Comments or suggestions for changes, are welcome.
Please send them to me at : marsport@marsport.org.uk
.
The weather station is based on a WS2310 weather station. The thermometer/hygrometer is mounted in a small Stevenson screen on the NE pacing wall of the house, about 2m above the ground. The anemometer/wind vane are mounted on a short mast attached to a chimney. The rain gauge is mounted on a flat-topped chimney ajacent to the anemometer; both are about 5m agl. A Philips TouCam Pro II is used as a webcam. From 1 May 2008, the fan-type anemometer head has been replaced with a Technoline TX-20 that uses a more usual 3-cup design. This is sensitive to lower wind speeds.
I use WeatherDisplay software, which allows the weather web pages to be automatically generated. It also allows additions to the basic instrumentation in the form of 1-wire add-ons. Currently there is a lightning flash counter and a solar sensor. The 1-wire instruments are connected to the PC via a Hobby Boards USB to 1-wire interface. The main weather data and SAM magnetometer graph are uploaded every 15 minutes. The webcam image is uploaded every 15 minutes during the daytime.
The flash counter is in two parts, the flash detector and the counter. The flash detector is a modified CIGRE design, which I found here. It uses a wire antenna and a optically-isolated interface to the counter. Unlike the usual 1-wire flash detector, it is not sensitive to either RF interference or power-line spikes. It responds to cloud-ground discharges only within 10-20km, so it usually records very few counts. A trial of the 1-wire flash-counter detector design was very disappointing, with spurious flashes counted every time any electrical appliance in the vicinity has switched on or off. It was also upset by my 50MHz amateur radio equipment.
The counter part is identical to the 1-wire flash counter system from Hobby Boards.
Solar Sensor
This is the Hobby Boards Temp/Solar kit with the solar sensor and thermometer only. It is fitted in an opal glass globe light fitting for weatherproofing and mounted close to the rain gauge on the chimney.. The goal of this is merely to provide a record of sunshine. Following failure of the photodiode, a BPX 65 has been substituted.
The Northern Lights (or Aurora) are a stunningly beautiful, and moderately rare, natural phenomena. They are ultimately driven by events on the Sun, the frequency and severity of which vary over an approximately eleven year cycle. These solar disturbances can interact with the Earth's magnetic field as part of the process which produces auroral displays. Thus monitoring small changes in the field can help to predict auroral activity. This is of interest to radio amateurs as such events are often accompanied by HF radio propagation disturbances, and enhanced VHF popagation is possible by using the aurora as a reflector.
Some good hints on predicting the probability of a visual aurora at your own location can be found at this NASA site.
The SAM magnetometer was designed by Karsten Hansky, DL3HRT and Dirk Langenbach, DG3DA and was described in DUBUS magazine issue 2/03. It can measure small changes in one or two components of the earth's field, using fluxgate sensors that are make by Speke. For more details, see the SAM website. This contains both construction information and access to real-time data from a number of stations across Europe.
The installation at Willowbank now uses three sensors, one for the vertical component (Hz), one for the E-W component (Hy) and one for the N-S component (Hx). The SAM magnetometer has been modified to accept a third sensor. The magnetometer software records changes from the midnight value, in units of nanoTesla (nT). The resulting graph is uploaded every 15 minutes. On the graph you will see a series of K values, such as K=3. This is a measure of magnetic disturbance. A knowledge of the local K value, together with your magnetic latitude, can be used to judge the likelhood of an auroral display, as the link above describes. Because the fluxgate sensors used are sensitive to temperature, they are buried some 1.7m below ground. They are about 65m from the house and 80m from the road, so the effects of (the occasional) passing traffic are negligable. Records are archived and stored, so if you are interested in the magnetic records for here for any day since December 2006, they are easily available, just contact me via the e-mail link below. The instrument has recently been modified to allow connections of a third sensor
My modifications to the SAM Magnetometer design, made to improve the performance with long cables are described here.
Comments or suggestions for changes, are welcome.
Please send them to me at : marsport@marsport.org.uk
.
