28 Jul 2019

Oscar 100 - geosynchronous amateur satellite

As many will recall, I take the occasional peek at the Goonhilly web SDR, which monitors the narrowband transponder on Es'hail satellite, also known as Oscar 100.

In my view activity seems lower than a month ago. Certainly activity is not great and has definitely not increased as I once expected. Looking just now on a Saturday afternoon, the most I saw were 5 stations active on SSB at one time. By now I was quite expecting the main issue to be too many stations, possibly overloading the transponder.

It seems people have fun getting a signal through the satellite, then lose interest.

See https://eshail.batc.org.uk/nb/

2 comments:

G1KQH said...

Although reception of the Downlink is made easy with a converted LNB and a small dish taking the LNB IF into a Dongle and using a PC to receive. Transmission of the uplink is too much of a technical challenge for many, hence the black box manufacturers need to get their fingers out and roll out some kit.

73 Steve

Barry G8AGN said...

If you have a rig such as the FT817, which can work on 70cm, then the simplest way to transmit up to QO100 is using a SG Labs 13cm transverter costing just over £200. This can produce just over 2 watts of RF at 2.4GHz which is adequate for cw, ssb and digital modes such as FT8, SSTV, WSPR, RTTY when using an 80cm dish. The transverter can also be used for the terrestrial AR band allocations (just by changing an internal link).

This is all "plug and play" so no technical challenge. The only construction work needed is a feed for the dish and most people seem to be using the one made popular by Mike Willis G0MJW. Full details of its construction etc are at several places on-line.
http://www.hybridpretender.nl/patch.pdf

The feed is also referred to as the POTY feed (patch of the year). Kits of parts are available and just need to be soldered together.
http://www.hybridpretender.nl/

Re activity on QO100, it all depends on when you listen. Breakfast time is often good for DX from the East. Unlike HF, active stations are determined more by the local time rather than propagation conditions (always excellent, except maybe at times of heavy rain).

The wideband transponder is well used by the DATV enthusiasts at all hours of the day. The BATC websdr for wideband cannot be used directly to view TV signals but the associated chat (see text at RHS of the spectrum display) will give you an idea of the level of activity - very busy especially in the evenings).

I accept that sending and receiving DATV signals via QO100 is a big technical challenge for most people but operation via the narrowband transponder really isn't.

73

Barry, G8AGN