HamTV Bulletin 3
Gaston Bertels – ON4WF
Ham Video Campaign 2013
The ARISS DATV transmitter, dubbed « Ham Video », already onboard the International Space Station, will soon be installed in the Columbus module and commissioned.
Commissioning will be done in several steps, each during a full pass of the ISS over the Matera ground station (see Bulletin 2). It is not yet known if these passes will be chosen in close succession, or if they will cover several weeks. ARISS proposes ESA to operate so called “blank” transmissions during the commissioning period. If this is accepted, it means that Ham Video will transmit permanently without camera. The camera will not be used because it is fed on batteries and servicing it would need prohibitive crew time. Transmitting recordings is part of a future project, but not available presently.
Although ground stations will receive a black image without audio, “blank” transmissions contain all information needed for the setting up and the fine tuning of the station. Moreover, collected data will be used for a performance study of the ARISS L/S-band antennas as well as for an evaluation of the global system.
For this launch campaign, ARISS addresses a call for collaboration to the amateur radio community, especially to the operators interested in space communications. Several satellite operators have shown interest.
Ham Video technical characteristics are available at www.ariss-eu.org . Look for the “Ham Video” link in the left sidebar. Suggestions and useful addresses for the setting up of a Ham Video ground station are also provided.
Among the components of a satellite ground station, the antenna system is the most expensive. High gain antennas are needed, moved by azimuth and elevation motors and driven by an appropriate computer program. For Ham Video reception, a 1.2m dish with precision tracking is recommended. A station compliant with the recommendations provided in the aforementioned reference text should be capable of 3 to 4 minutes of DATV reception during a pass of the ISS. AO-40 operators who still have an S-band dish can now use it for Ham Video.
On the other hand, interesting data can be gathered by stations with a much simpler setup. A dish with a self made helix feed could be used without motors. This antenna could be positioned in a fixed direction, determined before a pass of the ISS, pointing to the position of the ISS at closest approach, which corresponds to the maximum elevation of the space station during the pass. With the setup as described hereunder, 1 to 2 minutes of solid reception of the Ham Video signal should be possible.
Call for participation to the Ham Video launch campaign
ARISS addresses a call to amateur radio experimenters who would like to participate to the Ham Video launch campaign.
Data gathering during the initial “blank” transmissions is important and the help of volunteering operators will be most appreciated. More details to follow.
It is to be noted that builders of the hereunder proposed “Simple Station” could later update their equipment and add tracking motors. Chained stations will be needed for ARISS Ham TV school contacts. Video and audio from the ISS will be web streamed to the schools over the Internet.
We will keep you informed of these developments. For the time being, as a starter, let us concentrate on receiving “blank” transmissions.
Contact with Istituto Comprensivo Statale “E. Fermi – A. Oggioni”, Villasanta, Italy, was successful. ESA astronaut Luca Parmitano answered 15 questions and listened to the greetings from the school administrator before LOS.
To watch a video of this event click here.
September 10, 2013
HamTV Bulletin 2
Gaston Bertels – ON4WF
Ham Video - EST and Simulations
Ham Video Commissioning preparation is progressing. An EST (Experiment Sequence Test) has been performed 28-29 August and Simulations tests were done 5-6 September 2013.
The EST consisted of a series of tests, mainly of the ground segment. For the Commissioning, the VLBI (Very Long Baseline Interferometry) station of the Italian Space Agency (ASI), located near Matera, southern Italy, will be used for receiving the DATV signals from the ISS. For the EST, the IK1SLD ground station, situated at Casale Monferrato, northern Italy was used. IK1SLD is one of the ARISS telebridge stations, fully equiped for VHF and UHF. It was recently upgraded for S-band with a 1.2m dish, feed, downconverter and precision tracking motors.
For the EST, a very low power transmitter, installed in the shack, generated signals on the Ham Video frequencies, transmitting a DATV recording at 1.3 and 2.0 MS/s and FEC ½. The DATV signal was received and decoded by the IK1SLD station and webstreamed to the BATC server.
B.USOC (Belgian User Support and Operations Center – ESA) conducted operations. B.USOC and EAC (European Astronaut Center – Cologne, Germany) specialists operated from Livorno at Kayser Itallia's laboratory, where a Ham Video unit, the so-called EBB (Elegant BreadBox), is operational. Parties involved were interconnected per teleconference. At Casale Monferrato, Claudio Ariotti IK1SLD and Piero Tognolatti I0KPT produced, received and webstreamed the signals in the different configurations as requested by B.USOC. ESA and ARISS observers participated to the EST teleconference. After debriefing, the EST was declared successful.
Simulations were done differently. B.USOC supervised from their offices in Brussels and ARISS responsibles Piero Tognolatti I0KPT and Jean Pierre Courjaud F6DZP operated from home. The simulations were done in the Columbus mockup at EAC, where a non operational Ham Video model is installed. This box is used for astronaut training on Ham Video. A KuPS power supply was also used, as well as a camera similar to the one onboard Columbus in space. Ham Video transmissions were simulated in the different configurations (frequencies and symbol rates). A view of operations in the Columbus mockup was webstreamed to the participants. ARISS operators simulated reception as if thery were at the Matera ground station, taking into account expected timing between AOS and LOS. They signaled AOS and requested “crew“ at EAC to transmit in different configurations, according a pre-determined scenario. At LOS, the test stopped and results were commented.
Four “passes” were simulated this way, using both ARISS antennas. An important goal of the simulations was to check the efficiency of communications between ground and “crew”. Commands were initiated by ARISS operators (supposedly from Matera), received at B.USOC, relayed to the Columbus Control Center at Oberpfaffenhofen near Munich and uplinked to “crew” by EUROCOM. The European ISS Control Center is called Col-CC and its spacecraft communicator's call sign is EUROCOM. The Simulations were conducted successfully and lessons were learned for gaining time on transmitting commands. This is important considering the limited 8 minutes contact time during real Commissioning.
ARISS proposed to use our VHF uplink capabilities to “crew” for the Commissioning. This was not acceptable with regard to ESA's commissioning protocol.
Presently, ISS pass predictions for Matera are computed for several weeks starting mid October, The Matera VLBI activities are to be taken into account for determining usable passes. Four passes will be needed to fullfil the Commissioning requirements.
Ham Video Commissioning activities will be decided by ESA and NASA ISS Operations. Hopefully the Commissioning will be planned during Expedition 37. We will keep you informed.