QO-100 Satellite Station

Amateur radio communication via a geostationary satellite

SATGeneral info
Official satellite name: Es'hail-2. The radio amateurs (AMSAT) designated it Qatar Oscar 100 (QO-100).
Satellite built by Mitsubishi Electric Corporation. Weight: 5300 kg
Launched: 15-November-2018 by SpaceX from Kennedy Space Center, Florida, USA.
Amateur radio service was opened on 14-February-2019.

Orbit: Geostationary. Es'hail-2 orbits 35,786 km above the Earth's surface at Equator, and it follows the Earth's rotation. The satellite appears to stand still in the sky. My uplink- and downlink antennas are pointed towards the satellite, and they are mounted permanently (no rotator). The distance from my house in Holstebro, Denmark to Es'hail-2 is 39,171 km.

Transponders: NarrowBand (250 kHz bandwidth), and WideBand (8 MHz bandwidth).
Web-SDR for NB transponder: https://eshail.batc.org.uk/nb/
Web-SDR for WB transponder: https://eshail.batc.org.uk/wb/
More info: https://amsat-dl.org/eshail-2-amsat-phase-4-a


10 GHz downlink:

 
receive chain
Receive chain for QO-100.

Receive chain
The signal from the satellite's narrowband transponder is received on 10.489 GHz. This signal is mixed with the local oscillator (9.75 GHz) in the LNB, and the IF frequency is 739 MHz. The IF is forwarded to the SDR dongle where it is decoded and displayed. The Bias-T supplies power to the LNB while being transparent to RF.

Triax parabolic dish and LNB

Triax offset dish with LNB.

Satellite dish
My dish is a Triax TD78 offset dish; it is 70 cm wide and 78 cm high. It is monted on the wall of my house 2 m above ground. 
Gain is 37 dBi at 11.7 GHz, and the beam width is 2.6 degrees.

LNB
The LNB is Maximum ST-11 single-port LNB. I bought it in a home improvement store (Harald Nyborg).
The LO at 9.75 GHz is phase locked to a 25 MHz crystal oscillator inside the LNB. The frequency is reasonable stable after 30 minutes warm-up.    

Cable
Standard 75 ohm double-screened cable for satellite TV.

Bias-T
Bias-T.
Bias-T
I found the Bias-T on ebay.com. It supplies 12 V 100 mA to the LNB via the coax cable, and keeps 12 V away from the SDR.  
SDR dongle
SDR dongle.

SDR 
The receiver is an SDR dongle from rtl-sdr.com. It is tuned to 739 MHz (NB transponder). The SDR software on the computer is SDR sharp (SDR#).
HP desktop PC
Desktop PC.
Computer
Desktop PC running Windows 10 (64 bit).
CPU is Quad-core i5-2400 at 3.1 GHz.
RAM is 4 Gb.

2.4 GHz uplink:

TX chain

 Transmit chain for QO-100. 

Transmit chain

Yaesu FT-847 transmits on 432 MHz. The transverter converts the signal from 432 MHz to 2400 MHz at 2 W. The signal is then radiated towards the satellite by a helix antenna.

picture Yaesu FT-847
Yaesu FT-847 transceiver.

Transceiver 

My VHF/UHF transceiver Yaesu FT-847 is used for transmitting on 432 MHz. The PSU is a Kenwood PS-30. 

13 cm transverter SG-Lab

13 cm transverter.

13 cm transverter
My 13 cm transverter was made by SG Laboratory Ltd in Bulgaria. The model is TR2300 ver. 1.5. It is delivered assembled and tested from the factory. 

I choose this transverter because:

  • Recommended by other radio amateurs
  • 2 W output 
  • Programmable LO
  • 432 MHz IF
21-turns helix for 2400 MHz
13 cm helix antenna.
13 cm antenna
I'm using a 21-turns helix antenna for the uplink. The product name is Helix-13 and I purchased it 10 years ago at wimo.com. The antenna gain is about 14 dB. Wave polarization is RHCP (Right Hand Circular Polarization). The antenna is pointed directly at the satellite in the sky.

Written by OZ1BXM Lars Petersen 24-April-2019

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