Total posts : 45366
by MRAM 1500 kHz
Excellent post. And Neil, if that’s the case, I’m gonna try it!
I’ve been reading up on the EH-Star antenna. Similar to a cross-field antenna, it’s a short, fat dipole that uses cylinders rather than wire or tubing for the radiators. The theory is a little complex and hard for old school to accept but many Hams claim fair to good results. If it works, it would be of great benefit to AM broadcast stations as it is a very low profile antenna.
A big problem they had was RF on the outside of the coax shield. The big controversy was the claim that the coax shield was actually where the antenna was radiating most of its signal. Because of that either a choke (made of several turns of the coax itself) or a ferrite bead balun is placed very close to the antenna to stop or greatly reduce the RF from radiating off the coax.
The next step was to feed the antenna in a balanced configuration rather than unbalanced. They claim that this eliminated the RF on the coax problem just as does feeding any dipole antenna using a balun.
My question: Do we know of any Part 15 systems that have tried anything similar to an EH-Star antenna? Not necessarily that antenna but perhaps a center loaded dipole that could be fed in a balanced configuration. That should pretty much eliminate the RF on the feedline if the theory works for short, fat dipoles.