LOFAR antennas

Remember this post from 2009? Probabely not! But of course I remembered my old post as I wrote it myself ;-). Something I wanted to do for a long time is to visit and investigate this LOFAR remote site myself. I think not many people here do know about this receive station site in their village Roodeschool. With the help of google maps though it is easy to find (if you know were to look for). And so this morning I went on my bicycle to make my "tourist" sightseeing. This LOFAR RS509 site is one of many to make a array of antennas forming a radio telescope. My main interest is not what they can do with it but what the construction of the antennas is made of. I found detailed information in this PDF document.

More info about LOFAR can be found on: https://www.astron.nl/general/lofar/lofar



LBA Low Band Antenna contains a LNA Low Noise Amplifier in the top cap. Dipole arms are from 1,38m long thin insulated copperwire as far as I could observe. Resonance frequency is 52 MHz. The groundplate is made from simple concrete mesh you can also buy at he DIY.

HBA High Band Antenna are made from alu. It consists of 4x4 dual lineair polarization dipoles housed in a polystyrene structure covered by polypropylene sheets also known as agricultural plastic sheet. Of course I could not take a look under the sheet so exact construction will remain a secret to me.





I observed another antenna at top of the first server housing. It is pointed to the nearby road. I guess it is a WiFi antenna so any maintance read out can be done from the road? Not shure why it is done like this as the whole site is connected to high speed internet via a optical fibre cable.

The whole site is situated about a kilometer from my home. And although the antennas are mainly pointed upwards I would still have doubts about interference from nearby amateur radio stations like me. Although I'm not transmitting signals 24/7 on the 6m band of course.