[amsat-bb] Upcoming HamTV ???

Sat May 7 17:23:41 UTC 2016

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 at 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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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 at 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

-- 
Research Associate
Ted & Karyn Hume Center for National Security & Technology
Virginia Polytechnic Institute & State University
Work Phone: 540-231-4174
Cell Phone: 540-808-6305

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