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The W8IO Antenna Site - W8IO-UR5EAZ-144-16V Yagi

(updated 3 Oct 2016)

This particular antenna design was inspired by Hartmut DG7YBN and he was inspired by Gnter 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. This design was further optimized by Vladimir UR5EAZ to produce excellent gain and G/T. The E-plane achieves an amazing 36.15 dB Front/Rear (all lobes from -90 to -180 degrees) and the H-plane achieves 32.18 dB Front/Rear 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 and EU sizes- 8mm (5/16") and DE 10mm (approx 3/8").


W8IO-UR5EAZ-144-16V Performance

Electrical Performance:                     8mm Element Diameter  (approx. 5/16")         
Directive Gain (dBi)                                        16.94                                            
Power Gain (dBi)                                            16.85                                            
E-Plane F/R (dB)                                            36.15                                              
H-Plane F/R (dB)                                            32.18                                              
E-Plane 1st Sidelobe (dB)                              -19.2                                             
H-Plane 1st Sidelobe (dB)                             -16.4                                             
E-Plane Beamwidth (deg)                                28.0                                              
H-Plane Beamwidth (deg)                                29.5                                             
Max VSWR (144-146 MHz)                           1.16                                                
4 Bay G/T (dB) at 4.8m (E) x 4.6m (H)          -0.45
4 Bay G/T (dB) at 4.8m (E) x 4.8m (H)          -0.43
                                        
Interactive Excel Gain and SNR Table by Vladimir UR5EAZ (Sep 17, 2016)
Detailed Analysis by Vladimir UR5EAZ of  this antenna with rain/ice:
0.1mm  0.2mm  0.3mm  0.4mm  0.5mm
W8IO-UR5EAZ-144-16V Echo Gain
UR5EAZ Interactive Table of Echo Gain Oct 2, 2016

Mechanical Performance:
Boom Length        32.3 feet        9.85 m        4.73 wavelength

Boom Construction:

Recommended Boom diameters: 1" to 1.5" either square or round (DX Engineering or On-Line Metals)
Square Tubing:
6061-T6 square tubing (with square corners) from Online Metals
0.750" x 0.750" x 0.062" wall x 6 feet =  $6.71
1.000" x 1.000" x 0.125" wall x 6 feet = $14.17
1.250" x 1.250" x 0.125" wall x 6 feet = $21.13
1.500" x 1.500" x 0.125" wall x 6 feet = $24.79
These sections should telescope together with a little sanding/filing of the corners.

Round Tubing:
I recommend either 6061-T6 tubing or 6063-T832 tubing for strength. 6061-T6 is more expensive.
DX Engineering 6063-T832 round tubing:
     0.875" OD x 0.058" wall x 6 feet = $6.00
     1.000" OD x 0.058" wall x 6 feet = $6.30
     1.125" OD x 0.058" wall x 6 feet = $7.00
     1.250" OD x 0.058" wall x 6 feet = $8.00
     1.375" OD x 0.058" wall x 6 feet = $8.70
     1.500" OD x 0.058" wall x 6 feet = $9.50
Tubes with 0.058" walls can telescope together and can be used as wall doublers to strengthen and adapt to smaller diameters.
Heavy duty (85 mph) boom construction uses 1.5" OD sections at center tapering down to 1" OD sections at ends. (similar to M2 2M5WL)
Moderate duty (70 mph) boom construction uses 1.25" OD sections at center tapering down to 1" or 0.875" OD sections at ends.
How to drill holes in round aluminum tubing:
     Drilling of Round Hole in Round Pipe
     Drilling Holes in Pipe
     Drilling Round Stock
     Poor Mans DRO

Parasitic Element Insulators:
Recommended element insulators: G0KSC 8mm element 2 hole mount insulators 1.00 GBP each (about $1.30 each) plus shipping
Another alternative is a vibration-damping clamp. These are available with hardware and metal plates from McMaster-Carr
A cheaper/better solution is the 8mm ZSI polypropylene clamp from Global Industrial.
Here are the dimensions of the ZSI clamp cushions. Some of these are tubing sizes and some are "pipe" sizes. Pipe sizing refers to the ID not OD.
Various clamp cushions from Global Industrial: 1/4" Polypropylene, 1/4" Beta heavy, 3/8" Polypro, 3/8" Beta heavy, 1/2" Beta standard, 1/2" Beta heavy
However, if you use element sizes other than 8mm (5/16"), you will need to re-optimize the antenna.

Parasitic Element Construction:
Recommended element sources: On-Line Metals, McMaster-Carr rods , McMaster-Carr 3003 Aluminum tubing  
Elements can be either round rod or tubing (5/16" = 0.3125" or 8mm = 0.315")

Typical 5/16" Parasitic Element prices:
Online Metals - Cold finish 6061-T6 Rod - $5.65 for 6 feet (72 inches) - weight 0.09 lb per linear foot
Online Metals - Extruded 6061-T6511 Rod - $2.53 for 6 feet (72 inches)
Online Metals - Drawn 6061-T6 Tube (0.065" wall) - $19.29 for 6 feet (72 inches) - weight 0.06 lb per linear foot
McMaster Carr  - Heat Treated 6061-T6511 Rod - $12.68 for 6 feet (72 inches)
McMaster-Carr - 3003 (soft 21,000 psi) Aluminum Tube (0.280" ID) - $15.48 for 6 feet (72 inches)
Typical 8mm Parasitic Element prices:
McMaster-Carr - 6061-T6 Aluminum Rods (METRIC) - $4.88 for 6 feet (72 inches)

Boom to Mast Clamp:
     
1.5" U-Bolt clamps for the boom
     2.0" U-Bolt clamps for the mast
      DX Engineering Boom to Mast Plate

Driven Element Construction Hints:

     DG7YBN hints
DE Enclosure options:  
        Hammond RP-1020 (60 x 60 x 40 mm) Typ. $6 from Newark and Mouser
Plastic Cable Gland (for DE tubes and coax cable)
       Bud Industries NG-9514 (0.236" to 0.433" dia, black color) Typ $2.30 from Mouser and DigiKey and Newark
       Bud  Industries IPG-222135-G (0.24" to 0.47" dia, gray color) Typ $1.00 from Mouser and DigiKey and  Newark
       mounting hole diameter is 0.803" to 0.815"


Type N bulkhead cable-mount connectors:
Amphenol RF 172106 (for RG-58 and LMR195) Typ. $8.19 from Mouser and DigiKey and
Amphenol RF 172132 (for RG-400 Teflon) Typ. $7.17 from Mouser and DigiKey and
Amphenol RF 172108 (for RG-8 and RG-213) Typ. $8.38 from Mouser and DigiKey and

Model Files:

W8IO-UR5EAZ-144-16V NEC file  (8mm elements)
W8IO-UR5EAZ-144-16V EZNEC file

W8IO-UR5EAZ-144-16V US Dimensions

Element Cum Spacing
(m / in)
8mm Element Dia
Ele Half-Lengths (m)
for NEC simulation
Element Lengths
Full Lengths (in)
dielectric boom
(+0.0)
Element Lengths (in)
insulated ABOVE metal
1" dia boom*
(+0.038)
Element Lengths (in)
insulated ABOVE metal
1.125" dia boom*
(+0.047)
Element Lengths (in)
insulated ABOVE metal
1.250" dia boom*
(+0.054)
Element Lengths (in)
insulated ABOVE metal
1.375" dia boom*
(+0.064)
Element Lengths (in)
insulated ABOVE metal
1.500" dia boom*
(+0.074)
Reflector 0 0.509 40.078
40.116
40.125
40.132
40.142 40.152
Driven Element
(0.375" OD)
0.285 / 11.220 0.4927 38.796
- - - - -
D1 0.421 / 16.575 0.4805 37.834
37.872
37.881 37.888 37.898 37.908
D2 0.705 / 27.756 0.4755 37.441
37.479
37.488 37.495 37.505 37.515
D3 1.245 / 49.016 0.463 36.457
36.495
36.504 36.511 36.521 36.531
D4 1.885 / 74.212 0.4555 35.866
35.904
35.913 35.920 35.930 35.940
D5 2.625 / 103.346 0.449 35.354
35.392
35.401 35.408 35.418 35.428
D6 3.42 / 134.645 0.443 34.882
34.920
34.929 34.936 34.946 34.956
D7 4.24 / 166.929 0.437 34.409
34.447
34.456 34.463 34.473 34.483
D8 5.09 / 200.393 0.433 34.094
34.132 34.141 34.148 34.158 34.168
D9 5.94 / 233.858 0.429 33.779
33.817 33.826 33.833 33.843 33.853
D10 6.77 / 266.535 0.429 33.779
33.817 33.826 33.833 33.843 33.853
D11 7.59 / 298.818 0.428 33.701
33.739 33.748 33.755 33.765 33.775
D12 8.385 / 330.117 0.427 33.622
33.660 33.669 33.676 33.686 33.696
D13 9.155 / 360.432 0.421 33.150
33.188 33.197 33.204 33.214 33.224
D14 9.850 / 387.795 0.399 31.417
31.455 31.464 31.471 31.481 31.491

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

Driven Element details:

Wet-Weather Performance (from UR5EAZ):


4NEC2 Patterns (NEC2/MP engine):










Comments are welcome!

contact Roger: email to 

rgcox2 (at) gmail.com

Roger Cox W8IO - Spring Lake, MI