October 2014 UHF Contest

Well that didn't go too well....

Everything started out OK (apart from the weather - rain and wind in the first few hours) but then the 23cm masthead preamp decided it would give up the ghost after a couple of hours. It is the first preamp I have lost in over 35 years! I don't know exactly what has happened to cause it, at this stage I know the gain has dropped from 30dB to 6dB and the NF is now 5.7dB With the rain and then darkness falling I decided not to try and fix the problem until Sunday, so concentrated on 13cm and upwards on Saturday evening. Sunday was cold but sunny, after taking the tower down I found that the screws holding the lid on the preamp box had seized, so the whole box had to come off the mast for some serious attention with an impact screwdriver. This eventually worked, and I replaced the preamp with another one with less gain. Having wound the tower back up again I found this one was very deaf too (it looks like the antenna relay was not switching to receive), so gave up. I eventually wound the tower down again to reconfigure the system to reduce feeder loss on 70cm and reconnected the 70cm preamp (the 70/23cm preamps share a receive feeder via a diplexer filter), and finished the contest operating exclusively on 70cm.

Conditions prior to the rain front arriving weren't too bad, but it started raining just as the contest started, and conditions were back to normal. However the usual aircraft reflections helped achieve some good DX. Later during Saturday evening the rain front provided some fairly good rain scatter into PA and DL on 3cm and 6cm.

On Sunday tropo conditions were a little up over local paths early in the day, but then fell back to normal. Aircraft scatter was the order of the day, luckily DL0GTH had the time to wait for the right planes so we could complete QSOs on 9cm and 6cm. I heard DL0GTH briefly on 3cm, but the reflections were too short to make a QSO, however I managed an easy aircraft reflection QSO with DC6UW on this band, thanks to Norbert's QRO system. The last hour or so on 70cm was mainly used for aircraft scatter QSOs.

One good thing was that the revisions to the 3 and 6cm systems worked well. The relay logic used for bandswitching has been replaced with CMOS logic and power MOSFETs, and the LOs on both bands are now locked to the GPSDO 10MHz reference using the DF9IC PLVCXO design. This made frequncy setting very accurate and finding other stations was easier even when they were very weak.

73

John G3XDY

Results:

Band (MHz)

QSOs

Claimed Score

Best DX

Locator

Distance (km)

432

49

20905

OK2A

JO60JJ

827

1296

26

8719

DF4IAO

JN48WM

731

2320

23

7064

DL0GTH

JO50JP

684

3400

11

3726

DL0GTH

JO50JP

684

5760

9

3000

DL0GTH

JO50JP

684

10368

19

5701

DC6UW

JO44VJ

627

 

 

 

Back

Home