AMSAT-BB May 2019

139 participants
185 discussions

Dayton amsat
by Mark Kerhlikar 11 May '19

11 May '19

Can anyone on AMSAT board help me sign up for the Thursday Amsat forum at DARA? My call sign and email will not allow me to login to my account and register, and I’m not getting any response from resetting my password. Thanks Mark WD9HBF

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Satellite Demo at McKinney Amateur Radio Club meeting
by Mac A. Cody 11 May '19

11 May '19

All, I will be giving a presentation on FM satellite operations at the McKinney (Texas) Amateur Radio Club (MARC) monthly meeting this Tuesday evening, starting at 7:00PM (00:00 UTC). According to the predictions, LILACSAT-2 will be the only FM satellite passing by during that hour, so I am going to attempt to have a live demonstration. The local AOS will be 00:11:35 UTC, May 15th (7:11 PM Central Daylight Time, May 14th). According to the AMSAT Live OSCAR Satellite Status Page, LILACSAT-2 appears to have been active on early Wednesday (UTC) last week. That is no guarantee, though that it will happen this week. I will be calling during the pass of LILACSAT-2, so I hope that someone will be there to have a QSO. Thanks in advance! 73, Mac Cody / AE5PH

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suitable omni antenna for FM sats?
by Ron VE8RT 11 May '19

11 May '19

We have a newly licenced amateur in DP79. Because they fell a few points of getting their Basic with Honours they do not have HF privileges, their only way to communicate with the outside world is via satellite. Anticipating this possible outcome, that they may not get access to the HF bands, I sent them a hard copy, (no home internet, and its slow and expensive there if you do have it), of the current copy of "Getting Started with Amateur Satellites". As we're heading into the time of year to do any outside work, the most pressing question is what is the best compromise antenna for a base station. Keeping in mind their location, in order to work anyone they'll have to get into the satellites while the satellite is close to their horizon, otherwise the satellite footprint will not cover areas with any satellite operators. Ron VE8RT in DP22 -- Ron VE8RT <ve8rt(a)yknwt.ca>

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JAMSAT report, language support for GRC, Phase 4 Ground update+strategy+test plan, GNU Radio Conference
by Michelle Thompson 11 May '19

11 May '19

My daughter Geneva and I had a wonderful time at JAMSAT Symposium in March 2019! There was a wide variety of talks about so many different payloads, a very special banquet dinner, adventures in Kyoto and Osaka, visits to ham radio stores, getting to see a new ICOM radio up close, lots of Pokemon, a Fire Festival, and making so many new friends. We were welcomed and will never forget the hospitality. A big part of Symposium was the GNU Radio Workshop by Imamura-san. It was an honor to share how we on Phase 4 Ground use GNU Radio in our presentation on Sunday morning. GNU Radio is a digital signal processing framework for software-defined radio. It’s the software that tells the hardware in your radio what to do. We need to be able to quickly and easily set up a software-defined radio to do whatever modulation and coding we want during development of new payloads and new ground stations. In many cases, GNU Radio is the exact right tool for this job. GNU Radio Companion is a Graphical User Interface that allows us to drag and drop functions onto a canvas. We click block outputs to connect to block inputs. When we do this, it creates a directed graph that implements radio functions. The signals flow from beginning to end. Each block modifies the signal, as if it was part of a circuit. The flow graph looks something like a block diagram combined with a software flowchart. GNU Radio has software variables. It can adapt to signal conditions and user input. The workshop at JAMSAT was held after the last talk on Sunday. It was several hours of hands-on training. Participants brought their own computers, installed GNU Radio, and created useful radio flow graphs that worked with real hardware. Several experiments were done in order. Imamura-san kept everything organized through a set of projected slides that had clear instructions. Optimizations and customizations were made so that participants could see how they can use GNU Radio to achieve their goals. The hardware included RTL-SDRs and Plutos. Imamura-san also demonstrated a live video transmission from the podium. Something that I noticed in the workshop was how much easier it would be if this community could use the software if it was in Japanese. I decided to see what was required. After some homework and reading, I got a very simple example working and understood the basic workflow. I asked JAMSAT if they were interested in a localized version of GNU Radio Companion. JAMSAT responded positively and work began in earnest! It started to become clear that after this initial groundwork, that additional languages would be much easier. I reached out to AMSAT-DL next, and got an enthusiastic response there too. As of today, both German and Japanese are in progress! I received an inquiry about Portuguese following the initial announcement that the main menus had successful translations in testing. It's now on the list after we fully test localization for German and Japanese. While at JAMSAT, I was able to give a status update for Phase 4 Ground. Phase 4 Ground is a broadband digital microwave system for both terrestrial and space use. It complies with both ITAR and EAR open source and public domain carve-outs, so it’s open to participation worldwide. All engineering is published as it’s created. All are welcome to participate. Phase 4 Ground is best suited for GEO and HEO satellite missions. The uplink is frequency division multiple access. We use a 5GHz uplink. The regenerative repeater payload receives the uplink signals, digitizes them, multiplexes them, and processes them into DVB-S2 and DVB-S2X frames. The downlink is 10GHz. DVB-S2 is Digital Video Broadcasting Satellite 2nd edition. The X stands for extensions down in to Very Low SNR modulation and codings. Very Low SNR is of interest to hams, so we include the extension to the main standard DVB-S2. We use both pilots and short frame lengths in order to make the receiver implementation as easy as possible. Pilot tones are optional, and there are medium and long frames available in the standard. There is a recommended order to receive DVB-S2/X frames. The first stage of the demodulator is symbol timing recovery. We have to figure out the best possible time to measure, or take a snapshot, of the received signal. The receiver does not know the phase of the transmitter clock. We will not be automatically coordinated with it. It's not just a problem with phase, either. The receiver and transmitter may disagree in terms of the period of the clocks, or we might have jitter, or we might have drift. We have to analyze the received waveform and synchronize our receiver clock to the transmitter clock that is “hidden” in the received signal. Then, once we are synchronized, we sample that symbol and report the results. Doing this gives us a reliable value for the received symbol. Now that we have a series of received symbols, we have to figure out the start of the frame. This is done in DVB-S2 (and many other protocols) by sending a fixed pattern at the start of every frame. For DVB-S2, this is called a Physical Layer Start of Frame sequence. It’s 26 symbols long. This is what we look for. Once we see it, we know where the start of the frame is! Frame synchronization can be done in several ways. There are two different methods described in the implementation guidelines for DVB-S2/X. One is relatively simple, using shift registers. The other is bit more complex, using state machines. There are advantages to using the state machine method, but it’s more complicated and expensive. The shift registers is simple and cheap, but gives up a bit of performance. This is the constant balance in digital communications. Performance comes at a cost! Right after frame synchronization, we correct for carrier frequency error. First we do a coarse correction. This can be done with a delay-and-multiply frequency error detector. Then we do a fine correction. This can be done with something like a feed-forward estimation algorithm. Coarse correction is in the MHz, and fine correction is the hundreds of kHz. Next, we do phase recovery. This is to fix any residual frequency offset from the coarse and fine frequency offsets. Phase 4 Ground will support all the modulation and codings of DVB-S2/X, but we expect lower order modulations to be more heavily used. This means that a pilot-assisted maximum-likelihood (ML) feed-forward estimator will be the most useful. If you compute the average phase of each pilot field, then you can subtract this out and improve the signal. Higher-order modulations will need another feedback loop. Automatic gain control is next. AGC can be done in many ways. One way to do it depends on the pilot symbols in DVB-S2/X standard. These symbols are sent at regular intervals to provide a known easy-to-receive signal. We use these known pilot symbols in order to determine the amplitude multiplication factor for the rest of the signal. Pilot symbols are optional in the DVB standard, but Phase 4 Ground requires them. When the pilot symbols are on, the AGC is listening. When the pilot symbols are off, the AGC turns off, and the information from the AGC is used. After AGC, the constellation is decoded. DVB-S2 has a lot of them! There are many techniques to get the bits from the constellations. GNU Radio has a very versatile and powerful constellation block. Instead of the usual MPEG transport stream (DVB-S2 is for satellite TV, so the content is usually broadcast television signals), we use the more flexible Generic Stream Encapsulation standard from DVB.org. This means we have less overhead and complexity, and can handle any digital traffic that the amateur operator wants to transmit. It’s just a digital pipe. Phase 4 Ground uses GNU Radio extensively in research and development as well as for archiving and publishing our work. GNU Radio is not just a tool to figure things out, but is also a way to define a reference design for the radio. Because Phase 4 Ground is not a bent pipe, the payload is more complex. This complexity needs to be fully tested on the ground before risking large digital circuits in space. All the uplink channels are received with a polyphase filter bank. The current polyphase filter bank implementation in GNU Radio needs some updates in order to achieve the speeds and performance that we want. This is an active area of research and development. There have been three efforts over the past three years by various groups that have attempted to update and improve the existing working polyphase filter bank in GNU Radio. There is some recent good news here! EJ Kreinar reported that his open project (Theseus Cores) has an open source FPGA polyphase channelizer! This works with RFNoC. We will experiment with this in our payload design. This could fill in a big piece of the system that we need. Check it out here: http://gitlab.com/theseus-cores/theseus-cores Ron Economos and Paul Williamson successfully implemented GSE in GNU Radio and in Wireshark. This made it possible to do transport layer testing. Ron Economos is the lead author of the DVB blocks in GNU Radio. Improvements to GSE continue today. The current focus is improving internetworking functions so that large amounts of data can be more easily handled. We intend to use multicast IP as much as possible, and making sure GSE integrates well with multicast IP is important. The path forward with that is in our test plan. You can find our test plan here: https://github.com/phase4ground/documents/blob/master/Papers_Articles_Prese… The error correction in DVB-S2/X is state of the art. There are not many other error correcting codes that are better than Low Density Parity Check + BCH. This is a concatenated digital code specified by the DVB standard for S2 and T2 transmissions. We have two open source implementations of LDPC decode for DVB-S2/X. The first one is for graphical processing units and was written by Charles Brain. It was demonstrated at 2017 AMSAT-NA Symposium and at several events following. The second open source implementation is in C by Ahmet Inan and can be found here: https://github.com/xdsopl/LDPC This version has been incorporated into GNU Radio by Ron Economos. This can be found here: https://github.com/drmpeg/gr-dvbs2rx The next step for LDPC is to implement and publish an open source version for FPGA. GNU Radio is very important for our voice codec work, uplink modulation experiments, and trying out authentication and authorization schemes. GNU Radio allows us to use a wide variety of off the shelf hardware to achieve things that were not possible only a few short years ago. The GNU Radio community has been welcoming, helpful, supportive, friendly, and a source of continually amazing software-defined radio advancements. GNU Radio has an annual conference. In 2018, we held a week-long “Block Party” for DVB-S2/X. We had fun, set up multiple demos, explained DVB-S2/X, made the case for open source LDPC, and made progress on DVB-S2 correlates and GSE. Phase 4 Ground made significant progress due to the generous support of the conference organizers and the community. Learn more about the conference here: https://www.gnuradio.org/grcon/grcon19/ Registration for 2019 is open. The conference will be held September 16-20, 2019 in Huntsville, AL, USA. There is a poster session, proceedings, talks, workshops, contests, and social activities. The theme for 2019 is Space Communications! There are special gifts for space themed content. If you have a GNU Radio project that you want to share, consider making a presentation at or sending a poster to GNU Radio Conference 2019. The collaboration between Phase 4 Ground and JAMSAT has been absolutely stellar and we all look forward to continued enjoyment and success. Next generation payloads will be more complicated with multiplexing and advanced digital techniques. We all need to be able to work together, internationally. Open source and public domain is the best way forward. Phase 4 Ground and Open Research Institute are entirely dedicated to making this happen. We will be keeping the momentum and progress going. ORI is proud to be an affiliate member of Open Source Initiative https://opensource.org/ Join the Phase 4 Ground team! Our work benefits all AMSAT organizations. Our mailing list can be found at our website https://openresearch.institute/ Write me at w5nyv(a)arrl.net if you want to join our Slack account. This is where daily engineering discussions take place. More soon! -W5NYV

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non-doppler correction on linear sats
by Hans BX2ABT 11 May '19

11 May '19

How to deal with signals (CW/SSB) where the other party doesn't seem to do doppler correction? I use an Airspy/IC820H combo to receive (2m) and transmit (70cm) and both are controlled by Gpredict so that uplink and downlink on linear sats stay in tune. However, I hear many stations that apparently don't do this and their signals "walk" up very fast, right out of my passband. Difficult to get their call, let alone have a QSO. So what should be my strategy to deal with this? 73 de Hans BX2ABT

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What influences LEO propagation?
by Hans BX2ABT 11 May '19

11 May '19

The last couple of days the Fox birds haven't been coming in as well as before. Signal strengths are down, fading has increased and it is almost impossible for me to open them. Now the sporadic E season also has kicked off in the last few days, with increased activity here in east Asia. Is this a coincidence or do the two have a connection? And are there other factors that influence LEO propagation? I know satellite tumbling is one factor that causes fades, but are there also ionospheric or atmospheric influences? Thanks for the insight. 73 de Hans (BX2ABT)

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DN01/02 GRIDLINE - 2019-05-13 - KI7UNJ
by KI7UNJ Tucker 10 May '19

10 May '19

Will be on the DN01/DN02 Gridline on Monday, May 13th FM Passes Only. AO-92 - 2019-05-13 17:20:05Z (+10 min 59 seconds) AO-91 - 2019-05-13 17:40:28Z (+9 min 44 seconds) AO-92 - 2019-05-13 18:53:19Z (+11 min 2 seconds) AO-91 - 2019-05-13 19:12:58Z (+14 min 10 seconds) Track me on APRS https://t.co/JZc3nbDywp Use DN02HA for Satmatch.com FP predictions -- Casey Tucker KI7UNJ https://twitter.com/KI7UNJ https://www.qrz.com/db/KI7UNJ http://bit.do/ki7unj <https://www.google.com/url?q=http://bit.do/ki7unj&sa=D&source=hangouts&ust=…>

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AMSAT Academy Registration Deadline TODAY at 23:59 UTC / 7:59pm EDT
by Paul Stoetzer 10 May '19

10 May '19

Don't miss out on the AMSAT Academy to be held on Thursday, May 16th, 9am-5pm at the DARA Clubhouse. Registration deadline is TODAY at 23:59 UTC / 7:59pm EDT. https://www.amsat.org/other-events/amsat-activities-at-hamvention-2019/ And don't forget - the deadline for the TAPR/AMSAT Banquet is Tuesday, May 14th at 22:00 UTC / 6:00pm EDT. 73, Paul, N8HM

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Upcoming ARISS Contact Schedule as of 2019-05-09 02:00 UTC
by aj9n＠aol.com 08 May '19

08 May '19

Upcoming ARISS Contact Schedule as of 2019-05-09 02:00 UTC Quick list of scheduled contacts and events: Aranzadi Ikastola, Bergara, Spain, telebridge via VK6MJ The ISS callsign is presently scheduled to be NA1SS The scheduled astronaut is Nick Hague KG5TMV Contact is go for: Fri 2019-05-17 08:51:35 UTC 84 deg 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. International Space Station Astronauts are Calling CQ Students ARISS-US program’s education proposal window is open April 1 - May 15, 2019 March 24, 2019: The Amateur Radio on the International Space Station (ARISS) program is seeking proposals beginning April 1, 2019, from US schools, museums, science centers and community youth organizations (working individually or together) to host radio contacts with an orbiting crew member aboard the International Space Station (ISS) between January 1, 2020 and June 30, 2020. Each year, ARISS provides tens of thousands of students with learning opportunities about space technologies, communications, and much more through the exploration of Amateur Radio and space. The ARISS program connects students to astronauts on the ISS through a partnership between NASA, the Radio Amateur Satellite Corporation, the American Radio Relay League, other Amateur Radio global organizations and the worldwide space agencies. The program’s goal is to inspire students to pursue interests and careers in science, technology, engineering, and mathematics (STEM) and in Amateur Radio. Educators report regularly that student participation in the ARISS program stimulates interest in STEM subjects and STEM careers. One educator wrote, “Many of the middle school students who took part in and attended the ARISS contact have selected science courses in high school as a result of that contact.” Educators are setting up ham radio clubs in schools and learning centers because of students’ interest. ARISS is looking for organizations that will draw large numbers of participants and integrate the contact into a well-developed, exciting education plan. Students can learn about satellite communications, wireless technology, science research conducted on the ISS, radio science, and other STEM subjects. Students learn to use Amateur Radio to talk directly to an astronaut and ask their STEM-related questions. ARISS will help educational organizations locate Amateur Radio groups who can assist with equipment for a once-in-a-lifetime opportunity for students. The proposal window opens April 1, 2019 and the proposal deadline is May 15, 2019. For proposal guidelines and forms and more details, go to: http://ariss-proposal-webinar-spring-2019.eventbrite.com Proposal webinars for guidance and getting questions answered will be offered April 11, 2019 at 7 pm Eastern Time and April 16, 2019 at 9 pm Eastern Time. Advance registration is necessary. To sign up, go to https://ariss-proposal-webinar-spring-2019.eventbrite.com **************************************************************************************************************************************************************************** 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(a)ariss-eu.org 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(a)gmail.com ARISS-Japan, Asia, Pacific and Australia: Satoshi Yasuda, 7M3TJZ email to: ariss(a)iaru-r3.org, 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(a)amsat.org or aj9n(a)aol.com. Listen for the ISS on the downlink of 145.8Ø MHz. ******************************************************************************* All ARISS contacts are made via the Kenwood radio unless otherwise noted. ******************************************************************************* Several of you have sent me emails asking about the RAC ARISS website and not being able to get in. That has now been changed to http://www.ariss.org/ Note that there are links to other ARISS websites from this site. **************************************************************************** Looking for something new to do? How about receiving DATV from the ISS? If interested, then please go to the ARISS-EU website for complete details. Look for the buttons indicating Ham Video. http://www.ariss-eu.org/ If you need some assistance, ARISS mentor Kerry N6IZW, might be able to provide some insight. Contact Kerry at kbanke(a)sbcglobal.net **************************************************************************** ARISS congratulations the following mentors who have now mentored over 100 schools: Satoshi 7M3TJZ with 135 Francesco IKØWGF with 132 Gaston ON4WF with 123 Sergey RV3DR with 114 **************************************************************************** The webpages listed below were all reviewed for accuracy. Out of date webpages were removed, and new ones have been added. If there are additional ARISS websites I need to know about, please let me know. Note, all times are approximate. It is recommended that you do your own orbital prediction or start listening about 10 minutes before the listed time. All dates and times listed follow International Standard ISO 8601 date and time format YYYY-MM-DD HH:MM:SS The complete schedule page has been updated as of 2019-05-09 02:00 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 Total number of ARISS ISS to earth school events is 1305. Each school counts as 1 event. Total number of ARISS ISS to earth school contacts is 1248. 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: DPØISS, IRØISS, NA1SS, OR4ISS, RSØISS **************************************************************************** The successful school list has been updated as of 2019-04-30 02:30 UTC. http://www.amsat.org/amsat/ariss/news/Successful_ARISS_schools.rtf Frequency chart for packet, voice, and crossband repeater modes showing Doppler correction as of 2005-07-29 04:00 UTC http://www.amsat.org/amsat/ariss/news/ISS_frequencies_and_Doppler_correction .rtf 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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Upcoming Satellite Operations Page
by Robert Bankston 07 May '19

07 May '19

It seems that taking your AMSAT gear with you, where ever you go, is now the new norm. From the Queen Mary to Iceland, and all parts in between, satellite operators are making AMSAT's 50th Anniversary a year to remember. Stay informed by regularly checking AMSAT's Upcoming Satellite Operations page, located at https://amsat.org/satellite-info/upcoming-satellite-operations/ 73, Robert Bankston, KE4AL AMSAT-NA VP of User Services Twitter: @KE4ALabama Website: KE4AL.wordpress.com

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AMSAT-BB May 2019