Designed as a relay for the planned chinese Chang’e 4 misson to explore the far side of the Moon with a lander and a rover, the Queqiao probe has reached it´s final destination 60000 km behind the Moon. There it is in a halo orbit around the Langrangian L2 point of the Earth-Moon-system. So it won´t be covered by the Moon, seen from Earth.
The signal of the S-band beacon is audible at about 2275.225 MHz. The used equipment is HDSDR software with an RTL-SDR-Stick with a 13 cm ATV Converter (LO=916 MHz), 13 cm LNA (Kuhne) at a 23/13cm and a dualband ringfeed in a 3 m dish.
Queqiao also carries a radio astronomy experiment for low frequency exploration in collaboration with dutch ASTRON. During the fly-by at the Moon two microsatellites Longjiang-1 (DSLWP-A) and Longjiang-2 (DSLWP-B) were released, to enter orbits around the moon. These satellites carry a radio astronomy experiment as well as amateur radio payloads. While Longjiang-1 went lost, Longjiang-2 is operating and can be monitored in the 70 cm band.
This morning I had a look for DB0MFI, a new beacon on 1296.940 MHz in JN58HW. It is audible with 529 constantly via tropo and peaking 579 via aircraft scatter. The power is 5 W into a 4 times stacked big wheel antenna.
In the afternoon I went for it on 2320.940 MHz. Faint reflections on some airplanes were audible and traces could be seen in the waterfall of WSJT-X Wide Graph:
The french beacon F5ZBM is on air again. I found it accidentally, when looking for other french beacons. It is at a new location in JN18MN near Paris transmitting on 1,296.8475 MHz. Nice to monitor it in Mainz via aircraft scatter over a distance of 406 km!
The keying is in F1 with a very narrow spacing. Power is 10 W ERP into a slot antenna, as can be seeen at BEACONSPOT.eu
Tonight I monitored OZ7IGY on 2,320.930 MHz via aircraft scatter. It was nice to see other beacons appearing shortly in the waterfall diagram.
OZ7IGY and friends in time lapse
From left to right:
2.320.900: DB0UX, JN48FX, 105 km, tropo
2,320.910: DB0XY, JN51EU, 263 km, aircraft scatter
2.320.920: DB0VC, JN54IF, 509 km, aircraft scatter
2,320.930: OZ7IGY, JN55WM, 670 km, aircraft scatter
The dish was bearing 20° to OZ7IGY. The -3 dB beamwidth is just 3.2° on 13 cm.
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:
During the morning I was able to monitor GB3FM in IO91OF on 1297.050 MHz and G8MBU in IO90IR on 1296.800 MHz. Now in the afternoon F5ZCS in IN87PT on 1296.959 MHz came out of the noise with a strong signal of 549 with fast QSB. It is my 53rd beacon on 23 cm. The weather here in Mainz doesn´t look like tropo: 8/8 cloudy and wind at 40 km/h.
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.