Studying Es’hail 2 Doppler

Es’hail 2, the first geostationary satellite carrying an Amateur radio payload, was launched on November 15. I wrote a post studying the launch and geostationary transfer orbit, and I expected to track Es’hail 2’s manoeuvres by following the NORAD TLEs. However, for reasons not completely known, no NORAD TLEs were published during the first two weeks after launch.

On November 23, people found Es’hail 2 around the 24ºE geostationary orbital slot by receiving its Ku-band beacons at 10706MHz and 11205MHz. On November 27, NORAD TLEs started being published, confirming the position of Es’hail 2 around 24ºE. Since then, it has remained in this slot. Apparently, this is the slot that will be used for in-orbit test before moving the satellite to its operational slot on 25.5ºE or 26ºE.

Since November 27, I have been monitoring the frequency of the 10706MHz beacon to measure the Doppler. A geostationary satellite is never in a fixed location as seen from the Earth. It moves slightly due to imperfections in its orbit and orbital perturbations. This movement is detectable as a small amount of Doppler. Here I study the measurements I’ve been doing.

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Es’hail 2 launch in GMAT

After a long wait by many Amateur radio operators, Es’hail 2, the first geostationary satellite carrying an Amateur radio transponder launched yesterday on a SpaceX Falcon 9 Full Thrust from the historical LC-39A pad in Kennedy Space Centre, which was used by many Apollo and Space Shuttle launches in the past.

Es’hail 2 is the second communications satellite operated by the Qatari company Es’hailSat. It was built by Mitsubishi Electric Corporation (MELCO). It carries several Ku and Ka band transponders intended for digital television, Internet access and other data services. It also carries an Amateur radio payload designed by AMSAT-DL, in collaboration with the Qatar Amateur Radio Society. The payload has two transponders, with S-band uplink and X-band downlink. One of the transponders is 250kHz wide and intended for narrowband modes, and the other one is 8MHz wide and intended for DVB-S and other wideband data modes.

SpaceX live-streamed the launch, and the recording can be seen in YouTube. Today, Space-Track has published the first TLEs for Es’hail 2 and the second stage of the Falcon 9 rocket. Here I look at these TLEs using GMAT.

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Scanning Ku band satellites with the FUNCube Dongle

I’ve recently installed my satellite dish and modified LNBF in my garden. This equipment will be used to receive Es’hail 2, the first geostationary satellite carrying an amateur radio transponder. Here I’ll look at the hardware I’m using, how I did the alignment to the 25.5ºE geostationary orbital position where Es’hail 2 will be located, and how to have some fun scanning the direct broadcast satellites in the Ku band with a FUNCube Dongle Pro+.

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An idea for a low cost stable 10GHz receiver

The satellite Es’Hail-2 is expected to be launched by the end of 2016. This will be the first geostationary satellite carrying an amateur radio transponder. As the launch date comes nearer, it becomes interesting to find a low cost solution to receive its 10GHz downlink.

Several amateurs have been experimenting with low cost LNBFs designed to receive satellite TV. These operate in the Ku band and usually cover the frequencies 10.7GHz-12.75GHz. However, many of these LNBFs have also good performance in the X band, and particularly in the amateur 10GHz band (10GHz-10.5GHz). In fact, the ASTRA-type LNBFs have a local oscillator which can be setted to either 9.75GHz or 10.6GHz. The 9.75GHz local oscillator mixes 10.386GHz (the narrowband terrestrial subband) to 618MHz, which is a frequency covered by most SDRs and conventional scanners. The satellite subband, which is 10.45GHz-10.5GHz gets mixed down to 700MHz-750MHz, a frequency which is also easy to deal with.

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