Choosing a weather station model – frequently-asked questions (Legacy)

This page is now considered outdated as the information has not been updated in sometime and is no longer relevant to the current Davis systems. This page has been left as a reference page in our ‘Legacy’ section.

There are obviously quite a number of factors to consider when choosing a new weather station – your own detailed weather monitoring requirements, available budget and so on. On this page you’ll find answers to some of the commonest questions to help guide your decision-making.

The two major questions – assuming that you’re interested in the market sector covered by Davis stations – are:

• Which line of stations to focus on?
• If the Vantage Pro 2 stations are of prime interest, whether to opt for the cabled or wireless VP2 model?

Beyond these two initial choices, there’s a set of more general questions and answers below that provide some further background information on the practicalities of choosing and setting up a new station.

The information here should provide a good starting point to weigh up the pros and cons of each station type against price. But remember that we’re also more than happy to answer specific questions by phone (03336 664175) or by email for anyone considering buying a station from Prodata Weather Systems – we do appreciate that although we’ve tried to make the advice here as accessible as possible, the amount of detail available may possibly still seem a little overwhelming if you’re not familiar with weather station terminology.

There are two current families of Davis stations:

• Vantage Pro 2;
• Vantage Vue;

(Some existing Davis users may also be familiar with the older and more basic Davis designs named Weather Monitor II and Weather Wizard III, but these stations were discontinued some years back and are no longer available.)

The primary decision clearly lies in choosing between the Vue and the Vantage Pro 2 stations. First, some similarities: Both Vue and VP2 stations are able to measure the same six primary weather parameters as standard: wind speed & direction; air temperature; relative humidity; pressure and rainfall. The Vue and VP2 can also both optionally be fitted with full data logging and data upload (eg to websites) capabilities. And both Vue and wireless VP2 models use exactly the same wireless protocol, so allowing the same wireless repeaters to be used to extend wireless range and the same Vantage Connect unit to be used to provide a 3G data link.

But beyond these common features, the two model ranges diverge considerably with the Vue being a single basic model, while the VP2 is a large family of models, each with a different mix of features and sensor options. The chief pros and cons of the Vue and VP2 stations are as follows:

Feature	Vantage Vue	Vantage Pro 2
ISS-to-console data link	Wireless only	Choice of cabled or wireless models
Outside sensor assembly	Single integrated unit	Anemometer can be mounted separately
Built-in Radiation Shield	Passive only	Fan-assisted as an option
Solar/UV sensors	Not available	An option on all VP2 stations
Supplementary Sensor Stations	Not available	Optional on wireless VP2 models
Enhanced temp/hum sensor	Not available	Optional on all VP2 models
Console text forecast	Not available	Standard on VP2 console

So the Vue is clearly the more affordable station but is correspondingly much more limited in flexibility and in sensor and expansion options. The Vue is therefore ideal for users seeking a straightforward and real value-for-money solution to weather monitoring in situations where it is acceptable for a standard set of outside sensors to be located in a single assembly. But for anyone seeking to add extra sensors – or at least to have the option of doing so in the future – and greater general flexibility and accuracy, the Vantage Pro 2 will be the better choice.

Please follow the links to their main product pages for more detailed information on each of the Vantage Vue and Vantage Pro 2 stations.

The main pros and cons of cabled vs wireless for the VP2 stations are shown below (the wireless technology used on the Vantage Vue stations is identical to the VP2 and hence wireless considerations are the same for both Vue and VP2). You will see that there genuinely are pros and cons to both types and one or other may be the winner in particular applications. But provided there is a reasonable chance of acceptable wireless reception, the wireless models are generally the more flexible and more convenient choice, at only a small extra cost to the cabled models.

• Sensor Options: Cabled models are limited to the standard six sensors plus the optional solar radiation and UV sensors. You should seriously consider the wireless version if you might need  further additional sensors, either now or perhaps in the future, such as additional temperature or soil moisture sensors or would like the flexibility to mount the anemometer more than a convenient cable run (42m maximum) away from the ISS;
• Wireless Reception Considerations: The wireless version is primarily intended for convenience of installation, not for transmitting data over very long distances. Predictable/reliable reception range is limited to about 250m direct line-of-sight unless one or more optional wireless repeaters is used. Each standard repeater used will give an increase in range of around 250m. (The Long-range Repeater versions do allow reception over 1km or more when fitted with appropriate antennas but are a significant extra cost and line-of-sight is still needed.) Solid walls and other substantial obstructions that intervene in the signal path between ISS and console may cause a substantial reduction in reliable range. The only material that will block the wireless signal completely is sheet metal such as metal cladding (or similar such as reinforced concrete)- the direct straight-line signal path cannot be planned to pass through such a metallic barrier. Please see our separate page that deals with wireless pros and cons for a more detailed discussion.
• Cable Run: Cabled stations require running one single thin ribbon cable between ISS (the main outside sensor unit) and the VP2 console. (The supplied cable length is 30m, with a maximum run length of up to 300m permitted – but that’s a lot of cable and a significant expense in its own right for very long runs.) For extended runs of cable outdoors, in many cases the cable may need to be buried in a simple conduit, or otherwise protected;
• Multiple displays: Secondary console displays (ie other than displays on a PC monitor) can only easily be set up for wireless stations. The sensor wireless transmitters simply broadcast their signals and any number of console receivers within range will be able to pick up the weather readings. A Vantage Vue console can be useful as a lower-cost secondary display for a wireless VP2 system;
• Electrical Isolation: The wireless stations obviously have no physical cable connection between outside and inside and therefore offer no path through which electrical surges from a nearby lightning strike could reach the station console (and any computing equipment that may be connected to the console ). For the same reason, the wireless models are also immune from any rare but possible electrical interference problems such as ground loop effects.
• Data Integrity: Wireless stations may very occasionally experience short periods of poor reception for a variety of reasons, such as very heavy rain or transient interference. While this may not necessarily affect the logging of data, applications that require the optimum continuity of data, perhaps for legal or official reasons, might be better served by the cabled version;

Are the stations difficult to set up?

The stations require no specialist knowledge to set up. All Davis systems come complete with everything needed to set up the basic weather station, including comprehensive instructions plus fixings to attach the sensors to a suitable existing mast or post. Fixing the external sensors therefore needs only very basic DIY skills. For best performance, the anemometer should be installed at higher level such as on a TV mast, which may require using a specialist such as a TV aerial installer.

How are the sensors fixed?

All Davis stations are supplied complete with fixings (eg U-bolts and screws) to attach the sensors to a suitable mast, post or other support. On the standard VP2 systems, there are only two main sensor assemblies to install: ISS and anemometer. Each of these may be fixed to a mast (32-44mm diameter) using the U-bolts supplied or to a 4″ square wooden fence post or other flat surface with substantial 3″ screws also supplied.

Where should the sensors be sited?

Recommendations for sensor siting will be found in the Advice area.

How can the console be mounted?

The VP2 console has an integral hinged support arm and will be self-standing on any flat surface. Alternatively, the console can be wall mounted. Similarly, both Vue and Wizard consoles may be table/desk or wall mounted.

Can I detach the solar/UV sensors and rain gauge from the VP2 ISS?

The solar and UV sensors are designed to be mounted in the special mounting shelf that attaches to the VP2 ISS. With the use of standard Davis extension cables it is possible in principle to separate both sensors from the ISS, but the user would need to make for themselves a new mounting shelf or bracket to hold the sensors firmly in a horizontal plane in their new location. Note that long solar and UV sensor cables will introduce a finite level of error into the readings from these sensors.

How does solar radiation intensity relate to sunshine hours?

The Davis solar sensor technically measures global solar irradiation, which is the intensity of sunshine – zero when dark, moderate values when overcast and high values under conditions of bright sunshine and, overall, weaker in winter than summer. This is the unambiguous scientific measure of the sun’s power at any given time. In contrast, ‘hours of sunshine’ as traditionally measure by a Campbell Stokes sunshine recorder is a more vague and subjective measure. It is possible in principle to convert solar radiation to sunshine hours by setting a threshold value, above which the sunshine level is deemed to be bright; this conversion is performed by the Weatherlink software but the result can only be regarded as an approximation. We are awaiting software versions that may be able to perform this conversion more accurately.

Is Weatherlink essential to link to a PC?

Yes, the Weatherlink package is essential to link any Davis station to a PC because it (a) converts the proprietary raw data output of the console into a standard serial format for interfacing to the PC and (b) acts as a data buffer to store up to several weeks worth of data when the PC may be switched off. The Weatherlink data logger is only available within the package and cannot be bought separately (ie without software).

Can I use an alternative power supply for the console?

Vue and VP2 consoles can be run for extended periods on their internal batteries, even when fitted with data loggers . (NB The 6555 WeatherlinkIP logger is an exception to this because it consumes much more power than other logger models.) The wireless consoles give the longest life on battery power alone (up to 9 months) because the batteries are not also powering the sensors, as is the case with the cabled VP2 models.

Solar power in conjunction with a suitable back‑up battery is also an option; exact specification and cost will vary with detailed requirements.