HAM VIDEO announcement

Messagede F6DZP » Mar 11 Juin 2013 13:32

Ham Video

A DATV transmitter on Columbus


1. The Columbus project
As far back as the year 2000, a proposal for an ATV system on the International Space Station was submitted to the ARISS Project Selection and Use Committee by Graham Shirville G3VZV.
November 2002, a request for amateur radio facilities on the then under construction Columbus module was submitted to Mr Jörg Feustel-Büechl, Director of Manned Spaceflight and Microgravity Directorate of the European Space Agency (ESA).
The request was to install wideband amateur radio antennas on the nadir of Columbus, facing the earth. With such antennas, the on board amateur radio facilities could be extended to amateur TV.
In 2003 the request was examined in detail and finally accepted. ARISS would pay for the development, manufacturing and qualification of the antennas. ESA would support the installation cost.
ARISS-Europe started a funding campaign, all donations being published on the website.
In 2004 coaxial feed throughs were installed on the port cone of Columbus. This was needed for accessing the antennas with feedlines from inside the module.
In 2005, the Royal Belgian Amateur Radio Society (UBA) signed a contract with the Wroclaw University of Technology, Poland for the development and manufacturing of the antennas. Whereas initial plans were for UHF, L-band and S-band antennas, only L- and S-band antennas could be ordered by lack of funding. The cost of the project was 47.000 Euro.
Early 2006 the antennas were delivered to ESA. Meanwhile main Columbus contractor EADS and subcontractor Alenia Spazio had reviewed mechanical and thermal constraints. Wroclaw University proceeded to qualifications tests (cost 3.000 Euro) and the antennas failed.
In 2007 an additional contract was signed with the Wroclaw University for the development of modified antennas. This amounted to 36.000 Euro. These antennas were accepted and installed on Columbus, October 2007.
The cost of the antennas finally amounted to 86.000 Euro and was covered by a wordwide funding campaign.
ESA supported the total installation cost of the antennas, including feed throughs and coaxial cables.
After the successful launch of Columbus and its integration into the International Space Station complex, an ARISS-Europe working group started a study for the development of an amateur television transmitter on Columbus, using one of the the S-band antennas. A debate started between the supporters of analog television (ATV) and the proponents of digital television (DATV). The working group, which met monthly per teleconference, made progress, but was stuck by the lack of funding.
Meanwhile a possibility opened for the installation of VHF/UHF antennas on Columbus. The European Space Agency wanted a VHF antenna for a specific payload and was interested in the manner ARISS antennas had been attached to handrails on the Russian service module. A similar system was adopted for Columbus and, in the same time, ESA accepted the installation of a dual band VHF/UHF antenna for ARISS. This antenna project was funded entirely by AMSAT-NA and volunteers who built the antennas for both the ESA experiment and for ARISS. The installation was done per EVA, 21 November 2009. Soon an Ericsson UHF transceiver, which had served in the early ARISS days, migrated from the Russian to the American segment of the Space Station and started Packet Radio operation.
As time went by, the debate on ATV versus DATV evolved at the advantage of the latter, but no funding was in sight… Then, suddenly, supported by the enthusiasm of Italian astronaut Paolo Nespoli IZ0PA, who had performed many ARISS school contacts during his 2010-2011 expedition aboard the Space Station, at the initiative of AMSAT Italia, an Italian manufacturer, Kayser Italia, presented a project for an amateur radio DATV transmitter to ESA’s educational services. In 2012, this proposal was accepted and ESA signed a contract with Kayser Italia for the development and the manufacturing of a DATV transmitter on S-band. This transmitter, dubbed “Ham Video”, is presently slated for launch on HTV-4, August 4, 2013.

2. Ham Video
The Ham Video DATV transmitter, developed for installation in the Columbus module, features the following characteristics:
• Downlink frequencies:
2.422 GHz
2.437 GHz
• DVB-S standard (QPSK modulation)
• Symbol rates: 1.3 Ms/s and 2.0 Ms/s
• FEC : ½
• SIF: 352x240 or D1:720x480
• RF radiated power : approximately 10 W EIRP
Ham Video will operate with a Canon XF-305 camera, provided by NASA.
Power will be provided by a portable power supply, also known as KuPS, another Kayser Italia product. The KuPS is a standard equipment on Columbus, used for several experiments. It converts the 120VDC, which is the standard main voltage in the American segment, to 28VDC.
Ham Video is downlink only. No DATV receiver is presently considered on board Columbus.
From a technical perspective, Ham Video is a standalone payload.
ESA puts Ham Video at the disposal of ARISS for educational outreach.
When video enhanced ARISS school contacts will be performed, the downlink audio and video signals will be produced by Ham Video and the uplink audio signals will be received with the Ericsson transceiver. In this two way setup, the global system is dubbed Ham TV.

3. Ham TV
An important element of the Ham TV system is the ground segment.
Receiving DATV signals from Columbus will be far more demanding than receiving VHF or UHF. A careful study of the link budget, conducted by Piero Tognolatti I0KPT, shows that DATV decoding should be possible, for a ground station equipped with a 1.2m dish, when the ISS is within a range of about 800 - 1000km. This limits the time of DATV reception to about 3 – 4 minutes during a favourable pass.
A 1.2m dish has a beam width of about 4 degrees (between -1 dB points). ISS tracking will be far more demanding than it is for receiving VHF signals.
ARISS will establish a chain of 5 volunteering amateur ground stations, located at carefully chosen places along a typical ISS pass over Europe. These stations will receive and decode the DATV signals and stream the audio and the video over the Internet to the BATC server in UK. The school will connect to the BATC server which offers the possibility to visualise up to 6 images simultaneously. With this setup, Ham Video reception is expected to reach the 15 minutes goal ESA has fixed.
ARISS’ expectation is, that similar chains of ground stations will be established in other continents, allowing more flexibility for Ham Video enhanced ARISS school contacts.
Ham Video transmissions will not be limited to school contacts. Automated transmission of recorded video can also be envisaged. Several amateur radio experiments can be developed, within the limits proper to the International Space Station.
A new era opens for amateur radio on the International Space Station.
Gaston Bertels, ON4WF
ARISS-Europe chairman
F6DZP
 
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