After installation of new transverters for 23 and 13 cm with stabilized LOs a couple of months ago. I gathered some experience in using JT65C mode on EME. So I undertook a new attempt to receive and decode G8MBU via aircraft scatter today. As antenna I use a 3 m dish with a dual band ringfeed.
Path DJ5AR to G8MBU
The beacon is located at Cowes on the Isle of Wight, IO91IR37, 683 km from Mainz, JN49CV. It runs 2 W power into an omnidirectional dual alford slot antenna. The mode used is JT65c. Nominal frequency is 1296.800 MHz. To successfully decode the signal, the SSB dial should be set to 1296.7986 MHz, to get a tuning tone of 1400 Hz in WSJT.
There is a small window between the Isle of Wight and Mainz, where high flying aircraft can be “seen” from either places. But only a few airplanes cross the path within and fewer fly along the path. Reflections of G8MBU could be seen from time to time, but mostly too weak and too short to provide decodes. It took nearly 3 hours until the first decode happened at -22 dB and just some minutes later a second one appeared on the display at -21 dB:
After the unexpected good result in March on 13 cm, I had a special focus on this band in May contest. Last year I marked my new record in the number of stations worked on 23 cm, this year I improved the new record from March in worked stations on 13 cm. Particularly in the last hour I had the ambition to log at least 40 Stations. So I had QSO #40 in the last 5 minutes with Detlef, DJ3AK, in JO52GJ, 322 km, using aircraft reflections on planes just 50 km from my location, elevating the dish up to 10°: Power Aircraft Scatter 😉
QSOs on 13 cm
With QSOs to Poland, Hungary and Belgium three new countries could be added to the 13 cm list. HG7F (817 km) is my new aircraft scatter ODX. Also some new grid squares could be logged.
And again: After the contest is before the contest! A lot of ideas are in my mind, what has to be improved for the next competitions!
When looking for the annual results of the Italian Activity Contest 2016 on 1296 MHz yesterday, I was really surprised, to be the winner. I haven´t expexted this, as Giorgio, IK3GHY, had a higher score in total all the time. But as he won in 2015, he was out of competition in 2016. I have to respect his success and congratulations for your extraordinary score, Giorgio!
But anyway, it was great fun to work the italian lads every 3rd Tuesday in month. Hopefully, there will be enough time to be QRV in the 2017 events. I am also looking forward to go to Italy in October, meeting friends in Venice and at the Alpe Adria meeting near Udine.
Steve, IU1EAF, will be the contest manager in 2017 and the rules have changed too (english version online now). Thank you to Alfredo, IK2FTB, for all the work in the past year.
Today I configured the MKU 23 G4, I ordered from Michael in Friedrichshafen to perform a RX test. Via aircraft scatter it was no problem to receive the beacons OZ7IGY in JO55WM over 670 km and OK0EK in JN89VJ over 689 km. The sun noise is at a level of 6 dB.
Beacons regulary receivable on 13 cm (green: TR / blue: AS)
The motivation is high now to configure the TX line as well 😉
And another Contest is over. Again I learned a lot and I am happy with the results: With a count of 82 QSOs I broke my personal record in claimed QSOs in a 23 cm contest. Since October1990 the number has been as high as 78 QSOs.
The claimed score is a little more than 30.000 points and a new personal record as well. The 82 Stations, worked on 1296 MHz, are from 12 DXCC countries and located in 41 different grid squares. Countries worked were 40 x DL, 1 x F, 3 x G, 2 x HB9, 1 x HA, 5 x I, 6 x OE, 14 x OK, 1 x OM, 1 x ON, 5 x PA and 3 x S5. In most of the QSOs aircraft scatter was an important factor. 35 contacts were done in CW. ODX, as usual, was HG7F over 817 km, still my ODX via AS. Nice was to work 3 OE5-stations around local midnight within 10 minutes: OE5VRL/5, OE5JFL and OE5RBO.
From Monday, June 22nd to Wednesday, June 24th I will be QRV during the evenings on 23 cm and 13 cm using the special event callsign DL65DARC.
Skeds (aircraft scatter, tropo) are welcome via ON4KST, Facebook or email.
Rig will be a 3 m dish with 150 W on 23 cm and 75 W on 13 cm. The QTH locator is JN49CV. SSB, CW and WSJT modes are suitable. Operation on relays is not intended.
If I find some spare time, I will be QRV on June 25th, 26th and 28th as well.
On Saturday, June 27th, you can meet me in Friedrichshafen.
A long time monitoring of the beacon F1ZMT in JN07CX via Aircraft Scatter on 1296.872 MHz shows asymmetrical reflections on most of the crossing planes.
As the distance to the beacon is 624 km and it´s ERP of just 10 W (a panel antenna to the south combined with an omnidirectional big wheel) is rather QRP, only weak reflections can be detected from time to time. This ensures, that received signals were reflected on single airplanes. In this example can be seen, that the reception starts shortly before the plane crosses the path between DJ5AR in Mainz and F1ZMT in LeMans. Unexpectetly the signal can be seen for quite a while after crossing. There is a continuous variation of the doppler shift and no spread of the signal, as is usual for a moving solid reflector.
The monitoring of distant beacons can be a boring job, even when using the waterfall diagram of a SDR. I prefer SpecJT of the WSJT package in JT65c mode. It is much more sensitive and even at slow speed faint refections can be seen clearly.
The example shows F1ZMT in JN07CX, 624 km from Mainz. The beacon operates 10 W into an omnidirectional antenna on 1296.872 MHz. The reflections in the screenshot were caused by 3 airplanes crossing the path one after the other.
Most spectacular is the ability to track airplanes with the antenna in azimuth and elevation. When enabling tracking, the user can select between several interfaces. I am using the plain WSJT-compatible “azel.dat” file. First tests on DB0NCO are very promising.