As is known, the dream of many radio amateurs is to broadcast from a rare country, and preferably from a specific location as the very first. Many do not hesitate to spend all their strength and, of course, significant financial resources for this goal. Recently, there was a news in the media that a radio amateur is going to broadcast - from the International Space Station! Of course, this is nothing new, there have been several broadcasts from this space object in the past (see the links below), but so far these have been purely technical or educational activities. This time, however, it is supposed to be a typical expedition, which, in order to achieve its goal in full, assumes the recognition of this station as an independent country DXCC. To znamená, že musí spĺňať pomerne prísne kritériá – podaná žiadosť o zaradenie do zoznamu vychádza z bodu 2B – ostrovné oblasti (tu je diskutabilná orbitálna výška, ktorá pri perigeu nesplňuje požadovaných 350 km) alebo 1C – politický subjekt vychádzajúci z medzinárodného charakteru objektu (nepatrí jednému štátu). Ak ani toto neprejde, loby je pripravené presadzovať zaradenie podľa článku 3 – špeciálne oblasti, vzhľadom na špecifickosť objektu.
Behind the whole event is a group of HAMs from the USA and Finland; for understandable reasons – it is not a small matter, a broad technical but above all financial security of the event is necessary. So-called space tourists occasionally visit the station (currently, a fifth person is about to visit), but the price for an individual's private stay is in the order of tens of millions of US dollars, which is too much for most amateurs (already exhausted by building their own QTH) neskutočný sen. Aj tak je nereálne, aby sa akcie zúčastnilo viac ľudí – operátor bude len jeden. Podľa dohody účastníci akcie každý zložia predpísanú čiastku a až los určí, kto bude šťastlivcom – operátorom expedície.
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Technical aspects
However, the event also brings other difficulties, primarily technical. Up to now, the activities have taken place mainly in bands VHF, however, the interest of opposing stations is mainly in short waves, and as much as possible in the bands. Today, it is not a problem to cover all the required frequencies with one transceiver (the main and back-up transceiver of a suitable small design has already been promised as a sponsor by the Yaesu company), the problem is antennas and final stages. For obvious reasons, it is not possible to place the antennas inside the station (poor efficiency, interference with reception, interference with the devices on board), it is necessary to place them outside. For this, it is necessary to ascend into free space (so-called EVA - Extra-vehicular activity), which is very dangerous and has not been allowed for space tourists until now. NASA refused to participate in the EVA (despite the offered financial amount), so there is no choice but for the amateur to stretch the antennas himself.
Antennas
The upper KV bands are relatively unproblematic, where verticals are expected to be installed (direction indicators have been abandoned; firstly due to weight and then due to the rotation of the station, which would constantly direct them elsewhere). Much more interesting are the lower KV bands, where only wire antennas come into consideration. Due to the dimensions of the station, it will be possible to install a dipole on 7 MHz, but there is nowhere to tie the ends on 160 and 80 m. The solution was found - to leave the ends free! Thanks to the state of weightlessness in space, the wire will not fall, it will stay where it is. Just "shoot" it correctly, it will unfold and stay in position. The rotation of the station will create a weak centrifugal force, which will ensure its permanent tension.
End stage
The appropriate final stage is another intensively debated point. There are two limiting factors - the possible power input, so as not to exceed the capacity of the on-board power grid, and the released heat, which could increase the temperature in the station. That is why the choice was made for a transistor variant with a small power of 500 W. So the signals will not be as strong as we are used to.
Effect of spread
Špecifikou expedície je aj prevádzkový štýl, predovšetkým vplyv šírenia – ionosféry. Doterajšie expedície sa nachádzali na povrchu Zeme, kde dochádzalo k odrazu od ionosféry. Čo sa však stane, keď bude protistanica uprostred vrstvy F? Šťastím súčasného obdobia nízkej slnečnej aktivity je, že na horných pásmach budú optimálne podmienky, keď bude pásmo úplne zatvorené, teda pri nízkej ionizácii, kedy vlny prechádzajú bez výraznej absorpcie a odrazu. Predpokladá sa, že nebude nutné používať split operation - ground stations will not hear anything else anyway and will not be disturbed. However, it is assumed that all earth stations will not call on the same frequency so that the operator can dial undisturbed in the pileup. Lower bands can be problematic due to D and E layer absorption. Optimal times will be selected based on experiments (with expected scientific benefit). The log will be available online on the existing packet radio BBS (145.800 MHz, 1200Bd AFSK); an on-board web server variant is also being considered, but is unlikely to be implemented due to the risk of overloading and crashing. At the end of the expedition, the complete log will be uploaded to the Logbook of the World (helping to recognize the status of a separate "country").
The expedition is also preparing a technical innovation – the entire operation will be continuously recorded and stored together with the frequency as an MP3. After the end of the event, every amateur will receive a pri QSL aj časť záznamu, kde je jeho signál.
Due to the expected enormous interest and previous delays, details are not being released until a launch date is set. Preparations are in full swing, we have a lot to look forward to!
References:
[1] [http://www.nasa.gov/missions/shuttle/f_hamradio.html](http://www.nasa.gov/missions/shuttle/f_hamradio.html)
[2] [http://spaceflight.nasa.gov/station/reference/radio/](http://spaceflight.nasa.gov/station/reference/radio/)
[3] [http://edmall.gsfc.nasa.gov/aacps/news/Ham_Radio.html](http://edmall.gsfc.nasa.gov/aacps/news/Ham_Radio.html)
73 on April 1, Pavel OK1DX