Saturday, 29 June 2013

Lightning radar RDF back on line

After about one year of maintenance (I have rebuilt all the circuit) the lightning radar, an invention of Frank Kooiman, is back on-line.
Now will follow a period of verification of the generated output, after which will be it put on the pages of KWOS.
At the moment you can display the screens of the software on this blog, or on the site

This system was developed as a hobby alternative to the existing commercial Boltek lightning detector. The advantages of the lightning radar are the low cost (€40 and up) compared to the Boltek (€350 to €600 depending on theversion), the extreme sensitivity of the system, and the possibility of joining the group system via the internet. Where Boltek detectors can detect lightning up to a range of 500km, the LR (lightning radar) has a range of 2000 to 3000km over land and several thousand km over water (e.g. lightning in Florida, south America).
One disadvantage of the LR is that it is not a plug-and-play system and therefore requires some knowledge

of electronics and familiarity with a soldering iron. In practice, this is not really a disadvantage since it means that
you learn a lot more about the science of detecting lightning.
The software functions as a single station showing the direction and estimated distance, or connects with other LR stations via the internet to perform a localisation function, displaying the result (specific direction and distance) on a map. In addition these maps can be uploaded to your website.

The electronics consists of an amplifier which boosts and filters the signal from an antenna and passes it to the soundcard of a computer (Line-in).

The lightning strikes are received using a frame antenna set at 10 kHz. At this frequency range the lightning sends impulses over a range of several thousand kilometres. The antenna consists of a frame, around which wire is wound in multiple windings. The antenna measures the magnetic part of a wave and has the advantage that it is less sensitive to interfering electrical fields. With a single antenna, the lightning strike can be detected but the direction cannot be measured. For this reason a second identical antenna is mounted at 90 degrees to the first antenna.

The direction can be calculated from the two signals measured. It is still not possible to say for certain that
the lightning strike occurred at one direction, exactly opposite direction could also have been possible (+180 degrees). This is also due to the fact that we do not know if the lightning strike had a positive or negative charge. If you are working with a single station, a third antenna is therefore necessary to detect the charge and therefore the correct direction of the strike. A single station cannot be used to determine the exact position / distance of the strike. This can only be estimated from the strength of the signal, since not all lightning strikes have the same energy. Lightning Radar works in a group of a number of stations and can therefore calculate the correct direction and the position / distance using only 2 antennas.
Now I have in test two ferrite antennas just like the ones used for the TOA system. It's not simple to adapt them to the RDF hardware but some good result is coming :-)

You can find information about Lightning Radar on:

Use the following image to check the result from the first image.

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