The following articleis taken from the July 2022 newsletter of the Wagga Amateur Radio Club – thanks to Peter VK8ZZ who is a member of that club.
Yes, it is quite possible but requires a satellite based repeater to do it. The best terrestrial 70cm. contact I have made is only about 250Km. But with the availability of amateur repeaters onboard satellites, far greater distances are possible. I have made a number of overseas contacts using the current active satellite repeaters, generally only as far as Indonesia and New Zealand because of the small foot print (range) provided by the satellite itself. Many of the satellites are “low orbiting satellites” (LOS) and are only up about 400-500 Km. Altitude.
The International; Space Station (ISS) will give good coverage of all of Australia on a midcontinent pass. With a favourable pass, you could just work NZ or Indonesia. The High Orbiting Satellites, like RS 44 (pic. left) and AO 7, are up at altitudes of over 1500 Km. These have linear transponders and allow the use of SSB mode for voice contacts. I have worked both of these satellites and my best achievement was on 19th Sept. 2021, on RS 44, when I worked 3 countries and 4 VK states on a single pass. It started with DU9JJY in the Philippines (5145 Km.); VK8JM in Darwin; VK6AKI in Perth; VK2DRB near Nowra; VK7DW in Launceston and finally ZL3MH in Christchurch (2504 Km.)!
I was alerted by VK6GC, that there was a station, E21EJC, in Bangkok who was regularly in contact with him in Perth, via satellite, that he was seeking more contacts with VK stations and regularly calling CQ on RS 44. Picking the right pass would just allow this satellite’s foot print to reach as far as VK2 and VK3. Looking at future passes of RS 44, told me that this could be done with a particular pass on the 21st May when E21EJC was just about to lose the satellite (2 deg elevation at his location), it would be rising to about 6 deg elevation for me. This would give me about a 2 minute contact opportunity!
The satellite is in an elliptical orbit and its height varies from about 1200 to 1500 km. In order to get maximum range and foot print, I had to pick an orbit where the satellite would be at its maximum height over Australia! The pass would occur at 2.20pm. The satellite would have an altitude of 1510 Km., that would be at a distance of 4030 Km. from me and travelling at 7Km./sec.! Meaning that I will be receiving it on my 70cm downlink at a distance of around 4000 Km. Pretty good for receiving 5W at 435 Mhz! The contact was subsequently made and signal reports exchanged. E21EJC actually posts videos of his contacts to Youtube and I subsequently feature a further 3 times from later contacts with him. Our direct path distance, as estimated from his QRZ.com details, is 7177 Km! So 7000 Kilometres DX is possible on 2m and 70cm!
Details of my station are: Yaesu 991A in split band mode. Satellite position and frequencies from SatPc32. Antenna is a dual band horizontal yagi, single feed, 6 el on 2M and 11 el on 70cm. plus a Yaesu rotator for azimuth control only. Details on RS 44 are as follows Transmitter power: 5 watts. Beacon: 435.605 MHz – transmits CW call sign RS44 Inverting transponder: Earth-to-Space: 145.965 MHz +/- 30 kHz Space-to-Earth: 435.640 MHz +/- 30 kHz The satellite was launched into orbit on December 26, 2019 from the Plesetsk (USSR) Cosmodrome and is in an elliptical orbit with a perigee of 1175 km, an apogee of 1511 km and an inclination of 82.5 degrees. Its orbit period is about 2 hours.