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Charging an electric car

Submitter: Menno Norden
Description: LOFAR is a pretty sensitive radio telescope, especially in the low band mode from 10 to 90 MHz. In the past we found RFI from LED lamps, air conditioner units, electric fence and other electronic equipment surrounding our LOFAR stations.

This time we were curious whether the charging of an electric vehicle would be noticeable. To evaluate this, the engineers from DE603 (Tautenburg) Michael Kehr and Ralf Neubert placed an electric car at an unknown position. The car borrowed from colleague Ulf Kypke-Burchardi, had an almost empty battery. During the charging of the car I recorded the crosslet statistics of the LBA for multiple subbands across the frequency band. From this data an all-sky (upper-right) and near-field (upper-left) image at 58.6 MHz was created.

The location of the car is indicated with the black circle. The RFI from the dome was mainly from a climate data converter box (lower-right). This box was disabled during the test. A smaller RFI source was still present during the recordings.

They also moved the car to a second position, but also well detected by LOFAR. After the coffee break, the car was fully charged and RFI was luckily gone! We also tried a second (hybrid) car but could not detect it.

The good news is that although LOFAR can detect this at about 100 meter distance, the level is still very low and undetectable in the all-sky image. This gives a good impression what we can expect from charging of electric vehicles.
Copyright: Astron
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