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
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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