New mode FT8 in WSJT-X

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 OE1XTUIZ2GNQ completed in FT8 on August 16, 2017. Even the ADIFF spec has been updated already, as well as LOTW, eQSL, and 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.




X-Band Dish Characterized

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).

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.

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


CQ CQ on 3 cm!

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.

With 100W and a Wire @ AOEC 2017

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).

Preparing for All Austrian Contest 80/40m


Every year, on May 1st, the Austrian Amateur Radio Society (Österreichischer Versuchssenderverband) organizes the All Austrian Contest 80/40m which also serves as an exercise for emergency and disaster relief radio services. Alas, our work horse, the SteppIR DB36 Yagi-Uda antenna for 40m-6m is currently under repair and the Inverted-V antennas for 80m and 40m cover mainly a North-South direction. Not exactly, what we would call an ideal outfit for the contest.

On April 25, we therefore hastily erected a second 40m monoband inverted-V antenna with look direction East-West on the roof of the Institute of Telecommunications.

The OE1XTU contest team for AOEC 2017 consists of Dieter OE1KDK, Stefan OE1SCB, Stefan OE1ABU, Gerald OE1GAQ, and Chris OE1VMC. Wishing all radio friends great many contacts and a lot of fun in the heat of the contest.

X-Band activity in 2017 with dish

imageThe 10 GHz rover station OE1XTU will be upgraded with an offset feed dish, 57cm diameter in May. See the mockup of the new setup on the photo above: just the feed horn and the coax relais for Tx/Rx frontend switching are still missing … the feed horn will be designed and manufactured by a group of students in the elective course „Antenna Design and Realization“ (LVA 389.104). The rover station itself is used in the elective course „Centimeter- and Millimeter Waves“ (LVA 389.190).

Teaching Short Wave Radio

In the winter term, the Radio Amateur Club of the TU Wien supports the elective course „Short Wave Radio“ (LVA 389.030) in the practical part where we go „on air“. Here you see OM Stefan OE1ABU operating the club station OE1XTU while talking to OM John OF2K in Finland on the 40m band. His fellow students are fascinated, but (still) unlicensed.


All radio contacts of the OE1XTU club station are logged and archived electronically since the early 1980s. Below, you see an excerpt of the club’s logbook for all radio contacts made on January 19, 2016 during the course. Contacts were made in both analog (SSB) and digital modes (PSK31, PSK63, and JT65).


Balun replaced, dipoles repaired

Heavy winds destroyed the N-connector of the elderly balun feeding our 40m/80m/160m triple band dipoles during December 2016. Foto of the newly installed balun and the corresponding VSWR measurement below. GDX de Stefan OE1ABU and Chris OE1VMC



X-Band Scatter-Link via Schneeberg

On Dec. 29, 2016, interesting microwave QSOs were in the air: Mike, OE3MZC was on air as OE16YOTA on the 3cm band from Buchbergwarte (Locator:JN78xe). Gerald, OE1GAQ and Stefan, OE1ABU activated OE1XTU (QRG 10.3681 GHz, 250mW, 16dBi horn antenna) on the roof of the Institute of Telecommunications, see fotos below. Other stations heard by OE1XTU: OE1TGW/1 and OE4WOG/p. Below you see Gerald, OE1GAQ and Stefan, OE1ABU while listening to OE16YOTA in SSB using the Schneeberg as scattering object. Although OE1YOTA was clearly heard, a QSO with OE1YOTA was not accomplished. At least one QSO with Gerhard, OE1TGW/1 was completed. Next time better using directive antennas with significantly larger gain.