It is NDB ZAG, whose coordinates can be found on Internet. Unfortunately I had forgotten to plan in advance the road to get close to it, so I asked my brother back home to send me some info via SMS. It turned out that Internet is far more detailed than any other paper map I could locate and I failed to reach the NDB location.
I had to blind shoot it while driving at 90 km/h on the high speed road going to Vrbovec. It sits North of that road. The digital SLR helped to get the antenna into the frame.
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This second picture is cropped from a 10Mpixel image and digitally zoomed 3 times.
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After these shots I tried without success to get close to the beacon site, but nothing. Village names on Internet are not written anywhere in the real world! Now I've checked through a web service with satellite pictures how to get there, so perhaps I'll try a second approach on our next trip to Zagreb.