Wind and Rain Spikes

Very occasionally Weather Station systems, especially those that use cables, can display spikes values that are nothing to do with the weather they are recording. Certainly, and for example, as far as a WS2300/2350 and wind is concerned 57 mph or 92 kph means that the anemometer cable is acting as an aerial.

The source of the RF interference that causes this can be various and near impossible for the average person to determine. It could simply be that the cable crosses or runs parallel to other cables (even those buried in walls), there may be a device locally that is malfunctioning and emitting stray RF, you may be in very close proximity to HT power lines or it could be that the cable is receiving genuine broadcast RF from a transmitter.

There are many possible solutions to this. The simplest if you are a Weather Display user and willing to ignore the visible data on the system console is to use the filters included in the software to ignore the spikes.  Other simple options include relocating the components, re-routing or re-orienting the cables, adding a ferrite core or twisting the cables.

If these options fail then the last and ultimate solution is to replace the cables for all or most of their length with screened cable, in which case CAT 5 network cable is often used. Indeed there is a web site that describes the solution with regard to the wind sensor at http://www.lavrsen.dk/sources/weather/windmod.htm for which the same principle can be applied to the rain collector and direct cable link if need be.

However RF is not the only potential source of interference that causes these and other similar problems. Occasionally earth potential differences between a PC to which the station is connected and the weather station itself can cause problems. This could be down to one of a few reasons but a bad earth on the PC is sometimes to blame. You will usually see instances of this if you connect / disconnect the lead from the weather station to the PC while both are powered up and working. The obvious solution is to ensure that the PC (case, chassis, screen etc.) is correctly earthed. Also a ferrite added to the PC end of the serial cable may well resolve the problem.

We would reiterate that such problems are very rare indeed. They are not restricted to this or any other particular brand or model of weather station. Rather it is the nature of operating any wireless or electronic equipment in our electromagnetically congested world.