Two students have designed and manufactured a quadrifilar helix (QFH) antenna for the 70cm band as their project in this year’s course „Antenna Design and Realisation“. The antenna is mounted on the platform of the satellite ground station at the roof of the institute of telecommunications.
The QFH antenna will support the PEGASUS satellite mission which is a 2U CubeSat with two redundant transceiver modules. Two 90° crossed dipole antennas are used independently by the two transceivers on-board. Carrier frequency for the downlink telemetry data is 436,670 MHz.
In the course Antenna Design and Realisation (389.104) students first simulate and then build a directional antenna for the 6m band. The Yagi-Uda design with 6 elements follows recommendations published online by Ljubisa Popa, YU7EF. When ready end of June 2018, the antenna will be mounted on the tower and thoroughly tested .
For May 30, 2018, the members of the radio amateur club of the TU Wien were invited to the club’s general assembly. This includes a roof visit (foto below), antenna and shack inspection, report from the board about the past two years, future planning, as well as an invited talk by Emir OE1EMS on his contest station E7DX and the election of the new board members. The newly elected board members for the next two years are Stefan OE1ABU, Gerald OE1GAQ, and Chris OE1VMC. After the official part, the discussions on antenna technology, contesting, the future of ham radio, continued in a local beer garden.
The geographical map shows in detail which of the districts we were able to work. Blue districts indicate a contact on 80m, green districts indicate a contact on 40m, red districts indicate contacts on both bands.
This year, we have logged 267 contacts. The table below summarizes our recent AOEC statistics which reflects the effects of the solar cycle. In 2017, the SteppIR DB36 was unusable which explains the very low number of QSOs on 40m.
It’s time to party: Our SteppIR DB36 Yagi is repaired and mounted on the new T50C tower. It took only 18 months to get this done since the storm in early December 2016: construction planning and oversight (Bertram Menth), paper work, procurement, delivery of parts, more paper work, welding of the new tower base, roof insulation, and finally: putting it all together with the helping hands and ideas of Emir E77DX, Gerald OE1GAQ, Stefan OE1ABU, Arpad OE1SZW, Dieter OE8KDK, Stefan OE1SCB, Chris OE1VMC. Not to mention organizational support from TU Wien GUT (Konrad Holluger, Gerald Hahn, Astrid Steiner, to name a few), financial support from the faculty (TNX to Markus!). We will throughly test the setup during the All Austrian Contest 80/40m AOEC 2018 on May 1st, 2018.
On Feb 1, 2018, the faculty of electrical engineering and information technology invites to its annual open day event for school children. Apart from presenting the bachelor curriculum in EE and IT, we also offer lab demos. This year, the radio-amateur-club demonstrated low power terrestrial voice links in the X-band at frequency 10368,1 MHz or approx. 3cm of wavelength. Many thanks to Gerhard, OE1TGW, and Wolfgang, OE4WOG, who setup their X-band equipment on Bisamberg and Burg Forchtenstein for this demo, respectively. Have fun with the 10G phone!
Every 3rd weekend of the month, the Austrian microwavers experiment with propagation and technology at 1 GHz and up. The so-called microwave activity contest takes place on Sunday mornings. The fotos below shows the experimental setups of OE4WOG/P (left) and OE1XTU (right) used on 21.01.2018 for a 10G phone contact. Wolfgang, OE4WOG/P, has setup his rig on a parking spot of Burg Forchtenstein, some 56 km south of TU Wien (see the map). Link parameters: frequency: 10,3681 GHz, polarization: horizontal, modulation: SSB, bandwidth: 3 kHz, link distance: 56km. Transmit power of OE1XTU: 0,26 W, antenna directivity of OE1XTU: 34 dB, resulting in approximately 28 dBW EIRP.
This year’s short wave radio course at TU Wien had 16 participants. We had fun on the longer bands: 160m / 80m / 40m using dipole antennas and a potpourri of modulation formats.
First agenda item in the practical part of the course is the chilly roof visit with antenna inspection. See foto below right.
After we returned to the shack, we experimented with a freshly built Lima-SDR and the SDRadio software on a PC. AM broadcasts can be demodulated with a variety of techniques: the non-coherent envelope detector, the phase-locked product detector which is also known as Exalted-Carrier Selectable-Sideband (ECSS) reception, as well as Upper/Lower Sideband demodulation. These four techniques aren’t equivalent and they sound audibly different.
Finally, we went on air using the OE1XTU club station. Chris, OE1VMC, and Gerald OE1GAQ, worked several stations in CW, SSB, PSK and FT8. 73 es gd dx!
During January 2018, the students in the short wave radio course will compare the reception fidelity and sensitivity of Lima-SDR (Foto) with the YAESU FT-2000 Radio in the OE1XTU Shack. Lima-SDR Receiver Sounds quite good in the preliminary tests so far.