Es Hail 2 (QO-100) is a new-generation satellite that enables amateur radio communication. The main difference from other satellites is that it is a geostationary satellite orbiting at an altitude of approximately 38,000 kilometers above the Earth’s surface. This provides signal coverage from much of Asia, through Africa and Europe, all the way to South America. Another distinctive feature is the frequencies used. The narrowband transponder has an uplink frequency in the 13-cm band (2.4 GHz) and a downlink frequency in the 3-cm band (10.5 GHz).
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Downlink
The downlink uses a classic setup with an 85-cm offset dish and an Amiko L-107 LNB. This LNB features a PLL and is among the more frequency-stable models. This model was recommended by Vlad OM3CLS. The signal is then fed into a new-generation RTL2832 SDR USB receiver with a TCXO. It has a specified stability of 0.5 PPM and a frequency range of 25 to 1,760 MHz. The laptop is a very old Acer Aspire One with an N270 Atom processor and 1 GB of memory. It’s sufficient for the HDSDR software, but SDRuno stutters.
Uplink
The uplink is transmitted from the TM-455E on the 70 cm band to the SG-Labs TR-2300 transverter, whose output power of approximately 2 W is directed to a PW 24 dBi parabolic antenna. According to the VSWR indicator on the transverter, the VSWR is correct at this frequency. This antenna should measure 107 x 61 cm.
Several QSOs were made with this setup, including HS0AJ, OM3CLS, OM0MS, DG0OPK, and PA3FYM.
Setup
Reception was set up first. Monitoring the beacon strength on the SDR receiver is a great help when aligning the dish. This makes it easy to point the antenna with true precision. The signal from the LNB is very strong, so it’s a good idea to attenuate it before it enters the SDR receiver. There is also some signal drift, but I can’t yet confirm whether it’s caused by the SDR receiver or the LNB. However, based on experience with LEO satellites such as AO-7, VO-52, and FO-29, this is almost negligible.
Signal Delay
Signal delay, however, is significant. Since the satellite is approximately 38,000 kilometers away, the signal must travel twice that distance in total, and this is noticeable. It is practically impossible to hear your own voice because the brain cannot compensate for the delay between the commands it sends to the vocal apparatus and what is received through the ears.
Adjusting the transmit antenna is simpler because the radiation pattern is wider. It’s best to calculate the elevation and set it using a protractor, and then just fine-tune the antenna. Since reception is already working, you can adjust the antenna based on the transmitted carrier. By fine-tuning, I managed to improve the signal strength by another 2 dB.
Using a Power Amplifier
Some stations also use a power amplifier (PA). The so-called WiFi PA EP-AB003 is available and can be purchased at a reasonable price. The achievable power output is 3 to 4 W. Even so, you need to be careful with these PAs to prevent possible overheating.
Another option is to use modified amplifiers from professional transmitters.
Conclusion
QO-100 is a very interesting project that makes satellite operations accessible to many amateur radio operators. For me, it also represents two new bands that I haven’t operated on yet. I believe that the entire setup will gradually be improved, and JN98av will be a permanent presence on this satellite. Give it a try, too!