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.
Currently, we are preparing the new tower base plate on the roof of the institute of telecommunications. The existing base platform requires some re-enforcements before the new tower can be mounted. On December 7, three additional steel beams were welded into the base platform.
Dear contest fellows!
the Radio Amateur Club of the TU Wien participated in this year’s CQWW CW Contest on the 160m band only. We used 5W of transmit power and entered the contest as a QRP station. We hope your callsign is in our log and OE1XTU is in yours, 73 de Chris, OE1VMC / OE1XTU
Since July 11, 2017, beta releases of WSJT-X, version 1.8.0 are available for Windows, Linux and Mac. MNI TNX to OMs Joe Taylor (K1JT) and Steven J. Franke, K9AN, and all the WSJT-X developers. Version 1.8.0 introduces the new FT8 communication mode, featuring a four times faster turnaround than JT65 and JT9. FT8 transmissions are decodable down to –20 dB. The loss is 6 dB compared to the slow JT-modes and this is easily compensated by QRO +6 dB. (FT8 techie details here in German)
screenshot source: K1JT
On the HF-bands, FT8 has since tremendously taken off and OE1XTU didn’t want to be left behind. Our first QSO OE1XTU–IZ2GNQ completed in FT8 on August 16, 2017. Even the ADIFF spec has been updated already, as well as LOTW, eQSL, and QRZ.com. Students taking part in the Short Wave Communication course at the Institute of Telecommunications, TU Wien, will have a first hand look and feel in a couple of weeks. 73 de Chris, OE1VMC / OE1XTU.
During the Spring term 2017, Andreas, Thomas, and Beatriz designed and manufactured the WR90 feed horn for a 57cm diameter parabolic dish. This was their project task in the course Antenna Design and Realization (389.104). Their feed-and-dish X-Band prototype was also used by them for the propagation measurements in the sister course Centimer- and Millimeter Waves (389.190).
In the anechoic chamber
Yesterday, Andreas and Thomas characterized the X-Band prototype antenna in the shielded anechoic chamber of the Institute of Telecommunications. To prepare the measurements, a mechanical adapter was fabricated before hand. Prof. Arthaber explained the principles of antenna characterization in the near-field and guided them through the measurement process.
Antenna pattern in azimuth and elevation
Waiting for the measurement to finish
Preliminary analysis of the measurement indicates a directivity of 34 dB and sidelobe rejection better than 40 dB. Congrats! 73 es GDX for upcoming real-world contacts
On May 24, 2017, two student groups at TU Wien set up two transceivers for X-band operation (10368-10370 MHz). See fotos below. The first task in the practical part of the course „Centimeter- and Millimeter Waves“ (LVA 389.190) is to integrate all components (YAESU FT-817ND, Kuhne 10 GHz Transverter, 57cm parabolic dish, WR90 feed horn, coaxial relays) into a working prototype. The first real-life test is the reception of the OE1XGA beacon located on Kahlenberg north of Vienna city. Second test was a bidirectional voice link in SSB modulation. Mission accomplished. Next tasks will be measurements on the antennas, link budget, diffraction effects of a plate, and oscillator stability, … and comparing those with the predictions from theory.
40m Monoband Dipole
The Radio-Amateur-Club of TU Wien, OE1XTU, participated in the All Austrian Contest 40m/80m on May 1st, 2017, with the team: OM Gerald OE1GAQ, OM Dieter OE8KDK, OM Stefan OE1ABU, OM Stefan OE1SCB, SWL Horia, and OM Chris OE1VMC. This year, we used only Inverted-V dipoles and 100 W of transmit power. Our 160m/80m/40m fan dipole covers North-South, whereas the newly erected 40m monoband dipole covers East-West directions. Propagation conditions were very difficult on 40m during the contest. The map above shows that we could only reach a few stations in Eastern Austria on 40m from our QTH „Wien City“ AND VORARLBERG (!), but none in between. Almost all contacts were made on 80m alone.
See also the article „Old Men senden öfter 73 aus Whiskey Charlie“ in Der Standard – FORSCHUNG SPEZIAL on May 3, 2017 (in German language).