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

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 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. 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