“Ham Video” Commissioning Set for Early February
NASA Astronaut Mike Hopkins, KF5LJG, is slated to install the Amateur Radio on the International Space Station “Ham Video” digital Amateur Radio TV (DATV) transmitter in early February. The unit, already aboard the ISS and stowed in the Columbus module, will be commissioned in stages during February and early March. ARISS-Europe Chairman Gaston Bertels, ON4WF, said Hopkins will also install the camera and support arm. The 2.4 GHz transmitter will be connected to the ARISS 41 antenna already installed on Columbus.
“The installation procedure comprises a check of the electrical connections,” Bertels explained. “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.
The European Space Agency conducted commissioning simulations on January 23 and 24, in collaboration with ARISS — an update of simulations carried out last September. The ARISS-EU team will handle signal reception during commissioning.
Commissioning is scheduled in four steps to take place on February 8, 15, and 16, and on March 5. “These dates are still to be confirmed, and this depends on the signature of the Flight Rules relative to Ham Video,” Bertels said. Blank transmissions will start immediately at the conclusion of step 1 and will continue through step 4. “This means that the Ham Video transmitter will operate continuously during 25 days,” Bertels added. The DATV downlink frequency will be 2.395 GHz, DVB-S standard (QPSK modulation). Radiated RF power will be approximately 10 W EIRP. In its ultimate configuration, Ham Video will operate with a Canon XF-305 camera.
Bertels said a “blank” DVB-S signal contains all the data of a normal DVB-S signal, as if the camera were connected. “Receiving a black image and silent sound may seem uninteresting but, from a technical perspective, the digital signal offers an important source of information,” he added. With the proper equipment Earth stations can measure the video and audio stream and decode the DVB tables.
ARISS-EU invites ground stations with S-band capability to provide acquisition of signal (AOS) and loss of signal (LOS) times in UTC, as well as maximum signal level during the pass. These can be determined without the need for any special DATV hardware and software, Bertels said. ARISS is preparing a Ham Video Internet Reporting Program for collecting reception data from volunteering ground stations. He said a “set-top box” or a television receiver with a satellite tuner can be used to receive Ham Video signals during a pass of the ISS.
“When scanning the 2.395 GHz frequency, the DVB stream can be decoded,” Bertels said. “When this is successful, the channel name “HAMTV” will appear on the TV screen.”
More information is available in “Ham TV Bulletin 5” on the ARISS-Europe website.