W8IO Antenna Site

The W8IO Antenna Site - 144-16V Yagi

(updated 28 Sep 2016)

This particular antenna design was inspired by Hartmut DG7YBN and he was inspired by Günter DL6WU and Brian K6STI. His designs blend extremely high antenna gain, high G/T (which means a low noise temperature) along with a broad gain and VSWR bandwidth. The DE design is also very easy to build and allows adjustment of VSWR without significantly affecting the gain and pattern performance. A broad VSWR and gain bandwidth is ideally suited for wet and snow/ice climates where accumulation of moisture on the elements can lower the antennas resonant frequency and degrade performance. In this design, I have adjusted the spacing and element lengths slightly to increase the Front/Rear to values over 30 dB in each plane. The E-plane achieves an amazing 35.8 dB Front/Rear (all lobes from -90 to -180 degrees) at 144.1 MHz. This allows the antenna to reject terrestrial noise sources to an extremely high degree for improved EME performance in noisy locations. Element diameters are common US sizes (1/4" and 3/16").

144-16V Performance

Electrical Performance:                    0.250" Element Diameter            0.188" Element Diameter
Directive Gain (dBi)                                        16.87                                            16.77
Power Gain (dBi)                                            16.76                                            16.65
E-Plane F/R (dB)                                            35.8                                            35.91
H-Plane F/R (dB)                                            32.3                                           31.93
E-Plane 1st Sidelobe (dB)                            -19.6                                        -19.7
H-Plane 1st Sidelobe (dB)                             -16.8                                             -16.8
E-Plane Beamwidth (deg)                               28.4                                              28.4
H-Plane Beamwidth (deg)                                30.0                                            30.0
Max VSWR (144-146 MHz)                           1.5                                                1.5
4 Bay G/T (dB) at 4.6m (E) x 4.4m (H)          -0.55                                            -0.55

Mechanical Performance:
Boom Length        32.3 feet        9.86 m        4.73 wavelength
Recommended Boom diameters: 1" to 1.5" either square or round (DX Engineering or On-Line Metals)
Recommended element insulators: Directive Systems
Recommended element sources: On-Line Metals, McMaster-Carr

144-16V NEC file EZNEC file (1/4" elements)
144-16Vse NEC file EZNEC file (3/16" elements)

144-16V Dimensions

Element	Cum Spacing (m / in)	0.250" Element Diameter Element Half-Lengths (m) Dielectric Boom or NEC simulation	0.250" Ele Dia Element Full Lengths (inches) with Dielectric Boom	0.250" Ele Dia Element Full Length (in) including metal Boom Correction 1", 1.125", 1.25", 1.375", 1.5"	0.188" Element Diameter Element Half-Lengths (m) Dielectric Boom or NEC simulation
Reflector	0/0	0.5095	40.118		0.51205
Driven Element (0.375" OD)	0.286 / 11.260	0.4905	100mm = 3.937" 490.5mm = 19.311" (boom center to tip)		0.4905
D1	0.421 / 16.575	0.482	37.953		0.4845
D2	0.707 / 27.835	0.4775	37.598		0.480
D3	1.246 / 49.055	0.466	36.693		0.4685
D4	1.886 / 74.252	0.4585	36.102		0.4610
D5	2.628 / 103.464	0.451	35.512		0.4535
D6	3.419 / 134.606	0.445	35.039		0.4475
D7	4.239 / 166.889	0.439	34.567		0.4415
D8	5.086 / 200.236	0.4345	34.213		0.437
D9	5.939 / 233.818	0.4315	33.976		0.434
D10	6.771 / 266.574	0.431	33.937		0.4335
D11	7.592 / 298.897	0.4295	33.819		0.432
D12	8.388 / 330.235	0.430	33.858		0.4325
D13	9.160 / 360.629	0.423	33.307		0.4255
D14	9.860 / 388.188	0.4025	31.693		0.405

Driven Element details (in):

4NEC2 Patterns:

Comments are welcome!

contact Roger: email to

rgcox2 (at) gmail.com

Roger Cox - Spring Lake, MI