Very good antenna, made in Denmark, that covers both LW and MW. It is broadband, so there is no need to tune. It appears to be equivalent to random wire up to 20m or 30m long. Rotating this round plate you aim to the direction you wish to receive. Directivity is its main advantage. Better performance during day time in MW, excellent in LW at night. A drawback is the need for 220 V, unless you connect a 24 V battery, a bit inconvenient. Still superb after more then 20 years of use.
Some photos of the interior, amplifier and two ferrites:
Although designed for a hi-fi system, it is a dx tool.
Listening to Thessaloniki Radio "ΠΟΛΙΤΙΣΜΟΣ", on 1179 KHz, during summer in Nea Makri, Attiki, at mid day. Roadstar should be parallel to the diameter of the B & O antenna, but not necessary for that signal strength.