W8681 - You get what you pay for

[bluebeard]

It is rapidly becoming obvious that the 8681 is really the sum of its parts. I am becoming quite disappointed at its overall performance.

Its now obvious from reading the forums and using the unit, that 'you get what you pay for'.

The unit itself with an identified flaw of poor contrast, remains with the problem seeming unaddressed.

A rain collector that should be mounted on something solid and away from any vibrations and wind buffetting.
Hence the inclusion of a large length of cable and two screw fixing lugs on the base. Yet it omes with instructions to mount on a pole.

A wind vane that should be better damped and not be quite so influenced by its surroundings and should stay on the pole but at at the highest point it can be mounted together with the anemometer.

The baro, DCF and temp sensor can stay on the pole.

I can see now why my last setup some years ago of Oregon wireless set up was so expensive. The 8681 is not a patch on it.

So having come to the realisation that I have shelled out on not much more than a toy,
I can still take comfort in the fact that I may treat myself to something a little more sophisticated on santas list and it will still mean that I can run it with CUMULUS which is the best thing to come out of the whole experience

So should you venture to have a look at my little site offering - take all the readings with a large pinch of salt. Not the fault of Cumulus, it reads what it's sent (Maybe I should include that on my index page?)

Thank you - rant and moan over.......

[dc1500]

My experience is slightly different.
I do agree with you that you get what you pay for but I think for £69 it has brought PC logging and website ability into budget for a mass market of weather hobbyists. You could previously only just get a temperature logger that links to a PC for this money. I am finding that with a few mods to the shielding the temperature to be very accurate, and the barometer great. I agree about the windspeed and wind vane but I am not that bothered because few more expensive set ups are accurate due to poor siting anyway. I have a standard raingauge to calibrate with which can then be done in Cumulus to good effect. Mine is pretty stable and at least tips every 0.3mm. My Oregon with a 1mm tip tends to be a bit low.
The contrast is poor but I rarely look at it now with Cumulus. (Mounted vertically does improve things a lot)
I have nothing to compare with but it is a bit plasticky so how long it will last I don't know.
I guess in the end its like trying to compare a Nissan with a Rolls Royce - depends on what you want it for and what you want to pay!
Dave

[philcdav]

eh up Bluebeard. i think your very harsh.

Its a pretty good bit of kit compared to whats gone before versus price.

Applying Alan Sugars' rule of 'cost = 4% of retail price' we have a fairly complex kit @ £28

You would be hard pressed to make the same.

OK, its got issues with hard and software but its all good fun at an affordable price.

And i will bet that its beeing modded/hacked as we speak and will do all sorts in the future.

Regards - Phil (G0DOR)

[bluebeard]

Yep I agree. But it has no business as being described as professional. It is as was described earlier as merely an interface between the instruments and the internet. Like I said the best thing that has come out of it for me is Cumulus, I am having more fun tweaking and modding that that anything else

[goldrush]

My experiences with the Fine Offset stations (WS8681 and WH1081) is that you may actually get a station better than some of the dearer ones....... depending upon circumstances, albeit obviously of "poor" mechanical quality!

I purchased a La Crosse 2350 and had nothing but problems, eratic, incorrect and lost data, periods of inactivity etc, both when it was used as a "radio link" and as a wired system.

After 2 new systems gave very similar problems, even when modified to use cat5 cable between units I obtained a refund and purchased a cheapo WH1081 (same unit as WS8681).
Because of my installation, I needed to extend the data lead from the anemometer to transmitter by 50 metres and so far unlike the La Crosse absolutely no problems.
However, as previously noted the rain guage does need to be solidly fixed, otherwise when it is windy, it thinks it is raining.... this was also exactly the same problem with the La Crosse.

Originally I too had problems with the wind direction vane acting like a helicopter, on both the La Crosse and the cheapo due to turbulance from nearby roofs, but installing the anemometer at close to the officially recommended position cured it.
It is now pretty steady and directionally accurate, following closely a windsock I also have.

I do accept that they are nowhere near the Davis etc.

[bluebeard]

I may have done the kit an injustice to a certain degree My wind instruments are far from ideally sited, on a decent pole in my back garden but surrounded by other properties which give rise to some very variable readings due to turbulence. I read somewhere that the ideal height for wind recording kit is in the clear above 33'. Well I ask you - just how am I expected to change the batteries

As the well know phrase or say goes - keep ******* in !!

Its all in fun like most hobbies of this nature, its not the result that counts - its how many Robinson H's are involved in the excecution.

[keithatrochdale]

..........wind recording kit is in the clear above 33'. Well I ask you - just how am I expected to change the batteries

Modify the unit by adding some wire to the two battery connections and use a remote battery box at a more accessible height.

[dc1500]

I was interested to read that the cable could be extended to 50 metres. This would allow separate and optimal siting of the anenometer. No need to worry about changing the batteries which are situated in the central unit where the temperature sensor, rain and wind connector sockets are. In fact the included pole could be redundant with the temperature in a screen and the rain gauge somewhere suitable with another extension if required.
Dave

[goldrush]

I have added a bit more info on lenghtening the cables under the "what mods have you made" thread.

[goldrush]

Re anemometer siting.
To quote from one official standards document.

Simple Anemometer standard:

 10 meters (33 feet) above ground level (AGL).
 If there are obstructions above 8 meters, anemometer should be at least 2 meters (7
feet) above obstructions (trees and/or buildings) that are within the immediate vicinity
of weather station (20 meters horizontally).
 Anemometer mast should be absolutely vertically level.
 Anemometer should be orientated to yield wind direction values from “true north”

However, the standard for agricultural application is to place the anemometer 6' (2 m) above the ground. This is important for evapotranspiration (ET) calculations

Rain guages

The unseen danger involved in measuring precipitation is exposure of the rain gauge to
winds greater than 5 mph (2 m/s) at the height of the gauge orifice. As wind speed
increases, rain is carried up and over the leading edge of the rain gauge resulting in a loss
of total rainfall measurement or undercatch.
The leading edge of the rain gauge orifice deflects the
wind over the gauge causing the resulting turbulent flow to carry precipitation
substantially over the gauge’s orifice
A good rule-of-thumb is the rain gauge location should be no closer than half the height of tall
objects, e.g. a 10 ft tall wall should be no closer than 5 ft distance from the top of the rain
gauge to the base of the wall

[dc1500]

A plus point for the temperature measurement is speed of response (compared to those in screen). This is particularly useful at the moment in the UK where we ar having temperatures of 10C in the sun with a rapid drop as showers pass through. i realise this is due to exposure and not sensor (probably) but I suppose it is one advantage of the pole mounted set ups.
Dave