Hi Conor, A ferrite rod antenna should be perpendicular to the oncoming signal wavefront, and also perpendicular to its electrical field (or parallel to its magnetic field). Because you would ordinarily be close to the ground with a loopstick radio, signals will tend to be vertically polarized at the loopstick - so for most signals the ferrite rod would be horizontal, and perpendicular to the incoming signal.
If you "null" a signal by rotating the rod to point toward the signal, you may find that the best null is obtained with the rod tilted slightly upward toward the transmitter. This is because the signal wavefront tilts slightly toward the earth. Loops and loopsticks can be used to null interfering stations to hear weaker signnals on or close to the strong station's frequency. Skywave peaks and nulls are less precise than groundwave - nulls and peaks vary as skywave paths vary and fade, especially at shorter wavelengths, I think. But with groundwave, the behavior of a loopstick is fairly precise. There is something about paramagnetic materials that attracts magnetic flux and concentrates it in the material, and such magnetic material will also increases the inductance of windings around it, so the coils do not have to be as large as they would be in air. This is why ferrite loopsticks are used - a very small antenna can be effective. Ferrite is useful up to the megahertz range, and some ferrites are even useful to UHF and beyond. Bacon, WA3WDR
