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The W8IO Antenna Site

VHF-UHF Long Boom, High Performance Antenna Designs by W8IO

(links updated 12 Aug 2017)


This page documents the various long boom VHF-UHF antenna designs that I have created. Some are entirely new designs and others are optimized versions of popular Ham designs. The entirely new antenna designs are called Loggi's. More information on the Loggi design can be found here. The optimized designs are typically popular VHF long Yagi designs that I have peaked for F/R greater than 30 dB in both the E and H planes. If possible to achieve in the same design, I will also try to improve the first sidelobe levels in both planes. Usually, these optimizations are associated with a slight decrease in forward gain (less than 0.1 dB).


Narrow Band Optimized LPDA Designs (Loggi)
Model Directive Gain (dBi) G/T E-F/R (dB) H-F/R (dB) Boom Length (feet) Boom Length (m) NEC file EZNEC file Az Pattern Elev Pattern
Loggi-144-27A116.05-1.4738.2732.6825.857.88144-27A1---
Loggi-144-27A5 16.19 -1.29 34.98 34.03 25.85 7.88 144-27A5 - - -
W8IO-LP144-22 14.3 - 35 35 22 - LP144-22 LP144-22 LP144-22-az LP144-22-el
W8IO-LP144-35-MAXFB 16.34 - 48 37 32 9.7 LP144-35MAXFB LP144-35MAXFB LP144-35-MFB-az LP144-35-MFB-el
-
-
- -
- -
-
-
-
- - - - - - -
- - -

The experimental designs shown above have not yet been built or tested.

The LP144-22 is a narrow band LPDA that covers 144-148 MHz under 1.5 VSWR.  It produces 14.1 - 14.3 dBi across the band with better than 30 dB F/R also from 144-148 MHz. Peak F/R is 35 dB near 144.2 MHz. Sidelobes are also less than 30 dB.

The LP144-35-MAXFB is also a narrow band LPDA that covers 144-148 under 1.5 VSWR.  It produces 16.34 dBi at 144.1 and gradually less gain at higher frequencies. The main feature of this design is the 47.7 dB F/R
and 73 dB F/B at 144.1 MHz. F/R is better than 40 dB from 144-144.6 MHz. Sidelobes are also less than -28 dB.



W8IO 50 MHz long boom Yagi and LPDA data (16-45 foot booms)

Model Directive Gain (dBi) +/- Gain
(DL6WU
equation)
E-F/R (dB) H-F/R (dB) E-SLL
(dB)
H-SLL
(dB)
Boom Length (feet) Boom Length (m) Boom
Length
(lambda)
NEC file EZNEC file Az Pattern Elev Pattern
Loggi-50-711.09+0.4225.720.35none-20.1164.810.8Loggi-50-7---
Loggi-50-811.69+0.5423.2723.27-30-16.6185.530.92Loggi-50-8---
LP50-9FB 11.77 -0.4634.38 28.23 none-24.624.8 7.57 1.27- - - -
Loggi-50-9
12.25+.013122.7-31.5-19.924.9
7.61.28Loggi-50-9---

The antennas shown in red are experimental and have not yet been built or tested. F/R includes all backlobes.

The DL6WU gain curve can be written as GAIN (dBi) = 7.773 * LOG (Length / Lambda) + 11.43


W8IO 144 MHz long boom Yagi data (20-42 foot booms)

Model Directive Gain
(dBi)
4 bay
G/T (dB)
+/- Gain
(DL6WU
equation)
YagiCAD
G/T (dB)
E-F/R (dB) H-F/R (dB) E-SLL
(dB)
H-SLL
(dB)
Boom Length (feet) Boom Length (m) Boom
Length
(lambda)
NEC file EZNEC file Az Pattern Elev Pattern
W8IO-144-12V15.63-+0.20-33.1527.54--17.022.36.83.27144-12V---
W8IO-144-13V16.01-+0.18-34.6828.85-21-17.325.17.653.68144-13V---
W8IO-144-14V* 16.27 -1.18* +0.18 - 34.06 30.04 -21.2 -17.7 27.16 8.28 4.0 144-14V 144-14V 144-14V-az 144-14V-el
W8IO-144-14V2 16.27 - +0.18 - 35 31 -21.1 -17.6 27.16 8.28 4.0 - - - -
W8IO-144-15V 16.58 -0.80** +0.15 - 34.33 31.53 -20.7 -17.5 30.0 9.14 4.4 144-15V 144-15V 144-15V-az 144-15V-el
W8IO-144-15FD 16.81 -0.57** +0.14 - 32.33 27.11 -23.2 -20.5 32.3 9.85 4.73 144-15FD 144-15FD 144-15FD-az 144-15FD-el
W8IO-144-16V 16.87 -0.55** +0.20 - 35.8 32.3 -19.6 -16.8 32.3 9.86 4.73 144-16V 144-16V 144-16V-az 144-16V-el
W8IO-UR5EAZ-16V* 16.94 -0.45*** +0.27 - 36.15 32.18 -19.2 -16.4 32.3 9.85 4.73 W8IO-UR5EAZ-16V 144-16V - -
W8IO-144-17V 17.11 -0.27*** +0.18 - 35.48 32.34 -19.2 -16.5 34.8 10.6 5.1 144-17V 144-17V 144-17V-az 144-17V-el
W8IO-144-18V 17.29 -0.09*** - - 35.54 32.69 -18.7 -16.2 37 11.3 5.43 144-18V 144-18V 144-18V-az 144-18V-el
W8IO-144-18V2 17.42 -0.07*** +0.28 - 34.08 30.07 -17.9 -15.5 37 11.3 5.43 144-18V2 144-18V2 144-18V2-az 144-18V2-el
W8IO-144-19V 17.62 +0.17*** +0.234 - 34.81 32.37 -17.9 -15.6 39.9 12.15 5.84 144-19V 144-19V 144-19V-az 144-19V-el
W8IO-144-20V 17.87 +0.36*** +0.28 - 37.04 31.63 -17.7 -15.6 42 12.9 6.2 144-20V 144-20V 144-20V-az 144-20V-el

The antennas shown in red are experimental and have not yet been built or tested. These are all optimized versions of popular Ham designs. The antennas shown with * have complete instructions for building. Models ending in "V" have a "V" shaped driven element. Models ending in "U" have a "U" shaped reflector.  Models ending in "FD" have a horizontal folded dipole as the driven element. F/R includes all backlobes. For the YagiCAD G/T, Tsky=200 and Tearth = 1000.

# These G/T values are calculated based on stacking distances of  4.2m (E-plane) and 4.0m (H-plane).

* These G/T values are calculated based on stacking distances of  4.4m (E-plane) and 4.2m (H-plane).

** These G/T values are calculated based on stacking distances of  4.6m (E-plane) and 4.4m (H-plane).

*** These G/T values are calculated based on stacking distances of 4.8m (E-plane) and 4.6m (H-plane).

The DL6WU gain curve can be written as GAIN (dBi) = 7.773 * LOG (Length / Lambda) + 11.43

Another good gain curve for yagis is given by Tom Ring, WA2PHW/K0TAR: Gain (dBd) = 10 * LOG (5.4075 * (Length/Lambda) + 4.25)


W8IO 222 MHz long boom Yagi data (19-35 foot booms)

Model Directive
Gain (dBi)
4 bay
G/T (dB)
+/- Gain
(DL6WU
equation)
YagiCAD
G/T (dB)
E-F/R (dB) H-F/R (dB) E-SLL
(dB)
H-SLL
(dB)
Boom
Length (feet)
Boom
Length (m)
Boom
Length
(Lambda)
NEC file EZNEC file YagiCAD file Az Pattern Elev Pattern
W8IO-222-15V 16.61 +3.23** +0.18 - 34.39 31.3 -20.6 -17.6 19.5 5.9 4.4 W8IO-222-15V W8IO-222-15V W8IO-222-15V W8IO-222-15V-az W8IO-222-15V-el
W8IO-222-16V 16.9 +3.53** +0.22 - 35.71 31.48 -19.6 -16.9 21 6.4 4.74 W8IO-222-16V W8IO-222-16V W8IO-222-16V W8IO-222-16V-az W8IO-222-16V-el
W8IO-222-17V 17.15 +3.84** +0.22 - 34.77 31.76 -19.1 -16.9 22.56 6.88 5.1 W8IO-222-17V W8IO-222-17V W8IO-222-17V W8IO-222-17V-az W8IO-222-17V-el
W8IO-222-18V 17.33 +4.13*** +0.19 - 35.54 32.69 -18.6 -16.3 24 7.33 5.43 W8IO-222-18V W8IO-222-18V W8IO-222-18V W8IO-222-18V-az W8IO-222-18V-el
W8IO-222-19V 17.58 +4.41*** +0.20 - 37.76 36.28 -18.0 -15.8 25.87 7.887 5.84 W8IO-222-19V W8IO-222-19V W8IO-222-19V W8IO-222-19V-az W8IO-222-19V-el
W8IO-222-20V17.90-+0.31-35.5531.09-17.6-15.727.468.376.2W8IO-222-20VW8IO-222-20VW8IO-222-20VW8IO-222-20VazW8IO-222-20Vel
W8IO-222-17 17.94 - +0.53 -1.82 24.8 24.8 -21.3 -19.5 26 7.932 5.875 W8IO-222-17 W8IO-222-17 W8IO-222-17 W8IO-222-17az W8IO-222-17el
W8IO-222-18 18.14 +4.60### +0.53 -1.71 30.9 28.7 -20.1 -18.4 27.6 8.43 6.24 W8IO-222-18 W8IO-222-18 W8IO-222-18 W8IO-222-18-az W8IO-222-18-el
W8IO-222-19 18.12 +4.82###
+0.24 -1.37 29.05 28.42 -21.4 -19.7 30 9.1 6.76 W8IO-222-19 W8IO-222-19 W8IO-222-19 W8IO-222-19az W8IO-222-19el

The antennas shown in red are experimental and have not yet been built or tested. F/R includes all backlobes. For the G/T, Tsky=70 and Tearth = 600.

** These G/T values are calculated based on stacking distances of 3.4m (E-plane) and 3.3m (H-plane).

*** These G/T values are calculated based on stacking distances of 3.5m (E-plane) and 3.4m (H-plane).

### These G/T values are calculated based on stacking distances of 3.6m (E-plane) and 3.5m (H-plane).

The DL6WU gain curve can be written as GAIN (dBi) = 7.773 * LOG (Length / Lambda) + 11.43


W8IO 432 MHz long boom Yagi data (14-32 foot booms)

Model Directive Gain (dBi)
4 bay
G/T (dB)
Stacking
Distance
for G/T
+/- Gain
(DL6WU
equation)
YagiCAD
G/T (dB)
E-F/R (dB) H-F/R (dB) E-SLL
(dB)
H-SLL
(dB)
E-BW
(deg)
H-BW
(deg)
Boom Length (feet) Boom Length (m) Boom
Length
(Lambda)
NEC file EZNEC file YagiCAD
File
Az Pattern Elev Pattern
W8IO-432-20V 17.98 9.18 1.85m+0.28 - 33.4 30.4 -16.5 -14.6 14.1 4.3 6.2 W8IO-432-20V W8IO-432-20V - W8IO-432-20V W8IO-432-20V
W8IO-432-28 19.69 - 2m+0.23 4.89 32.7 30.8 -23 -22 24.6 7.5 10.8 W8IO-432-28 W8IO-432-28 W8IO-432-28 W8IO-432-28az W8IO-432-28el
W8IO-432-2919.7910.792.3m+0.2045.033.5531.55-23.6-22.525.67.811.2W8IO-432-29W8IO-432-29W8IO-432-29W8IO-432-29W8IO-432-29
Hy-Gain 7031DX 19.74 10.29 2.4m+0.398 4.35 27.6 27.0 -19.5 -18.4 23.72 7.23 10.42 7031DX 7031DX 7031DX 7031DX-az 7031DX-el
W8IO-432-31* 19.84 10.61 2.5m+0.498 4.66 28.46 27.78 -19.3 -18.4 20.52123.72 7.23 10.42 W8IO-432-31 W8IO-432-31 W8IO-432-31 W8IO-432-31az W8IO-432-31el
W8IO-432-32*20.0310.492.3m+0.55230.8427.99-18.3-17.3202024.697.52510.85W8IO-432-32
W8IO-432-33* 20.10 10.95 2.3m+0.519 5.12 28.01 27.96 -18.8 -17.9 2020.525.54 7.78 11.22 W8IO-432-33 W8IO-432-33 W8IO-432-33 W8IO-432-33 W8IO-432-33
W8IO-432-35*20.3711.152.4m+0.5435.3331.3128.32-18.6-17.619.219.627.378.3412.03W8IO-432-35
W8IO-432-37*20.6411.422.4m+0.5965.630.5528.95-18.2-17.218.819.229.28.912.83W8IO-432-37
W8IO-432-40*21.0411.782.4m+0.6925.9633.029.09-17.2-16.417.818.032.09.7414.04W8IO-432-40

The antennas shown in red are experimental and have not yet been built or tested.  *The 432-31, 432-32, 432-33, 432-35, 432-37 and 432-40 are optimized versions of the Hy-Gain UB-7031DX beam. F/R includes all backlobes. For the YagiCAD G/T, Tsky=20 and Tearth = 350.

The DL6WU gain curve can be written as GAIN (dBi) = 7.773 * LOG (Length / Lambda) + 11.43



VHF-UHF Misc Antenna Links


Element Length Correction due to Boom

The VHF/UHF antenna NEC files shown above include the "raw" element lengths.  That is, the element lengths are those used with a wood or plastic (dielectric) boom or supported above or below a metal boom with an large insulator. To convert these raw lengths into actual lengths used when passed through the center of metal booms, you need to add a correction factor, based on whether the element is insulated and passes through the center of a metal boom, or is shorted directly to the metal boom with a clamp. If the element is insulated when it passes through the metal boom, the correction factor is approximately 15% the diameter of the boom. For example, for a 36" (raw length) insulated element passed through the center of a 1" metal boom, the YU7EF correction factor is 0.15", so the actual length should be 36.15" when built.  The table below gives correction factors for common US boom diameters.

144 MHz
Boom Diameter (inches) DL6WU/G3SEK insulated element THRU
metal boom correction factor (inches)
YU7EF insulated element THRU metal
boom correction factor (inches)
YU7EF insulated element ABOVE metal
boom correction factor (inches)
0.875 0.106 0.125 0.031
1.000 0.137 0.150 0.0375
1.125 0.170 0.188 0.047
1.250 0.206 0.215 0.0538
1.375 0.246 0.255 0.0638
1.500 0.289 0.295 0.0738
1.625 0.333 0.340 0.085
1.750 0.380 0.385 0.096

Various antenna experimentors have similar correction factors, as shown below.

Here is a link to YU7EF's Boom Correction Notes.

Here is a link to YU1AW's Boom Correction article.

Here is information from the VHF/UHF Long Yagi Workshop.

Here is a link to DG7YBN's Boom Correction Notes and his Practical Yagi Building page.

Here is a link to SM5BSZ's collection of Boom Correction information.

The plastic element insulators and stainless steel keepers may be purchased from Directive Systems here in the US.

Here are some ideas and hints to help with your home antenna construction.


Comments and corrections/additions are welcome!

contact Roger: email to 

rgcox2 (at) gmail.com

Roger Cox W8IO - Spring Lake, MI