[Lowfer] New vertical Y antenna

[rick kirby]

Bill,
 Wow you work fast! Thats a lot of wire to put up in that short time. I 
cant wait to see the results. I think I still have a capture or 2 from  last 
season  and my receive setup hasnt changed.
 Of course once you perfect the new antenna , I will bombard you with 
questions. Not that Im giving up the loop anytime soon.Its working too well 
for me right now.
BTW; thanks for the "Y" formula..

              Rick





----- Original Message ----- 
From: "Bill Ashlock" <ashlockw at hotmail.com>
To: <lowfer at mailman.qth.net>
Sent: Wednesday, December 14, 2011 1:36 AM
Subject: [Lowfer] New vertical Y antenna


>
> 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 th
> e fringe field off to the side. It's a bit lengthy but if anyone is 
> interested, I'll post it.
>
> Bill
>
>
>
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