October 2018: Nice weather, good food, bad results
While our 2m equipment is well advanced and has been proven and optimized during the last activities, the higher bands suffered from the accident we had in July 2017 which resulted in the trailer with the 70cm and microwave shack being damaged for good.
Fortunately Henning DF9IC could get a replacement just in time for October 2017 IARU contest and we somehow managed to have everything installed in time more or less. We even finished with very good results, but it had been too much of tinkering and improvisation. It was sheer luck that nothing serious broke and the equipment lasted for the 24h before falling apart.
Haste makes waste, so we took our time in 2018 to have everything installed properly. First thing was to get the roof of the new trailer watertight - which was easier said than done, it needed multiple approaches. And then we had to wait for steady rain to prove the task was completed successfully - which took way longer than expected this year with no precipitation for weeks.
Finally in May we finished the ceiling with new light installation and finished the power distribution during summer. Solid but not too heavy racks for 23cm and 70cm completed the "furniture". Now in the following months all the technical equipment had to be refitted. Obviously we had no chance to have this done in time for July contest (which had to be canceled anyway due to lack of participants on our side), the October IARU contest was the first occasion to try out the old and some new gear.
Weather was great which alone made a big difference to 2017. We started on Thursday at noon at our usual site on Hohloh. One big task usually is the installation of the 8x23 el. 70cm Yagi antenna group at the top of the mast which takes very long, but the antenna never really made a big difference to the three 6x9 el. Yagi groups we have for 70cm usually. So we decided not to install the antenna this time but replace it with a much simpler 4x9 el. group. We planned to mount the three 70cm Yagi groups higher than usual in order to be able to have the 23cm setup still above the constantly growing trees. The mounting equipment we built unfortunately proved to be not good enough. The antenna mast bent heavily, so that the antennas started to get some "elevation"... some improvisation was needed and an improved version was applied on Friday.
Before mounting the antennas we checked them with a small antenna analyzer (N1201SA) we can highly recommend: cheap, small and accurate and works from 2 m to 13 cm. Unfortunately the device showed that one of the antenna groups was not ok. We identified a N connector with a burnt inner conductor on one of the phasing lines and suspected a problem in the matching N jack in the 1:6 splitter. Nothing we can fix on-site. As we could not continue without this being repaired, we ran late already on the first day... Henning took the splitter home and replaced socket and cable connector. So we could finish the 70cm antenna only on Friday morning.
We mounted the 1.6m 13/6cm dish and the 1m 10/24 GHz dish. Unfortunately the rotator position was 180° wrong at first, which would cause trouble with the cable loop around the rotator, so we lost a lot of time correcting our mistakes. But everything seems to work fine. It was for the first time we had 24 GHz mounted directly at the mast; so far we only used the portable transverter from Henning on a tripod from nearby Hohloh tower. But of course it is far nicer to be able to switch to 24GHz with one button instead of having to carry the equipment about 250m and then up 29m through a small stair case into the constantly blowing winds in 1000m ASL on a small viewing platform. The transverter now is a modified Nortel Endwave surplus 24 GHz transverter with about 1W out. Dish feed is a dual-band feed from Hans DK2MN (W1GHZ design) which is supposed to be better than our previous feed and allows dual band operation without having to turn the dish. We lost some more time with wrongly wired XLR cables, but finished testing before it got dark.
A big plus on Friday was lunch: Stefan DL2OCB who joined our team this year not only contributed heavily on the technical side (participating in many working sessions for the trailer and helped finish the microwave transverters and the 24GHz equipment), he also prepared a very delicious goulash. A tremendous improvement compared to our usual 4 day BBQ...
The last thing we managed to do on Friday was to install our usual 23cm antennas: two groups of 6x23 el. Tonna Yagis and two 36 el. Quados. We did however a quick test QSO with Norbert DF6IY and verified that 10 and 24 GHz worked.
On Saturday morning we finished the mast and raised it to its full length. Unfortunately the heavy equipment and the not non-zero tilt angle did not allow to use any spare mast elements, so that the 23cm Yagis were just above the trees.
Setting up everything in the shack including the PAs for 23 and 70cm went smooth. For 13 and 6cm, we now have a "proper" transverter rack in the shack. It will also contain 9cm in the future. Unfortunately the mast box with the PAs and LNAs for the three microwave bands could not be completed this year, so that we still had the 6cm transverter behind the dish only.
We started the contest on all bands in time, but realized already during the testing phase that we had serious problems on 70cm: the west antenna was far too quiet... on the other hand the other antennas picked up really bad noise from about 50° (almost S9). So now the extra antenna on the mast top had to be used to replace the broken west antenna - but unfortunately no way to do anything against the noise. During the contest weekend we tried to find the root cause - the noise signal was definitely not local and did not come from any source in the near vicinity, as it could be received well with our equipment on the mast and also on the Hohloh tower, but not anymore on the parking lot 150m below. Despite our efforts to track the source, we only found it sometime after the contest: the TV transmitter in Langenbrand about 20km away caused our problem because of increased out of band noise! On November 28 its operator had to switch one of the TV channels to a new frequency, and after this change the noise is now gone.
That of course had a huge influence on our performance on 70cm. We tried hard, but we could see in the online score that we were behind DL0GTH all the time. So in this respect our result is acceptable. At the top, everything has to be perfect in order to win the competition...
On 23cm the situation was less clear. Again DL0GTH was leading, but not as heavily as on 70cm. Our equipment worked well, no major problems. If we compare our results to previous years, it was not really bad, but also not great. So maybe the antennas were still too low or some stations did not realize that we are back on the band and did not call us.
13cm and 6cm on Saturday were operated mainly by operators with less experience on our equipment. They did well, but of course Alexander DL2GWZ with all his expertise could do better on Sunday. We finished rather well, but not as good as in previous years. For some reason the 10 MHz OCXO that was supposed to stabilize our frequency on 13cm broke at noon, so that Alexander not only had to fight the usual problems of weak airplane scatter microwave QSOs with lots of QSB, but also had to cope with a huge frequency uncertainty. Good that we have a waterfall display in order to find our QSOs partners quickly.
10 GHz and 24 GHz were also somewhat new to the operators - portable operation and the equipment that we use at DR9A are a lot different. We use OCXO stabilized frequencies and a wide waterfall and SDR to locate the QSO partner easily. An accelerometer behind the dish helps to keep the elevation correct. Some lucky achievements: we worked M1CRO/p on 10 GHz thanks to many, many airplanes on the path between UK and Black forest. Airplane scatter on these high frequencies is really nasty: signals are strong only for few seconds and Doppler changes heavily with the crossing angle of the plane to the direct path. Without the waterfall display of the SDR it would not have been possible to complete the QSO. But after almost 20 min we digged all information out of the many crossing lines on the display: weak CW, but not too bad for 614 km on 10 GHz.
M1CRO/p during 10 GHz QSO:
24 GHz was not so lucky. During the QSO with DL0FTZ we experienced serious problems with the LO of the transverter. It sounded like bad Aurora, SDR showed about 30 kHz wide noise sidebands. Something must have broken. Fortunately the signal was strong enough. We even managed to do some more QSOs, but had to revert to tripod and portable transverter from Hohloh tower for the rest of the crowd, as we could only do CW and obviously not with full power. Due to very good activity we managed to achieve an outstanding result, we claim more than 1200 points! ODX was Thomas HB9JNX on Säntis in 175 km distance (line of sight from Hohloh, we even did 47 GHz as a test in 2017).
47 and 76 GHz were due on Sunday. Unfortunately we lost some time as the team trying to hunt down the 70cm noise got stuck by a flat car battery. So we arrived at the car to pick up the equipment pretty late - just to find out that the support for the transverters had been forgotten at home. But tripods are so overrated: we used the 24 GHz transverter on the tripod as the aiming device and aimed at the corners of the dish. Then Henning DF9IC tried to hold the 47 and 76 GHz transverter in the same direction, while Alexander DL8AAU tried to stabilize the elevation with an electronic inclinometer and find the signal by turning the VFO of the IC202. Not the best way to do 111 km QSOs on 76 GHz, but we completed all of them as usual (thanks for the patience to Horst DL4SBK and Walter DL6SAQ). A test with Ewald DK2DB on 47 GHz unfortunately was negative, he is not far away, but NLOS and we did not manage to find any good reflection point.
We finished tearing down the equipment and packing after the contest rather quick. Already around 20:00 local time we could do the final check on the area that nothing was forgotten and went home.
So we can summarize the contest as nice weather, nice food - and rather bad results. We still had lots of fun and hope to be qrv on all bands more often!
From left to right: Stefan DL2OCB, Michael DK7UX, Martin DL5NAH, Joachim DF1GL, Alexander DL8AAU, Helmut DK8SG, Jens DF5HC, Andrea HB9DUR, Helmut DB1TP, Alexander DL2GWZ, Tim DK5OH, Henning DF9IC