Thanks Paul for the long explanation!

I don't found a good source how ferrite rods works for transmitters. All say
it cannot work because of big power eating in the ferrite. How much power is
possible?
I think 1 watt should be possible.
I google on...

http://www.ancom.no/
products? They claim their ferrite rod styled antenna works as good
transmitter. See their patent application.

These seem to be near field devices even at MF, where they seem to
operate.
No! They are far-field devices.

I even saw a explosion picture of a mobile phone antenna 900MHz helix
construction as composite in a (ferrite?) filled outline.

Does an antenna exists, which receives BOTH field-vectors? If the antenna
covers only one /E or M), half of the transmitting power is lost - correct?

- Henry