Category Archives: Satellites

Queqiao S-Band Beacon received over 450000 km

August 23rd, 2018

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.

Reception of ISEE-3

July 30th, 2014

For quite a while now I try to catch a signal of ISEE-3. Because of severe thunderstorms, there was no opportunity to check out yesterday. But today (July 30th, 2014) is the day to listen to this 36 year old bird.

The signal of the beacon on 2,270.414 MHz isn´t too strong, but clearly audible in the speaker. The actual distance is about 1.6 million km, the furthermost man made signal I ever received!

2014-07-30 11_30_21-HDSDRThe downlink transponder A on 2.270.4 MHz uses an antenna array with a gain of 7 dBi, a beamwidth of 12° and circular polarisation. The nominal TX power is 5 W.

The equipment I am using, is just a FUNcube Dongle Pro with a 13 cm ATV converter (LO 916 MHz, IF 1,354 MHz) and a 13 cm LNA near the 23/13 cm dual band ringfeed at my 3 m dish.

Frequency calibration is performed on ordinary 13 cm beacons like DB0UX. The dish calibration is done by optimizing sun noise on 23 cm or the levels of SIRIUS satellites on 13 cm.

The rhythmical fading of the signal seems to be caused by the space probe´s spin of 19.76 revolutions per minute.