Topband: Vertical and horizontal polarized antennas in the same space (was Propagation improves from VK6 into Europe)

n4is at n4is at
Sat Nov 17 07:38:46 EST 2018

Hi Steve.

You are 100 % right, the V works like a top hat for a vertical TX antenna.

I it simple to detune any vertical TX antenna. Vertical TX antenna is the only way to work DX on topband!

You may ask about the inverted V or low dipole, they are not 100% horizontal, actually they are 50% horizontal on the broadside and 50% vertical along the wire.

Ground reflects horizontal signals -1, it means 180 degree out of phase, and the reflected signal cancels the arriving signal, The Arriving signal is maximum only near 1 1/2 wave high above ground 750ft!!!.

The vertical reflected signal has +1 and add to the arriving signal producing gain, ground gain.

Detuning a TX antenna is like a LC circuit, you need high impedance between the antenna and the ground. The UNIPOLE or cage antenna works very well to detune grounded towers up to 30 db, and it is easy to feed with 200 ohms, becoming a very large broadband antenna. Isolated towers or inverted V is the same, they need high isolation from ground. 

I sed the same configuration for over 20 years, the open line works very well 80 - 10m.


More information about the Topband mailing list