onsdag den 1. maj 2019

Transmitting via Es'hail-2/QO-100 geostationary satellite

Transmitting via QO-100 was easier than I thought. The transmit chain is shown below.
TX chain for satellite QO-100.
A 70-cm transceiver was already in the shack. My trusty old Yaesu FT-847 is still doing well. The FT-847 output was reduced to 3 W on 432 MHz.

Yaesu FT-847 transceiver.
I needed a 13-cm transverter for the uplink. I choose to buy a ready-made one from SG Labs in Bulgaria. It was delivered assembled and tested from the factory. Time from order/payment to delivery was 6 weeks. The transverter provides 2 W output at 2400 MHz which is sufficient for making contacts on the satellite.

13-cm transverter from SG Labs.
The QO-100 uplink signal should be circularly polarized. 3 dB is lost if a linear signal is transmitted. I decided to employ my 10 year old helix antenna with 21 turns. I had to adjust the bracket so the antenna was elevated 24 degrees (this is the elevation of a geostationary satellite seen from central Denmark).

Helix antenna for 2400 MHz. Elevation is 24 degrees.
I was happy to learn that my transmit signal was visible (and audible) on the waterfall display. I had my first QSO via QO-100 on April 24th. 

The QO-100 narrow-band transponder can be monitored via this web-SDR: https://eshail.batc.org.uk/nb/

73 from OZ1BXM Lars
Homepage: http://oz1bxm.dk/