50 MHz Aircraft Scatter using JT6M mode and AirScout software

On Saturday 10th and Sunday 11th August 2013 I was using the WSJT software data mode JT6M on 50.230 MHz trying to work stations via Meteor Scatter during the Perseids meteor shower.

One particular station I wanted was a DXpedition to IO55VD square in the Republic of Ireland callsign EI9E/P, but at only 350 km from my QTH it was almost too close for this mode.

Despite my best efforts using my Kenwood TS-2000 transceiver, 50 Watts, my PAR OA-50 loop antenna and this station transmitting almost non stop on 50.217 MHz, I only heard EI9E/P calling CQ via very brief reflections or ‘pings’ from meteors and was beginning to give up hope of working him.

EI9E 10.08.2013

However on Monday morning 12th August I tried again at the peak of the Perseids Meteor Shower, but once more the reflections from meteors were extremely brief and he didn’t hear me at all.

What I didn’t realise was that something very interesting was going to be observed by me thanks to EI9E/P transmitting every 30 seconds. As the early Monday morning progressed I noticed that I could now hear and see other 15-60 second long signal reflections from EI9E/P that were a steady strength and definitely not via Meteor Scatter. Below is the best reflection I observed via Meteors at only around 3 seconds long.

EI9E CQ 11.08.2013

Because these other unusual reflections were so different and apparently random, I didn’t immediately know the mechanism behind them, then I wondered could they be Aircraft Scatter reflections?

EI9E ACS BEST 12.08.2013

I fired up the new AirScout software written by Frank DL2ALF which allows real-time prediction for this mode designed for 144 MHz and higher frequencies.

I put in the station details for EI9E/P and myself and looked for the next aircraft likely to cross our path. No signals detected until an aircraft passed, I kept watching and my theory was confirmed, every single long reflection was by Aircraft Scatter with a few extra really different in character and brief reflections via meteors.

Now to put this to use, I waited for some ideal aircraft and called EI9E/P, this time he heard me straight away and with so many aircraft flying now between the UK and the USA I had worked him within 5 minutes!

EI9E G0ISW ACS 12.08.2013 0744

I observed more and noticed I could detect other stations that were too far away for line of sight, too close for Meteor Scatter but I was receiving their JT6M signals via probably Aircraft Scatter again as the reflections were again all between 15-60 seconds long.

One of the stations I observed was David GI4SNA in IO64XM square in Northern Ireland, even closer to me at only 250 km.

Today Saturday 17th August I arranged a sked online with David via the ON4KST chat pages and we started whilst an aircraft was crossing our path. As hoped we completed our JT6M QSO on 50.220 MHz amazingly within only 3 minutes, the aircraft had allowed us continuous Aircraft Scatter (ACS). See screenshot captured below, it was an American Airlines Boeing 777-200 flight number AAL-79!

GI4SNA 17.08.2013 combined

GI4SNA 17.08.2013

N773AN-American-Airlines-Boeing-777-200 GI4SNA 17.08.2013

I am going to experiment  a lot more with 50 MHz Aircraft Scatter now using JT6M and AirScout software they seem to work really well together and I hope to work a lot more stations in locator squares I need that are too close for MS or Sporadic-E, for example IO71, IO72, IO73 and most of Ireland and Scotland.

Please note that the JT6M mode is only now found on older versions of WSJT software version 7.07 being the best source.

Happy days!

73 de Philip G0ISW


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