Ferrite, as a compound material, is fragile and easily broken, so my asumptive idea would take great care if it is tried.
Start with a ferrite rod 3-meters in length mounted vertically using a firm method of support.
At its base, wound in the style of a mammoth loopstick, a coil for direct induction of the RF output from a Part 15 transmitter into the ferrite stick.
It has been reported in these forums that using ferrite for transmission is usually impractical because the RF injection causes heating of the ferrite, but at less than 100mW this may be negligible.
Now, if my day-dream fantasy pans out, you have a 3-meter antenna that will act like a much longer antenna.
The ALPB knows.
You can try a loop antenne in combination with a ferrite rod .............
Something like this http://www.radioharrastajat.com/tekniikka/loop.html
Rob V.
Carl: I like the way you think. So far you were the only one that could receive my skywave signal.