Davis Classic Station Accessories

There are various classes of accessories available for Weather Wizard III stations:

• Radiation Shield;
• Extension cables;
• Protection from Electrical Surges etc
• Others (eg Mounting Accessories);

NB These are accessories for the station hardware itself. The 7862 Weatherlink data logger and software is of course also available for the Wizard station and provides the general features available from all Davis loggers.

If you buy no other accessory, this is the one we would really recommend! Its purpose is to protect the temperature sensor from being exposed to direct sunlight, which inevitably causes the sensor to heat up above the ambient air temperature and then results in temperature readings that are too high. (If you don’t have a shield and wish to obtain correct temperature values then you must mount the temperature sensor such that it is always in the shade.) Of course you may already have a suitable shield or might be able to make a DIY shield that allows free circulation of air, but the Davis shield is designed specially for the job.

The Davis shield is supplied in easy-to-assemble flat-pack form and is designed also to accept the combined temperature/humidity sensor, preventing rainwater reaching this sensor in addition to protecting it from direct sunlight.

Because each sensor fitted to WWIII type stations is individually cabled back to a junction box, a number of different extension cables are available to provide flexibility with the cabling configuration.

The cable runs associated with WMII type stations are shown in the diagram to the right. Each of the three possible outside sensors (anemometer, rain gauge and temperature sensor) is cabled separately back to a small junction box, which is designed to be located indoors. All of these cables are 4-conductor cable. A short (2.4m) length of 8-conductor cable then connects junction box to console.

Each outside sensor is supplied fitted with 12m (40′) cable, except for the temperature-only sensor of the Wizard standard stations, which has only 7.6m (25′) fitted. Any of these cable runs may be lengthened with Davis extension cables up to certain specified maximum distances from sensor to console (enquire for details), which  are available as follows:

• 4-conductor: 2.4m; 12m; 30m; 61m;
• 8-conductor: 7.6m; 15m; 30m;

Important Each extension cable is supplied with two different types of connector to allow it to be linked to an existing cable. Whichever type is used, care must be taken taken to fully waterproof any cable junction exposed to the weather.

The multiple cable runs of a Wzard type station can occasionally act as aerials which can pick up electrical surges caused, for example, by lightning strikes in the neighbourhood. They may also pick up interference due to any kind of nearby transmitter (either a radio transmitter or any other source of electrical interference such as fluorescent lights) and cause the station to display and store incorrect readings on occasion. We do recommend that the mains adapter on WWIII stations is attached to a mains surge suppressor that also explicitly provides RFI (Radio Frequency Interference) elimination in order to reduce any mains-borne interference, but there are three particular Davis accessories that can also be fitted to minimise non-mains interference and surges:

Protected Junction Box

This is a replacement for the standard small junction box. It has active elements that can shunt down to earth sudden electrical surges that might be picked up by the outside sensors and will also help to reduce the effects of airborne interference. Note that at least one wire from this unit must be connected directly to a good earthing point for best results.

Surge Protectors

These are specialised elements that provide upgraded protection against voltage surges such as those induced by nearby lightning strikes. Each element can protect two conductors in a cable and therefore multiple multi-conductor cables will require several element for full protection. The surge protector elements fit into a small or large surge protector shelter. The small shelter takes two elements and can therefore protect a single 4-conductor cable. The large  shelter accommodates twelve elements. Note that stripping of the cables is required to install these protectors.

PC Link Isolator

This is a small mains-powered unit specifically for WWIII stations connected to a PC via the Weatherlink data logger. It is placed in the cable between data logger and PC and provides complete electrical isolation between the two – data is passed on only via an optical link. This isolator therefore removes any possibility of electrical interference or surges passing from weather station to PC and is also useful for preventing the phenomenon of ground loops that can sometimes occur when another piece of electrical equipment is connected to a PC, especially a portable PC. The Isolator is supplied with 12m cable, which means that no further extension cable is needed if the PC is to be placed at some distance from the weather station.

While it is perfectly feasible to mount all of the outside sensors using simple DIY mounting points, such as wooden fence posts or an existing TV aerial mast for the anemometer, Davis do provide various mounting accessories that can make sensor installation quicker and more convenient. The 7716 Mounting Tripod and 7717 Mounting Pole kit are described on the Vantage Pro Accessories page.

Please enquire about other WMII compatible accessories that are also available, including:

• Display repeaters;
• Weatherproof shelters for housing console outdoors;
• Solar power kit;
• Rain collector and shelter heaters;