DR9A  JN48EQ
 
Team
 

July 2012: a visit from Mr. Murphy

"What happened in May?", you may ask. - Well, we would have liked to join the fellow contesters, but our QTH was not available during the weekend because of a local event. So some of us made a visit to DL0GTH and enjoyed the abundant rain in JO50, and the rest had to wait eagerly for the July contest weekend.

It started already with a problem on Friday morning. The ground was wet through the rain the days before, and Henning could not pull out the trailer from its parking place, his car just burrowed into the mud. So the tall Helmut (DB1TP) had to come with his 4WD and help. Before we really had started we were already two hours late. - At least the weather improved, and the rain stopped in the early afternoon. The 144 MHz antennas were up around 6 o'clock, 70 cm was ready less than 2 h later, and the late dusk allowed us even to put up 23 cm the same day. We tested all receivers, which worked well, so we were happy. The mosquitos around us, too.

By the way, only three weeks earlier we got to know that Hans DF2UU who did support us for years with a WLAN access had to take down his antenna, and we were left alone. We found a possible link path to Klaus DJ7UD, bought new 5 GHz equipment, and installed and tested it successfully 10 days before the contest, using the nearby viewing tower as the test site. But the new link is tight, with a hill in the mid of the path ranging into the Fresnel zone.

On Saturday morning we pushed up the mast to its full height. It looked quite sloping though it had gone up smoothly - but we left it as it was. Then we found that we should have tested the full setup better before - the 70 cm TX cable was open circuit. Alex DL8AAU inaugurated his new climbing harness and found the connector of the cable not well fixed to the T/R switch box - one more turn of the union nut, and the VSWR was down as it should be. The weather on Saturday was nicer: dry and partly sunny. And we could welcome Alexander DL2GWZ as a new member.

We opened the contest in time. The activity seemed to be a bit low, but at least everything worked. Until about 8 o'clock - then a similar high VSWR problem occured on 144 MHz. Again something in the switchbox or even on the antenna, which in this case means at least 30 m above the ground. It was the main antenna which didn't work anymore. - This time Suad DK6XZ volunteered, climbing around all the other antennas to the top of the mast. And what a déjà-vu - again the connector of the TX cable was bad, it had even broken off the 1/2-inch hardline. We replaced the line by a 25 m long H2000 cable that is lightweight enough for Suad to pull it up, and then extended it by a 7/8-inch hardline in the lower part. About one hour later we could restart operation. During part of the repair time 70 cm and 23 cm had to stop too.

Enough problems for the day? - No, Mr. Murphy returned. The internet connection which had worked reliably since Friday evening started to freeze, and monitoring its signal strength we found it had dropped by more than 10 dB and was only marginal. We lost the connection to KST chat during the whole night; no skeds for 23 cm.

Some frustrated OPs went to bed and were aroused from sleep the next morning by heavy rain and a thunderstorm. The morning shift had to stop operation for some period of time, in order to escape into the cars as a safe place. Our mast is the highest point in a 15 km circle. But later - around 9 o'clock - the rain declined, and even the WLAN link recovered by itself.

Around noon Oli DK1CM came out of the trailer, reporting the 70 cm PA did not work any more. The mains fuse for the HV PSU was out - after resetting it the PA returned to normal operation. Better to say... nearly normal operation, it started to smell. This continued for some 15 minutes, then the PA gave no more power, and it was time for a repair. When the lid of the HV PSU was open the problem was easily spotted by the nose: the little 6.3 mm fuse in the HV circuit had exploded and burnt out during the first event - maybe caused by an insect in the cavity - and the fuseholder was split into two parts. It still gave some contact for a while, slowly burning down more and more. We had a replacement fuseholder in the inventory - it was not the first event of this kind - and repaired the PSU; 30 minutes later the operation resumed. But the band stayed too quiet.

Our result is less than satisfying - on all bands we reached less points and QSOs than last year, with 70 cm being exceptionally worse. Part of the loss results from the mentioned problems but there is more to improve than just the reliability of the equipment. We feel the challenge - our competitors did better than us.

The good point at the end was the weather. The Sunday evening showed a sunny blue sky, and it is always nice to leave the place in dry clothes, with dry material and in a good mood.

We'll be back in the autumn - hopefully stronger than ever. - Mr. Murphy, please stay at home or visit someone else!


Saturday late afternoon the weather was really beautiful.


No - this is not the lens distortion...

DL2GWZ: don't disturb me - there is DX on 23 cm.

Mast climbing part I: DL8AAU repairs the 70 cm TX cable.

Mast climbing part II: with the last rays of the sun, DK6XZ on his way to the top....

... and there he is.

Is the WLAN dish still in position? - picture taken through the trees, around midnight, illuminated by a LED torchlight on 50 m distance, handheld 300 mm 1/5s ISO 12800.