I have a similar vertical that I built that works pretty well on top band at
P40A. Mine 54' feet of freestanding aluminum and I top load it with a wire
going back toward the ground in an inverted "L" configuration. I use a hair
pin coil at the base to bring the impedance to 50 ohms.
John KK9A
To: <towertalk@contesting.com>
Subject: Re: [TowerTalk] WTB: GAP VOYAGER and a Zero Five
From: RICHARD SOLOMON
Date: Fri, 9 May 2008 23:10:48 +0000
That takes care of my idea to put one up for 160 !!
You guys just saved me a bucket of money, guess I'll use it to fill the
tank instead.
73, Dick, W1KSZ
To: towertalk@contesting.com
Subject: Re: [TowerTalk] WTB: GAP VOYAGER and a Zero Five
From: K4SAV <
Date: Fri, 09 May 2008 17:57:17 -0500
Here is an EZNEC simulation of the gain of a Zero Five using 32, 100 ft
radials, average ground, and 100 ft of RG213, also including a 4 to 1
balun at the feedpoint as recommended by Zero Five and assuming no balun
loss. The gain numbers are all at 15 degrees elevation, regardless of
what the take-off angle is. The last number is the amount of power
dissipated in the coax assuming an input of 1500 watts.
1.8 MHz -17.5 dBi, 1292 watts
3.5 MHz -8.1 dBi, 598 watts
7 MHz -3 dBi, 226 watts
10.1 MHz -1.7 dBi, 532 watts
14 MHz -3.3 dBi, 585 watts
18.1 MHz -4.3 dBi, 306 watts
21 MHz -3.1 dBi, 448 watts
24.9 MHz -6.9 dBi, 674 watts
28 MHz -12.2 dBi, 362 watts
Here are the gain numbers for the same set-up except no 4 to 1 balun:
1.8 MHz -22.2 dBi
3.5 MHz -10 dBi
7 MHz -3.6 dBi
10.1 MHz -4.8 dBi
14 MHz -5.5 dBI
18.1 MHz -5.2 dBi
21 MHz -5.6 dBi
24.9 MHz -9.6 dBi
28 MHz -12.4 dBi
This is really comparing apples and oranges, but just for reference,
here is the gain of a half wave dipole (one on each band) at 43 feet
using 100 ft of RG213. The gain is at 15 degrees elevation regardless
of what the take-off angle is, and the gain is broadside to the dipole.
1.8 MHz -5.9 dBi
3.5 MHz -3.2 dBi
7 MHz 0.15 dBi
10.1 MHz 3.3 dBi
14 MHz 5.9 dBI
18.1 MHz 6 dBi
21 MHz 6.3 dBi
24.9 MHz 6.6 dBi
28 MHz 5.6 dBi
Jerry, K4SAV
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