Contesting with Verticals & VDAs. Pete VE3IKV / VA3RA / VP2EAT

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1 Pete VE3IKV / VA3RA / VP2EAT

2 Verticals means both gain-type HF monoband verticals and vertical directional arrays (VDAs) Object is to keep the main vertical radiation pattern as low as possible (<10 degrees) in order to maximize F2 signal propagation & signal strengths Simple trap yagis, spiderbeams, etc. low to the ground have a much higher radiation angle, and therefore substantially less gain below 10 degrees Simple monoband VDAs can also provide additional gain, and an even lower radiation pattern when near salt water, or when elevated with a clear horizon Omnidirectional pattern (or hemispheric pattern with VDAs) may be useful during contests, since a rotor is not necessary

3 Gain Monoband Verticals What is a gain monoband vertical? When properly matched with a low-loss network at the base, and using an extended 0.64 wavelength radiating element, and four 0.67 wavelength radials sloping at 45 o, the monoband vertical will have: approximately 5dBi omnidirectional gain a low vertical radiation angle of approximately 8 degrees above the horizon a 50-ohm source impedance with low VSWR A matching network of 5/16 copper refrigeration tubing wound on a section of 4 diameter plastic septic drainage pipe makes a very low-loss matching network

4 0.64 wavelength produces the maximum gain before the radiation pattern begins fracturing into multiple lobes (2x = old extended double zepp ) The 0.64 wavelength gain vertical open-coil tapped matching network is inherently grounded, so as a result the antenna exhibits: very low noise, the VSWR is not affected by rain, and it has rejection of out-of-band signals due to the tapped matching coil design voltage maxima is at a higher physical height than a ¼ wave vertical (a 10m 0.64 wavelength radiator = 22 feet vs. 10m ¼ wave = 8.2 feet) less RFI at rig as a result

5 Monoband WL radials vertical pattern

6 10m 0.64 WL monoband gain vertical at VP2EAT

7 10m 0.64 WL monoband gain vertical at PJ7/VA3RA

8 10m 0.64 WL monoband gain vertical at FJ/VA3RA

9 Year 1: Results using a 10m monoband 0.64 lambda gain vertical: 2011 TOP CQ WW DX CW SOSB/10 LP 9J3A...1,403,506 (S53A) HP1WW...1,166,400 (OH0XX) J28RO...800,382 (F5IRO) C4Z ,150 (5B4AIZ) 5C5W...642,432 VP2EAT...508,599 (VE3IKV).notice all the 3-pointers!

10 Year 2: Results using a 10m monoband 0.64 lambda gain vertical: 2012 TOP CQ WW DX CW SOSB/10 LP C4Z...600,134 (5B4AIZ) UK9AA...481,664 VK9/OG1M...376,263 (OH1VR) HQ2N...373,524 (JA6WFM) PJ7/VA3RA...369,930 (VE3IKV) VK6AA...355,840 (VK2IA).notice all the 3-pointers!

11 Year 3: Results using a 10m monoband 0.64 lambda gain vertical: 2013 TOP CQ WW DX CW SOSB/10 LP NP3A...1,060,352 FJ/VA3RA...625,664 (VE3IKV) N8II...434,000 C6AZZ...430,000 (KQ8Z) OK1FDR...408,519 WB4TDH...344,998 still all with only a keyer & a paper log!

12 Vertical Directive Arrays (VDAs) Used by recent DXpeditions TX6G, T32C, VP6DX, FT4TA, etc. rather than low horizontal yagis (10-20m) The VDA is a 2-element ½ wave yagi in the vertical plane, with a wire dipole driven element and a wire reflector behind it Broad 139 o beamwidth in the horizontal plane Low 7 o elevation angle in the vertical plane 8dB gain relative to a low horizontal beam reported when used over sea-water wetted sand, or when used elevated over normal ground 30dB null at the rear (!)

13 Forward direction The 2-el wire VDA

14 BAND MAST BOOM LB HB LF D/2 R/2 DS RS d1 d2 20m 12.5m 4m 1.78m 6.24m 6.0m 4.77m 5.07m 0.46m 0.42m 1.62m 1.51m 17m 10m 3m 1.39m 4.87m 4.6m 3.69m 3.97m 0.37m 0.33m 1.30m 1.19m 15m 10m 3m 1.19m 4.45m 4.2m 3.18m 3.40m 0.31m 0.28m 1.09m 1.01m 12m 8m 3m 1.01m 3.91m 3.7m 2.70m 2.88m 0.26m 0.24m 0.91m 0.87m 10m 8m 3m 0.89m 3.66m 3.4m 2.39m 2.55m 0.23m 0.19m 0.81m 0.67m 2-el VDA dimensions for each HF band - 20m to 10m* * Courtesy G3WGN & G3SVL

15 The 2-el wire VDA has approx 30dB F/B ratio!

16 2-el wire VDA cardioid pattern in the horizontal plane

17 VSWR plot for 12m version of VDA

18 If you don t have a conductive salt-water ground, elevate the antenna as high as possible in order to get a clear path to the horizon, otherwise you will get reduced performance For use at the beach, the following are the min. recommended heights of the boom above ground: 20m 6.24m; 15m 4.45m; 10m 3.66m Away from the beach, raise the boom as high as you can Boom and support mast must be composite nonconducting material Coax feedline should exit the boom at the center, at a 90 o angle for at least 1 wavelength before dropping to the ground. Ferrite common-mode chokes may be necessary on the feedline.

19 20 meter elevated ground-plane vertical at CY0X

20 Thanks any questions?