Ilmari-2007

Ilmari-2007 on vuonna 2003 aloitetun laiteprojektin ensimmäinen lennätys.

Lennätystiedote

Otsikko: OH2SIX Ilmari lentää elokuussa
Lähettäjä: oh2aue (Michael Fletcher)
Ryhmät: ra.tekniikka
Päivämäärä: Jul 24 2007 12:07:29
Lähettäjätunnus: oh2aue

Se on moro.

Lauantaina, 11.08.2007, säävarauksin, lähtee Ilmari Padasjoelta. Pienestä sateesta ei vielä estettä tule, mutta esimerkiksi liian kova tuuli voi aiheuttaa ainakin viivettä. Koska lähtöä ei voi tarkalleen varmasti ilmoittaa (tähtäämme kello 10:00:aan, mutta viiveitä voi hyvinkin tulla), niin lentoaikataulusta tiedoitetaan 80 metrillä tarkemmin suoraan pelipaikalta. Viestintävirasto on rajannut lennon korkeintaan 6 tuntiin, joten joutunemme keskeyttämään lennon, jos kaikki menee hyvin ja laki- korkeutta saadaan suunnitellusti.

Tilannetta voi seurata tietysti myös siellä Internetissä #ilmari-2007 IRC-kanavalla.

Luettavaa: http://www.kolumbus.fi/michael.fletcher/mietteita_lineaarisuudesta_ilmari_2007.txt

Taajuussuunnitelma (GIF-kuva): http://www.kolumbus.fi/michael.fletcher/ilmari_bandplan_2007.gif

Taajuussuunnitelma (Word DOC): http://www.kolumbus.fi/michael.fletcher/ilmari_bandplan_2007.doc

Ilmarin käyttöohje (englanniksi): http://www.kolumbus.fi/michael.fletcher/Ilmari_operation_manual_2007.doc

Ilmarin "esite" (englanniksi): http://www.kolumbus.fi/michael.fletcher/Ilmari_brochure_2007.doc

Ilmarin "datalehti" (englanniksi): http://www.kolumbus.fi/michael.fletcher/Ilmari_data_sheet_2007.doc

Terv. Michael, OH2AUE

How to work Ilmari-2003 ?

Ilmari-2003 can be worked with any SSB/CW radio combination you have handy for 144 MHz and 437 MHz. The uplink band, the band you must transmit in, is 144 MHz and the downlink band, the band you receive in, is 437 MHz. One thing you must take into account is that the transponder is inverting. This means that if you tune your transmit frequency upwards, your downlink receive frequency will go downwards. Also, your sideband will be inverted, i.e. your default SSB uplink mode (should be LSB on 144 MHz) will be returned to you by the Ilmari transponder as a 70 cm band USB signal. This is because it is designed as a low orbit satellite (high Doppler shift) transponder allowing some cancellation of Doppler.

When working Ilmari-2003, you should always first locate the transponder downlink before transmitting. If the balloon is above the radio horizon for you observation point, you should have no problem whatsoever copying the downlink CW beacon that is close to the ‘passband’, the approximately 38 kHz band that is fully useable by SSB/CW and compatible modes.

You should then note the peak level of the beacon on your receiver S meter. After this, select a spot free of traffic in the passband (you might be able to hear the passband noise in your receiver too) and tune your transmitter to the corresponding uplink frequency calculated from the frequency plan on the right.

Starting with very low power to start with (absolutely no linear amplifiers allowed here !), you can try transmitting a steady carrier like CW and tuning your receiver around a few kilohertz. You should have absolutely no problem hearing your downlink after you have found the correct frequency. Set your transmit power so that your downlink signal is one (1) S unit, i.e. approx. 6 dB below the observed beacon peak level. This is very important so as to avoid causing distortion to everybody else on the transponder.

Please remember that the transponder is very sensitive indeed and the output power is quite sufficient to be copied whenever the transponder is above your horizon. This transponder has been designed to specifications of a low earth orbit satellite !

And a final note: FM is absolutely forbidden on the Ilmari-2003 2m/70cm transponder.

For non-licenced enthusiasts, Ilmari-2003 offers many interesting signals for licence-free reception, like the transponder traffic itself, the 1.3 GHz amateur FM television transmission (you can use a regular TV satellite receiver and preamp with suitable aerial for reception), 70 cm packet telemetry for observing onboard flight data and GPS location information with the same data available in CW over the 70 cm and 80 m beacons.

07.06.2004 Michael Fletcher, OH2AUE & OH2FM Ilmari-2003 Payload Manager AMSAT-OH Chairman http://www.kolumbus.fi/michael.fletcher/ilmari.htm