Davis Vantage Vue Weather Station 6250UK fault – no wind speed reading

I have had several weather stations at this location, bought via RadCom, Maplins & the like & none of them have survived long. They don’t seem to be able to cope with the weather! The latest of these is a Davis Vantage Vue. The package including the software had cost about £600, so I was hoping for a high quality station which would last many years.

The wind speed reading has shown zero for some months. I took advantage of the good weather today to take the sensor assembly down and investigate the problem.

It has been installed for two & a half years, so it is outside the two year warranty period now.

The anemometer and temperature sensor board is marked on the top:

Product: #6357OV, Model No. 6250UK, Manufacturing code MK15102 0050.

On the back is a sticker marked: 7345.405, D151012, GF026.

The magnetic sensor is marked: DAVIS 1507.

With the case off I tried and the other telemetry working, I tried waving quite a powerful magnet near the sensor. This produced no reading.

I stripped away the water-proofing from the sensor device. I measured the resistance across it, in situ: 830 ohms.

I put an oscilloscope across the device and spun the anemometer magnets over the device. This produced voltage kicks, both positive & negative! So perhaps the device is a Wiegland wire sensor rather than a reed switch? This suggests that the rest of the rectifier/switching circuit is working.

I checked the receiving station: it showed a wind speed reading!

I put it all back in the box: no reading! I took the lid off the box again and re-soldered the two connections to the device, using a dab of flux & a little extra solder.

 

 

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30-September-2018 UK Microwave Group contest – 3cm

I entered this contest for an hour and worked a few of the usual suspects. Best DX was Nick G4KUX as usual, but we were able to use SSB this time.

25-September-2018 SHF UKAC

Frustratingly, my reference GPSDO refused to fully lock to the satellites, so I was drifting about a bit.

Peter G3PHO & I found our reflection point so he was my first contact on 3cm and the only contact I made to the South of me on this band. Nick G4KUX was my best DX to the North. So just 6 contacts in 3 squares.

I then tried 13cm with the usual 2W. I was pleased to get Brian G8KPD/P in IO85 and out to John G3XDY in JO02. I even managed Neil G4BRK to the South, which is my most obstructed directions from here, so maybe we got a bit of Aircraft Scatter assistance? Mike G8CUL was another surprise.

16 contacts in 7 squares. An 11pm finish is a bit late for me, so I gave up before the end and went to bed.

18-September-2018 23cm UKAC

Conditions were not great. Unusually, I couldn’t hear the Martlesham beacon GB3MHZ, so I was very pleased to find Jon GM4JTJ for my first contact. My second contact was Gordon GI6ATZ, so I thought I had started well. I mucked up the log entry for Gordon, so I lost the points for him.

Towards the end of the contest, I tried to work Pete GM4BYF. This was hard work in the conditions and Aircraft Scatter didn’t help. I didn’t get the points for this contact either.

At the end, I timed out with David G4ASR. IO81 square would have given me 12 squares, so I ended with 11 squares for a bonus of 5,500 points, plus 2,236 for km. I was quite pleased with this given the conditions. All my contacts were within the UK.

1/2-September-2018 2m Trophy contest

Rather than stick with the 4W that usually comes out of the K3, I attempted a fix on a 2m linear amplifier the day before the contest. It is a “30W” Microwave Modules amplifier and I had not used it for so long that I’d forgotten what the fault was. It came apart easily & really there was very little on the board to go wrong. I swapped to two 33uF electrolytic capacitors for higher voltage-rated capacitors & put it back together. With minimum drive from the K3 it produced about 20W out, so fine for this contest. It worked throughout the contest.

There was a bit of a tropo lift and I managed 66 contacts in 29 squares, 19 of them in the UK. The average distance was 245 km & the best DX was DA0FF at 851 km.

28-August-2018 SHF UKAC

I started on 3cm at 1830 GMT running 3W via the circular waveguide to the 80cm off-set dish at 10m agl, 235m asl. My southern-most contact was with Peter G3PHO, via the reflection we have found. This worked well this time. My best DX was Eddie G0EHV/P at 161 km.

I ran 2W from the SG-Labs transverter to the 40 element Wimo yagi antenna. I started 13cm a bit late & gave up early as it was past my bed time. My best DX was John G3XDY at 237km. The contacts were spread over 9 squares. I continue to be impressed at how far 2W can get me.

 

21-August-2018 23cm UKAC

I averaged 130 km/contact,  over 14 squares. My best DX was Jon GM4JTJ. I worked no continental stations.