[amsat-bb] Ham Video

[Gaston BERTELS]

HamTV Bulletin #5
January 26, 2014


Ham Video Commissioning – Blank Transmissions

As announced December 22, 2013 the Ham Video 
transmitter is onboard the International Space 
Station and stored in the Columbus module. It is 
slated to be installed February 5, 2014 by 
Michael Hopkins KF5LJG. Hopkins will also install 
the camera and the supporting Bogen arm.
The Ham Video transmitter will be connected to 
the ARISS 41 antenna and to the KuPS power 
supply. The installation procedure comprizes a 
check of the electrical connections. The 
transmitter will be powered on and will transmit 
a signal on 2.422 GHz. This check will be very 
limited in time, just enough to verify that the 
control LEDs are nominal. Then Ham Video will be 
powered off, ready for the first Commissioning Step.
January 23 and 24, Commissioning Simulations were 
again performed by ESA, in collaboration with 
ARISS. The ARISS Team, in charge of receiving the 
signals during the Commissioning, worked with 
B.USOC, simulating the four scheduled 
Commissioning Steps. The procedure was an update 
of the Simulations performed 5-6 September 2013, 
as reported in HamTV Bulletin #2. (All HamTV 
Bulletins are archived at <http://www.ariss-eu.org/>www.ariss-eu.org ).
The four Commissioning steps are scheduled 
February 8, 15 and 16 and March 5. These dates 
are still to be confirmed and this depends on the 
signature of the Flight Rules relative to Ham Video (see HamTV Bulletin #4).
Blank Transmissions will start immediately at the 
conclusion of Commissioning Step 1 and will 
continue till Commissioning Step 4. This means 
that the Ham Video transmitter will operate continuously during 25 days.
The DATV signal parameters will be:
    * Downlink frequency: 2.395 GHz
    * DVB-S standard (QPSK modulation)
    * Symbol rate: 1.3 Ms/s
    * FEC : ½
    * Video PID = 256
    * Audio PID = 257
    * RF radiated power : approximately 10 W EIRP
Ham Video will operate with a Canon XF-305 
camera, but the camera will be turned off during the Blank Transmissions.

Blank Transmissions
A « blank » DVB-S signal contains all the data of 
normal DVB-S. The information tables describing 
the content and the content itself, i.e. the 
video (black) and the audio (silence), are the 
same as for the image and the sound produced by a camera.
Receiving a black image and silent sound may seem 
uninteresting but, from a technical perspective, 
the digital signal offers an important source of information.
The decoded signal provides many data :
    * the video stream can be measured (Tutioune + TS reader)
    * the audio stream can be measured (Tutioune + TS reader)
    * the DVB tables can be decoded (satellite 
receiver (Set Top Box) or Tutioune or TS reader or VLC 
)
The DVB tables mention the PIDs (content 
identification numbers) as well as the SDT 
(Service Description Table) with the TV channel name, which will be « HAMTV »
Even without decoding, several measurements of 
the received signal provide valuable information:
    * analogic HF signal strength  (dBm)
    * analogic Signal/Noise ratio (dB)
    * digital Signal/Noise ratio = MER (dB)
    * error/correction ratio = Vber, Cber 

    * validation of the received transport stream = TS


Reception Reports
Ground stations with S-band capability can 
provide valuable information, which will be much appreciated.
Basic data such as:
    * noise level without signal
    * AOS time (UTC)
    * maximum signal level during pass
·         LOS time (UTC)
can be reported by ground stations without the 
need of special DATV hard- and software.
ARISS is preparing a Ham Video Internet Reporting 
Program for collecting reception data from volunteering ground stations.
These most needed reception reports will be gratefully accepted.

Basic DATV receiver
A “Set Top Box” or a Television receiver with 
satellite tuner can be used for receiving Ham 
Video signals during a pass of the ISS.

When scanning the 2.395 GHz frequency, the DVB 
stream can be decoded. When this is successful, 
the channel name « HAMTV » will appear on the TV screen.




Windows computer with TechnoTrend TT S2-1600 card and Tutioune software

A Windows computer with TT S2-1600 receiver card 
can be used for Ham Video reception. See appended 
Block Diagram of N6IZW Station.

The Tutioune software, developed by Jean Pierre 
Courjaud F6DZP, measures and  records  the Ham 
Video signals second per second:
    * HF signal level
    * digital Signal/Noise level = MER (dB)
    * error/correction = Vber
·         validation of the received transport stream = TS

The recorded file can be examined and forwarded to ARISS.

Better even, the data can be forwarded during an 
ISS pass to the TiouneMonitor on 
the   <http://www.vivadatv.org/>www.vivadatv.org 
website. In other words, the data can be observed worldwide, real time.

Tutioune also shows the constellations during 
signal reception (see HamTV Bulletin #4). The TS 
stream can be recorded, but this is less 
interesting since richer information is already available.

Tutioune also decodes the DVB tables and provides 
the PIDs and the channel name  (« HAMTV ») recovered from the SDT table.

73,

Gaston Bertels, ON4WF
ARISS-Europe chairman

Annex: 
<http://www.ariss-eu.org/N6IZW_Station.pdf>www.ariss-eu.org/N6IZW_Station.pdf