[Lowfer] New vertical Y antenna

[Bill Ashlock]

Rick and others,

I'm all set to begin on-air testing of this new antenna once I install the loading coil and transmitter at the base and run wires to it. The capacity measurements between upper and lower "Ys" (plus fill-in wires) are complete and I'm seeing approx 400pf between them. This makes for a low Rac in the loading coil because of the relatively low inductance of 185mh at 185.3KHz.

Turned out there was quite a large-sized finge field from the top "Y" and I had to expand the lower "Y" in order to capture a good percentage of it. That rule of thumb saying the radius of the ground radials must be at least equal to the height of the antenna proved to be true, BUT I think this applies to a vertical WITHOUT top hat. When a top hat is used it appears the radius must be equal to the antenna height PLUS the radius of the top hat. At any rate it will be interesting to see how the total Rac for this antenna comes out when I apply power, but I suspect it will be very low if I have captured as much of the fringe field as capacity measurements indicate. BTW there's a formula I found for the capacity between two circular conductive planes separated by a large distance (like 50ft) that seems to work. For Lowfer antennas it comes out approx 3 times the capacity derived from the formula that is typically given in text books for closely spaced planes not accounting for the fringe field off to the side. It's a bit lengthy but if anyone is interested, I'll post it.

Bill