W8IO Antenna Site

The W8IO Antenna Site - 144-19V Yagi

(updated 28 Sep 2015)

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 34.81 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").

144-19V Performance

Electrical Performance:                    0.250" Element Diameter            0.188" Element Diameter
Directive Gain (dBi)                                        17.62                                            xx
Power Gain (dBi)                                            17.51                                            xx
E-Plane F/R (dB)                                            34.81                                            xx
H-Plane F/R (dB)                                           32.37                                            xx
E-Plane 1st Sidelobe (dB)                            -17.9                                        xx
H-Plane 1st Sidelobe (dB)                             -15.6                                              xx
E-Plane Beamwidth (deg)                               26.0                                            xx
H-Plane Beamwidth (deg)                                27.5                                            xx
Max VSWR (144-146 MHz)                           1.5                                                xx
4 Bay G/T (dB) at 4.8m (E) x 4.6m (H) +0.17                                              xx
4 Bay G/T (dB) at 4.8m (E) x 4.8m (H) +0.22                                              xx
4 Bay G/T (dB) at 5.0m (E) x 5.0m (H) +0.31 xx

Mechanical Performance:
Boom Length        39.86 feet       12.15 m        5.838 wavelength
Recommended Boom diameters: 1" to 1.625" either square or round (Texas Towers, DX Engineering or On-Line Metals)
Recommended element insulators: Directive Systems
Recommended element sources: On-Line Metals, McMaster-Carr

144-19V NEC file EZNEC file (1/4" elements)
144-19Vse NEC file EZNEC file (3/16" elements)

144-19V Dimensions

Element	Cum Spacing (m)	0.250" Element Diameter Element Half-Lengths (m) Dielectric Boom or NEC simulation	0.188" Element Diameter Element Half-Lengths (m) Dielectric Boom or NEC simulation
Reflector	0	0.5095	0.51205
Driven Element (0.375" OD)	0.286	0.4905	0.4905
D1	0.421	0.482	0.4845
D2	0.707	0.4775	0.480
D3	1.246	0.466	0.4685
D4	1.886	0.4585	0.4610
D5	2.628	0.451	0.4535
D6	3.419	0.445	0.4475
D7	4.239	0.439	0.4415
D8	5.086	0.4345	0.437
D9	5.939	0.4315	0.434
D10	6.771	0.431	0.4335
D11	7.592	0.432	0.4345
D12	8.393	0.431	0.4335
D13	9.160	0.426	0.4285
D14	9.925	0.422	0.4245
D15	10.658	0.420	0.4225
D16	11.300	0.408	0.4105
D17	12.150	0.400	0.4025

Driven Element details (in):

4NEC2 Patterns:

Comments are welcome!

contact Roger: email to

rgcox2 (at) gmail.com

Roger Cox - Spring Lake, MI