Fine Offset WH-1081 Setup and Modifications

[tjaliwalpa]

When I initially installed the WH-1081 on the supplied pole and attached it to a 2 metre upright, I had all sorts of reports of excessive rain that could not be explained. Even when I taped the bucket so that it would not tip, it was still picking up rain. I put this down to interference from the other magnets on the wind sensors, but I have no evidence to suggest this was so.

My brain went to work and worked on erecting a higher pole. I have utilized the full length of the supplied cables that came with the WH-1081. (I havent actually measured the full height of the pole - an oversight on my part).

In addition, I mounted the rainguage at around 1 metre above ground level on a sheet metal box I just happen to have (I know it is a bit of overkill, but it was something I made several years ago and hdan't been using). I mounted my manual rain guage along side the WH-1081 collector so that I could make comparisons and calibrate results.

The unexplained rain guage readings disappeared following these modifications. I still wanted to improve the accuracy of the rain guage readings so I robbed the kitchen cupboard and installed a 14cm diameter funnel, mounted in an inverted Malteser bucket. This bucket fits snuggly over the WH-1081 rain collector making it easy to remove if I ever need to service the sensor. Eventually I want to get a larger funnel so that I get readings as close as possible to 0.1mm accuracy. Currently I use a correction multiplier of 0.66 meaning each bucket tip equates to 0.198mm (close enough to 0.2mm). I arrived at this figure using the manual rain guage placed alongside the modified collector. The figures I am getting match the official figures for our area that come from a station less than 1km from my station.

The rain collector and its calibration are a work in progress. I also wish to add a shield (similar to Hills) over the temperature/humidity/sender unit. That will be essential for the summer months.

Bob

Bob

[hills]

Looks good Bob!! Make sure you keep the old mount for the rain gauge as that makes a perfect mount for your new sheild for the transmitter unit! All you'll need then is the picnic plates and bowls.

[cruisintwo]

G'day Bob,

I'm new to this forum, but I'm sure I'll be visiting on a regular basis.

The first Thread I opened was yours and it answered my problem (I hope)

I have a "Maxkon" Easy Weather WS-1081 which I think is just a re-branded name.

My problem was excessive Rain readings today, 280mm plus. Whilst we are currently in a severe weather warning situation here with Gale Force winds, it has certainly not been 280mm or I would be typing this from my boat. Our local weather station recorded 26.1mm in the same period.

I could only put this down to the high winds we are getting, around the 50 k.p.h. at present. The reason I say this is that in the past I made some adjustments to the pole and on checking my reading found that it had recorded rain during the adjustment, so assume that movement of any kind triggers a reading.

Prior to reading your post I had thought of mounting the rain gauge separately on a non movable structure and surrounding it with a shield to prevent wind from triggering. You have now given me some more ideas.

You also mentioned temperatures. Again I have found this to be a problem. I have tried mounting the sensor in the shade as I could not see how the reading could be correct sitting out in the 'Aussie' sun, at times 48 Deg C. The reading I was getting were vastly different to the local weather station. To correct this I used a multiplier of 0.94 in the configurations and this has me within .2 of a degree.

If you have any other suggestions to get around this, I would like to hear them.

Oops, we have just been issued with a "Flood Advice", but still don't think we've had 280mm!

One question Bob, Is there a need to go to the height you have? Mine is only about 2.5 meters. I did originally have it mounted on the garage roof, so it was about 5 metres.

Thanks again for you post Bob, when the weather improves I'll make some changes.

Regards, Graham

[Gina]

I can answer your question about height of the wind sensors. As high as possible is best up to 10m which is the standard height for wind measurements - at least in this country. I see there is quite a large tree in the photo and my experience is that the turbulence from trees extends further than you'd think.

[hills]

G'day Graham, its good to see more Aussies on here!!

Where have you mounted your temp sensor? I have a mercury thermometre mounted under my eaves and when the sun hits the wall, even though its in the shade it reports much higher temps. Do a search on Stevenson screens, like the one Gina is building, that might be your best option.

[tjaliwalpa]

Graham,

I have made the pole as high as possible as I have trees around my station. I didn't want to extend any higher as it would mean extending the length of the wire as I wanted to keep my rain guage at arounf 1m above ground level - helps with servicing the unit and checking its accuracy against a manual guage.

Regards the temperature sensor, I intend adding a shield as per hills (see hiss post about modifications). I shall be adding a simple solar fan to the modification to circulate air around the sensor. At the moment this is not a priority as we are in winter and direct sunshine for long periods is not an issue.

The rain sensor has behaved itself since the mods. There have been no false readings what so ever, even though we had wind gusts over 50km per hour yesterday. I'm surprised that other owners of this type of rain guage have not experienced more problems with wind. Simply adding a flat plate to the bottom of the guage to prevent wind entering from underneath would be successful.

Must get to work. As hills said, "Great to have another Aussie member". Hope the storms don't do any damage.

Bob