Hello Everyone,
I noticed that the Monday, 20160509, 0926 UTC planned ARISS contact with The Kings School in the UK says to watch for the HamTV transmitter. Does anyone know any more details about the HamTV side of this? More specifically, it looks like just before the UK contact (descending pass) there will be a good pass over the Eastern US (ascending pass). What are the chances that the HamTV transmitter will be active during the pass over the US? Do they turn the HamTV transmitter on early? Also, I know they have 4 downlink frequency options and two operating modes. Does anyone know which frequency and which mode will be selected on Monday? In the same vein, does anyone know of a good webpage or other resource for determining the operating schedule of the HamTV transmitter or is the upcoming contacts page on the ARISS site the best place?
We recently got our 3.0m Dish and S-Band receiver systems installed in the VTGS and I was hoping to get up early Monday morning and attempt to record the HamTV transmission as ISS passes over the US on its way to the UK for the planned ARISS contact. Hopefully, if I can get a clean IQ recording of the HamTV transmission, we can use the recording to begin developing our GNU Radio DVB-S demodulators to extract the video stream.
Any and all info would be appreciated.
Thanks!
-Zach, KJ4QLP
Hi Zach
In the same vein, does anyone know of a good webpage or other resource for determining the operating schedule of the HamTV transmitter or is the upcoming contacts page on the ARISS site the best place?
One resource that I monitor is the HamTV group on yahoogroups.com https://ca.groups.yahoo.com/neo/groups/HamTV/info
Most of the recent discussion has been UK-centric since most of the HamTV activations have been for their ARISS contacts.
-- 73 de JoAnne K9JKM k9jkm@amsat.org
Also, it's often on even when there are no contacts. It's just that it's only sending a blank signal. See the reports here:
http://issfanclub.com/video-reports
73,
John KG4AKV
On Sat, May 7, 2016 at 12:39 PM, JoAnne Maenpaa k9jkm@comcast.net wrote:
Hi Zach
In the same vein, does anyone know of a good webpage or other resource for determining the operating schedule of the HamTV transmitter or is the upcoming contacts page on the ARISS site the best place?
One resource that I monitor is the HamTV group on yahoogroups.com https://ca.groups.yahoo.com/neo/groups/HamTV/info
Most of the recent discussion has been UK-centric since most of the HamTV activations have been for their ARISS contacts.
-- 73 de JoAnne K9JKM k9jkm@amsat.org
Sent via AMSAT-BB@amsat.org. 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
Hi Zach KJ4QLP I am probably the less qualified person to answer your questions so I'll be short: 1) HamTv during last month and now is ALWAYS ON at 2395 MHz with blank signal apart during some ARISS contact like next monday when you can see live transmision. 2) more info here HAM Video
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3) I normaly receive HamTv from ISS with 1.2m prime focus dish, your 3m dish will give you a better signal when ISS is low but you need a real precise and fast tracking system 4) I have an ISS HamTv I/Q file and if you need it, just shout
73 Fer IW1DTU
On Saturday, May 7, 2016 4:14 PM, Zach Leffke zleffke@vt.edu wrote:
Hello Everyone,
I noticed that the Monday, 20160509, 0926 UTC planned ARISS contact with The Kings School in the UK says to watch for the HamTV transmitter. Does anyone know any more details about the HamTV side of this? More specifically, it looks like just before the UK contact (descending pass) there will be a good pass over the Eastern US (ascending pass). What are the chances that the HamTV transmitter will be active during the pass over the US? Do they turn the HamTV transmitter on early? Also, I know they have 4 downlink frequency options and two operating modes. Does anyone know which frequency and which mode will be selected on Monday? In the same vein, does anyone know of a good webpage or other resource for determining the operating schedule of the HamTV transmitter or is the upcoming contacts page on the ARISS site the best place?
We recently got our 3.0m Dish and S-Band receiver systems installed in the VTGS and I was hoping to get up early Monday morning and attempt to record the HamTV transmission as ISS passes over the US on its way to the UK for the planned ARISS contact. Hopefully, if I can get a clean IQ recording of the HamTV transmission, we can use the recording to begin developing our GNU Radio DVB-S demodulators to extract the video stream.
Any and all info would be appreciated.
Thanks!
-Zach, KJ4QLP
Hi Zach,
Have a look at the english pages here...http://www.vivadatv.org/index.php there is a specific page on the ARISS HamTV project.
The 3 metre dish sounds grand but you will need to have some special decoding software to replace some missing data in the transport stream. The details are given in the forum mentioned above.
If the camera is not connected - this only usually happens for perhaps 5 minutes before the scheduled contact then a blank DVB-S carrier is transmitted usually 24/7. Success is when you see a black screen with a thin blue vertical line down the left hand side of the image. Plus, if you turn up the audio, you can hear a faint system hiss from the equipment on board.
The usual setup is Symbol rate 2.0 Ms/s FEC : ½ on 2395MHz.
I have decoded the signal using a hand held 60cm dish on a near overhead pass. With the 3.8 metre dish at Goonhilly we have been successful for perhaps 8 mins of a 10 min pass. The various appendages (The Soyuz and other visiting modules) do get in the way of the RF and/or cause reflections so the signals can suffer from odd phase and polarisation changes during a pass.
During the Kings School contact your should look at the http://principia.ariss.org/Dashboard/ page as you can see the two dishes we use for the contact and the signals levels that result.
Sadly this is going to be the last ARISS HmTV contact of thePrincipia Mission
Good luck with the GNU radio implementation....I believe that there are a few others working on this challenge in a similar way!
73
Graham G3VZV
-----Original Message----- From: Fer via AMSAT-BB Sent: Saturday, May 07, 2016 6:02 PM To: Zach Leffke ; amsat-bb@amsat.org Subject: Re: [amsat-bb] Upcoming HamTV ???
Hi Zach KJ4QLP I am probably the less qualified person to answer your questions so I'll be short: 1) HamTv during last month and now is ALWAYS ON at 2395 MHz with blank signal apart during some ARISS contact like next monday when you can see live transmision. 2) more info here HAM Video
| | | | | |
|
| | | | HAM Video By Super User | |
|
|
3) I normaly receive HamTv from ISS with 1.2m prime focus dish, your 3m dish will give you a better signal when ISS is low but you need a real precise and fast tracking system 4) I have an ISS HamTv I/Q file and if you need it, just shout
73 Fer IW1DTU
On Saturday, May 7, 2016 4:14 PM, Zach Leffke zleffke@vt.edu wrote:
Hello Everyone,
I noticed that the Monday, 20160509, 0926 UTC planned ARISS contact with The Kings School in the UK says to watch for the HamTV transmitter. Does anyone know any more details about the HamTV side of this? More specifically, it looks like just before the UK contact (descending pass) there will be a good pass over the Eastern US (ascending pass). What are the chances that the HamTV transmitter will be active during the pass over the US? Do they turn the HamTV transmitter on early? Also, I know they have 4 downlink frequency options and two operating modes. Does anyone know which frequency and which mode will be selected on Monday? In the same vein, does anyone know of a good webpage or other resource for determining the operating schedule of the HamTV transmitter or is the upcoming contacts page on the ARISS site the best place?
We recently got our 3.0m Dish and S-Band receiver systems installed in the VTGS and I was hoping to get up early Monday morning and attempt to record the HamTV transmission as ISS passes over the US on its way to the UK for the planned ARISS contact. Hopefully, if I can get a clean IQ recording of the HamTV transmission, we can use the recording to begin developing our GNU Radio DVB-S demodulators to extract the video stream.
Any and all info would be appreciated.
Thanks!
-Zach, KJ4QLP
What are the chances that the HamTV transmitter will be active during the pass over the US? Do they turn the HamTV transmitter on early?
Yes they do. The camera is often connected and downlinking before and after school contacts. It was on over Australia one time at least.
Does anyone know which frequency and which mode will be selected on Monday?
2395Mhz Symbol Rate 2000. DVB-S QPSK. Note there is only one recommended receiver. Other DVB-S receivers may or may not work. The ideal way to test is to generate the EXACT same signal as the ISS (If you can). There is also sample TS files online to test equipment, to see if it works in the real world. 99% of the time there is no video, but normally QPSK downlinking
In the same vein, does anyone know of a good webpage or other resource for determining the operating schedule of the HamTV transmitter or is the upcoming contacts page on the ARISS site the best place?
There is the email list specific for HAMTV. In general live video is currently only used for European direct or telebridge contacts as Europe is the only place with a HAMTV ground network. There is plans for similar networks in Australia and the USA. It has been picked up in Japan too.
Nearly EVERY pass there is what we call "blank transmission" which is the transmitter outputting QPSK modulated transport stream with the stations name and video. However as the camera is not normally connected, you receive black video, with a blue bar on the left side. We would like a proper test card, but this is not possible at present. However these blank transmissions are very useful for testing tracking, and alignment. The recommended setup can log the signal strength every 1 second, giving a very good idea of the performance of the system.
We recently got our 3.0m Dish and S-Band receiver systems installed in the VTGS and I was hoping to get up early Monday morning and attempt to record the HamTV transmission as ISS passes over the US on its way to the UK for the planned ARISS contact.
You can start now to attempt to receive the QPSK transmission. I assume it is on, at least it was 2 days ago.
Hopefully, if I can get a clean IQ recording of the HamTV transmission, we can use the recording to begin developing our GNU Radio DVB-S demodulators to extract the video stream.
There is a recommended set up, which is designed for decoding and recording etc. If not using a recommended setup then it may be hard to test that it will actually work when live video suddenly appears. For example some receivers cannot do low symbol rates or are bad at doing it. Other receivers need the channel "saved" before they will display it. There is also a problem with the downlink format. While it is "standard" DVB-S format, there is some non standard components in the transports stream. This can cause receivers that work fine with DVB-S to not display the video. The problem is missing tables which the recommended software fixes automatically:
See here: http://www.vivadatv.org/viewtopic.php?f=66&t=281
The best way to confirm your setup will work is to recreate the exact same signal as from space and decode that.
In terms of tracking the ISS. Most European ground stations are using modest 4ft dishes which have a wide beam width and make tracking less critical. Larger dishes make tracking much harder especially at high elevations where the ISS appears to move faster.
I would recommend 1) Use TLE files directly from space track (not from AMSAT) updated daily 2) Calibrate the dish using sun tracking or sun radio noise tracking and confirm it is accurate. 3) If you have problems consider using the recommended hardware (DVB-S receiver) and possibly a smaller dish. We also have special Wifi blocking filters available.
Lastly we are looking for US ground stations to offer to receive HAMTV for USA contacts. If you feel you could do this, then we can provide more help with recommended hardware and support to help decode and stream the live video. Ideally we would like a chain of stations across the US for at least 10 minutes of constant overlapping video.
Dan EI9FHB HAMTV Ground station in Ireland
I also forgot that this page now includes ISS-DATV http://www.amsat.org/status/index.php where we can all log reception reports
73 Graham G3VZV
-----Original Message----- From: Daniel Cussen Sent: Saturday, May 07, 2016 6:47 PM To: amsat-bb@amsat.org Subject: Re: [amsat-bb] Upcoming HamTV ???
What are the chances that the HamTV transmitter will be active during the pass over the US? Do they turn the HamTV transmitter on early?
Yes they do. The camera is often connected and downlinking before and after school contacts. It was on over Australia one time at least.
Does anyone know which frequency and which mode will be selected on Monday?
2395Mhz Symbol Rate 2000. DVB-S QPSK. Note there is only one recommended receiver. Other DVB-S receivers may or may not work. The ideal way to test is to generate the EXACT same signal as the ISS (If you can). There is also sample TS files online to test equipment, to see if it works in the real world. 99% of the time there is no video, but normally QPSK downlinking
In the same vein, does anyone know of a good webpage or other resource for determining the operating schedule of the HamTV transmitter or is the upcoming contacts page on the ARISS site the best place?
There is the email list specific for HAMTV. In general live video is currently only used for European direct or telebridge contacts as Europe is the only place with a HAMTV ground network. There is plans for similar networks in Australia and the USA. It has been picked up in Japan too.
Nearly EVERY pass there is what we call "blank transmission" which is the transmitter outputting QPSK modulated transport stream with the stations name and video. However as the camera is not normally connected, you receive black video, with a blue bar on the left side. We would like a proper test card, but this is not possible at present. However these blank transmissions are very useful for testing tracking, and alignment. The recommended setup can log the signal strength every 1 second, giving a very good idea of the performance of the system.
We recently got our 3.0m Dish and S-Band receiver systems installed in the VTGS and I was hoping to get up early Monday morning and attempt to record the HamTV transmission as ISS passes over the US on its way to the UK for the planned ARISS contact.
You can start now to attempt to receive the QPSK transmission. I assume it is on, at least it was 2 days ago.
Hopefully, if I can get a clean IQ recording of the HamTV transmission, we can use the recording to begin developing our GNU Radio DVB-S demodulators to extract the video stream.
There is a recommended set up, which is designed for decoding and recording etc. If not using a recommended setup then it may be hard to test that it will actually work when live video suddenly appears. For example some receivers cannot do low symbol rates or are bad at doing it. Other receivers need the channel "saved" before they will display it. There is also a problem with the downlink format. While it is "standard" DVB-S format, there is some non standard components in the transports stream. This can cause receivers that work fine with DVB-S to not display the video. The problem is missing tables which the recommended software fixes automatically:
See here: http://www.vivadatv.org/viewtopic.php?f=66&t=281
The best way to confirm your setup will work is to recreate the exact same signal as from space and decode that.
In terms of tracking the ISS. Most European ground stations are using modest 4ft dishes which have a wide beam width and make tracking less critical. Larger dishes make tracking much harder especially at high elevations where the ISS appears to move faster.
I would recommend 1) Use TLE files directly from space track (not from AMSAT) updated daily 2) Calibrate the dish using sun tracking or sun radio noise tracking and confirm it is accurate. 3) If you have problems consider using the recommended hardware (DVB-S receiver) and possibly a smaller dish. We also have special Wifi blocking filters available.
Lastly we are looking for US ground stations to offer to receive HAMTV for USA contacts. If you feel you could do this, then we can provide more help with recommended hardware and support to help decode and stream the live video. Ideally we would like a chain of stations across the US for at least 10 minutes of constant overlapping video.
Dan EI9FHB HAMTV Ground station in Ireland _______________________________________________ Sent via AMSAT-BB@amsat.org. 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
participants (6)
-
Daniel Cussen -
Fer -
Graham Shirville -
JoAnne Maenpaa -
John Brier -
Zach Leffke