########################################################
?
A multi-point telebridge contact means that each student will be on the
telebridge from their own home.
******************************************************************************
**********************************************************
?
ARISS is very aware of the impact that COVID-19 is having on schools and the
public in general.? As such, we may have last minute cancellations or
postponements of school contacts.? As always, I will try to provide everyone
with near-real-time updates. Watch for future COVID-19 related announcements
at https://www.ariss.org/
?
The following schools have now been postponed or cancelled due to COVID-19:?
?
Postponed:
No new schools
?
Cancelled:
No new schools
?
******************************************************************************
**********************************************************
?
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?2020-11-26 05:00 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.
?
https://www.amsat.org/amsat/ariss/news/arissnews.rtf
https://www.amsat.org/amsat/ariss/news/arissnews.txt
?
?
The successful school list has been updated as of 2020-10-14 18:00 UTC.
https://www.amsat.org/amsat/ariss/news/Successful_ARISS_schools.rtf
?
?
?
The ARISS webpage is at https://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
https://www.ariss.org/apply-to-host-an-ariss-contact.html ???
?
?
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
?
ARISS Contact Applications (United States)
?
The Amateur Radio on the International Space Station (ARISS) Program is
seeking formal and informal education institutions and organizations,
individually or working together, to host an Amateur Radio contact with a
crew member on board the ISS. ARISS anticipates that the contact would be
held between July 1, 2021 and December 30,
2021. Crew scheduling and ISS orbits will determine the exact contact dates.
To maximize these radio contact opportunities, ARISS is looking for
organizations that will draw large numbers of participants and integrate the
contact into a well-developed education plan.
?
The deadline to submit a proposal is November 24th, 2020. Proposal
information and more details such as expectations, proposal guidelines and
the proposal form can be found at www.ariss.org. An ARISS Introductory
Webinar session will be held on October 8, 2020 at 8PM ET. The Eventbrite
link to sign up is: https://ariss-proposal-webinar-fall-2020.eventbrite.com
?
The Opportunity
?
Crew members aboard the International Space Station will participate in
scheduled Amateur Radio contacts. These radio contacts are approximately 10
minutes in length and allow students to interact with the astronauts through
a question-and-answer session.
?
An ARISS contact is a voice-only communication opportunity via Amateur Radio
between astronauts and cosmonauts aboard the space station and classrooms
and communities. ARISS contacts afford education audiences the opportunity
to learn firsthand from astronauts what it is like to live and work in space
and to learn about space research conducted on the ISS. Students also will
have an opportunity to learn about satellite communication, wireless
technology, and radio science.
?
Because of the nature of human spaceflight and the complexity of scheduling
activities aboard the ISS, organizations must demonstrate flexibility to
accommodate changes in dates and times of the radio contact.
?
Amateur Radio organizations around the world with the support of NASA and
space agencies in Russia, Canada, Japan and Europe present educational
organizations with this opportunity. The ham radio organizations? volunteer
efforts provide the equipment and operational support to enable
communication between crew on the ISS and students
around the world using Amateur Radio.
?
Please direct any questions to?ariss.us.education@?????.???.
?
For future proposal information and more details such as expectations,
proposal guidelines and proposal form, and dates and times of Information
Webinars, go to www.ariss.org.
?
About ARISS:
?
Amateur Radio on the International Space Station (ARISS) is a cooperative
venture of international amateur radio societies and the space agencies that
support the International Space Station (ISS).? In the United States,
sponsors are the Radio Amateur Satellite Corporation (AMSAT), the American
Radio Relay League (ARRL), the ISS National Lab and National Aeronautics and
Space Administration (NASA). The primary goal of ARISS is to promote
exploration of science, technology, engineering, and mathematics (STEAM)
topics by organizing scheduled contacts via amateur radio between crew
members aboard the ISS and students in classrooms or public forms. Before
and during these radio contacts, students, educators, parents, and
communities learn about space, space technologies, and amateur radio. For
more information, see www.ariss.org.
?
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
?
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:? https://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) https://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 unless otherwise noted.
?
******************************************************************************
*
?
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 https://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:
?
Francesco IK?WGF with 140
Satoshi 7M3TJZ with 138
Sergey RV3DR with 137
Gaston ON4WF with 123
?
****************************************************************************
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 1403.
Each school counts as 1 event.??????????????????????????????????
Total number of ARISS ISS to earth school contacts is 1336.
Each contact may have multiple schools sharing the same time slot.
Total number of ARISS supported terrestrial contacts is 48.
?
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:
https://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
https://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. 63 now on orbit
Kate Rubins KG5FYJ
Sergey Ryzhikov
Sergey Kud-Sverchkov
?
SpaceX-Crew 1 now on orbit
Victor Glover KI5BKC
Mike Hopkins KF5LJG
Soichi Noguchi KD5TVP
Shannon Walker KD5DXB
?
****************************************************************************
73,
Charlie?Sufana AJ9N
One of the ARISS operation team mentors
?
?
?
?
?
?
?
?
?
?
?
------------------------------
Message: 7
Date: Fri, 27 Nov 2020 18:26:04 +0000 (UTC)
From: KENT BRITAIN <wa5vjb@?????.???>
To: "amsat-bb@?????.???? <amsat-bb@?????.???>
Subject: [amsat-bb] Fiberglass Cross-boom Alternative
Message-ID: <782090003.2160132.1606501564057@????.?????.???>
Content-Type: text/plain; charset=UTF-8
Hi Tony:
Thanks for giving me a topic for my next CQ Antenna Column.
This topic comes up every few years and also affects the hams who mount?
a vertically polarized Yagi on a vertical mast.
On the antenna range you quickly see that metal (or even plastics) near the
tip
of a Yagi element moves it down in frequency.?? When I have a Yagi on the
range, I put a small bit of Yagi element on a stick and hold it near each
element
while watching gain.????
Get the metal near the tip and gain goes up,?? Element too Short!Get the
metal near the tip and gain goes down.?? Element too Long!
This lets you do a quick look at how well the Yagi is working.
So it is the supporting mast near an element tip that does the detuning.With
a non-conductive mast what do you do with the coax??
Did you run it back down your fiberglass mast???? You just? #@??? your??
non-conductive mast with a conductor.
Yes, I did measure a few tenths of a dB degradation, but the alternative
is a long loop of coax out the back of the antenna.?? How much loss do??
you think is in that loop?
So mounting the Crossed Yagi so that both sets of elements are 45 deg to??
the mast and midway between element sets is the 2nd best solution.?
Best solution would of course be end mounting.?? But that his it's own??
problems if you have a lot of elements!??? Coax can be run back along the?
Yagi boom and along the mast with no measurable effects.?
Also extend the mast just enough for the antenna clamp to get a good grip.?
That is, have the mast extend only an inch or so beyond the clamps.?
Yes, had an interesting talk with Mr. LFA at Dayton several years ago.?
I pointed out that the antenna he had on display could NOT have produced
that polar plot!?? He was simplifying his model to get a cleaner plot.? .?
Kent? WA5VJB/2E0VAA/G8EMY
PS? As an FYI don't think the solution is a Carbon Fiber boom.????? At
Microwave Update I demonstrated a 915 MHz Yagi made using
????? Carbon Fiber Rod for the elements.? Gain about the same as Aluminum.?
????? Another FYI.?? Voyager 1 and 2 use a 10 foot Carbon Fiber parabolic
dish antenna.????? They took the antennas out on the antenna range and they
meet specification.?????? As a weight saving they were NOT metalized.?
??????
Subject: Re: [amsat-bb] Fiberglass Cross-boom Alternative?
To: Tony <73guddx@?????.???>, AMSAT-BB@?????.??? <AMSAT-BB@?????.???>
Don't dismiss using a metal cross-boom. People say it won't work without
actually examining the problem. When antenna guru Kent Britain, WA5VJB
looked at the problem he found a metal boom to work quite well. He then
tested it on the antenna range and verified it worked.? You can see the
paper he presented at an AMSAT symposium here:
Using Metal Cross Booms w/ Satellite Antennas
When I had a permanent satellite station I used a metal cross-boom, and
there were several others in the OSCAR-13 and AO-40 era that did.
73,
Gary "Joe", kk0sd
-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces@?????.???> On Behalf Of Tony via AMSAT-BB
Sent: Tuesday, November 24, 2020 6:00 PM
To: AMSAT-BB <amsat-bb@?????.???>
Subject: [amsat-bb] Fiberglass Cross-boom Alternative?
All:
Is there a cheaper non-metallic alternative to fiberglass cross booms?
Or maybe a wholesale fiberglass rod distributor that has such a beast at a
reasonable price?
Tony -K2MO?
|
|
| |
Using Metal Cross Booms w/ Satellite Antennas
|
|
|
------------------------------
Message: 8
Date: Fri, 27 Nov 2020 23:29:11 +0000 (UTC)
From: "Bob Liddy (K8BL)" <k8bl@?????????.???>
To: 73 Bob W7LRD <w7lrd@???????.???>, AMSAT BB <amsat-bb@?????.???>
Subject: Re: [amsat-bb] vertical antenna
Message-ID: <838255703.2219667.1606519751270@????.?????.???>
Content-Type: text/plain; charset=UTF-8
Bob W7LRD,
Keep in mind that SATs tumble during their flight in space todifferent
attitudes. When the SAT antenna is vertical with respectto your vertical
antenna, the signal level will be at its best. But, whenit is horizontal
with respect to your vertical, it will be at its worst by20 dB or more. That
will be a very deep fade.
So, as the SAT tumbles, you would experience fading from 0 to 20 dBeven if
the SAT was completely facing you in the same plane. As it?turns away from
you, it could even be wore. That's why gain antennasare helpful to make up
for some of those drawbacks.?
In the link below is a chart showing the polarization losses when
theantennas are in the same plane. I found it interesting that the loss
isonly 3 dB when the angle is off by 45. It really gets severe in the next45
degrees (20 dB!!).
GL/73,? ? Bob K8BL
http://www.tscm.com/polariza.pdf
-----------------------------------------------------------------------------
I wrote a blogpost about vertical antennas (in german - maybe google
translate can help you). But there are some radiation patterns in the
article from different antennas. They can help you for understanding in
which situation it works also with satellite.
https://www.michi-dani.ch/2020/10/21/es-geht-auch-mit-rundstrahlenden-antennen
/
73s Michael
hb9wdf
----Urspr?ngliche Nachricht----
Von : amsat-bb@?????.???
Datum : 26/11/2020 - 23:28 (MN)
An : amsat-bb@?????.???
Betreff : [amsat-bb] vertical antenna
anyone using a vertical antenna for the FM satellites?? Which one & how does
it work?
73 Bob W7LRD
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End of AMSAT-BB Digest, Vol 15, Issue 445
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