I can't believe this. Just using a different browser (Firefox) to view wxforum and I've found it makes a huge improvement. Other browser does not render pictures properly. In particular many pictures are clipped on the right side.
Only now have I a proper full view of the mystery component, and I can say without hesitation that it is indeed the WWVB ferrite core antenna for the sensor head. So this coil resonates with a capacitor at 60 kHz.
Here's further confirmation. A picture of a DCF module; DCF being the German equivalent of WWVB. The same antennas are probably sold for both stations, with just a change of the resonating capacitor's value to adjust for the slightly higher freq. of DCF.
Gosh, I can't upload this little jpg of about 14 kByte size. Have no idea why and I've uploaded many pics to a forum almost identical to this one. I'll keep working on the upload and it may be due to almost running out of HD working memory on this PC, which is the reason for going to Firefox; the other browser refuses to run without more memory.
It's a solid state drive and isn't big enough. It was an experiment and I already have another twice-as-big SSD of 100 GB for this PC.