they have obscure descriptive names, but Any antenna, that is Less Than Half of a Quarter Wave, is usually a poor radiator
To radiate well, any AM antenna needs to approach Resonance, so if it's Mechanically Small
you need to bring it near to Electrical resonance, by either Adding a Coil somewhere, or coiling up, or folding, part of the radiator
The worst place, to add a coil to a Mechanically Short antenna, is near the feedpoint, where the Current is the highest
giving more loss....the best place, is well up high, where the same coil, would have less loss
Mechanically Very short antennas, have high currents, Very Low Ohms, and High losses, and narrow bandwidth
The "ring" Antenna is giving basically, mainly a normal Vertically polarised wave
It's difficult to see from the King David photos, the exact configuration, ... It seems the central mast, was mainly to support
the horizontal "ring" sections, and to allow them to be hinged up !!!...to reduce the width to go thru canals apparently !!!
One Possible VHF Antenna, used a Similar layout to the King David "Ring"....In the UK, Bus companies, wanted a VHF Antenna
that could be put through a Bus Washer, without being broken off, like a Quarter wave would be
Long ago, they looked like a Large White Upside down, Plate or Pie Dish, meant for use on top of an actual bus
even now in the UK, remains of them, can still be seen, on top of Bus Stops themselves...(a very poor antenna)
It used a metal plate, to support a Ring of copper, SHUNT Fed into a VERY Short vertical pillar, down to the metal plate below
Low band Version also made 68-88 megs, But this was So Narrow Bandwidth, It had Two rings, each with an adjustable Capacitor
Only links can find are..... https://nl.wikipedia.org/wiki/Capital_Radio
https://en.wikipedia.org/wiki/Capital_Radio_(pirate)
Link showing ring Folded up (scroll right down )
https://www.offshoreradio.co.uk/list50d.htm
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