Antenna comparison, Windom vs. 3-element beam

[N0LF]

I currently have an 80M-10M Windom antenna for my amateur rig with the center up about 50ft and the ends down around 25ft (inverted V, mostly because it would be painful to get the ends up to the same height as the center). I can put up a multi-band 3-element beam (a Mosley "Pro" model) on my roof, but can only get it to about 35ft.

At the heights listed, will there be a marked performance advantage gained by putting up the beam?

Thanks - Mark

 

[nanZor]

These two antennas are so different that a lot depends on your needs and operating style.

An inverted vee fed like a windom would be a pretty omnidirectional antenna I would think. I'd have to model it and include the feedline if it is part of the antenna system overall - generally a lot of rf is going everywhere.

The beam, assuming it is high enough for the lowest band you want to use will provide forward gain, and front-to-back rejection. Is that what you need? DX'ing or contest chasing? Great. Running or taking part in a wide-area network? Maybe not so great if you have to take the time to swing the beam around all the time.

I'm not familiar with the Mosley, so perhaps someone else can comment on how that performs. Just remember that forward-gain isn't everything. Generally 6db gain is equivalent to only 1 S-unit improvement, so you can generalize how much of an improvement you'd make/hear with the other end. Generally - propagation, noise, and other conditions are also a factor. Is the other end of the link using a 3-foot slinky antenna?

 

[wyomingmedic]

For chasing DX on 20 and up, it would be like turning on a light switch!!! I ran verticals and wire antennas for years. Last year, I finally was able to put up a 6 element tribander at 50 feet.

I started my DX count from scratch and was able to work over 200 new entities in 1 year, all at 100 watts.

But I still have a dipole for NVIS work locally on 40 and 80. Hard to beat a low dipole for that.

WM

 

[kb2vxa]

I think you mean 20 and down, as the frequency goes up the wavelength goes down. In any case a horizontal antenna be it some form of dipole (a Windom is one such form) or a beam it must be at least 1/2 wavelength above the ground to achieve a low vertical takeoff angle for good DX. For 20M that is about 66' so I doubt the beam would give you dynamite results but usable and the Windom may even do better, inverted V fashion is not all that directional. The only way to compare them is by flipping a coaxial switch back and forth for a practical A-B comparison. Things vary greatly with frequency, distance and propagation conditions so use whichever antenna gives you the best results at the time of the contact.

 

[wyomingmedic]

I think you mean 20 and down,

No, actually I don't. He is looking at a Mosley tribander (20,15,10 meters). So it will give much better performance from 20 meters (14 mhz) and UP through its designed range of 15 meters (21 mhz)) and 10 meters (28 mhz).

WM

 

[N0LF]

Hi guys - thanks for your replies. Sorry for my delay getting back to you - my spam filter caught the message from "RadioReference" - that's been fixed now.

If I'm looking for a half-wave from ground, that puts the offset for the 20M elements at 10M above ground, so I think I'm in the right ballpark. I've gotten lots of anecdotal reports from hams since I've asked the question (here and in other forums) that this clearly will make a difference, so I'll do this. Wyomingmedic, your analogy about turning on a switch is about what they've reported.

I'd go higher if I could, but that's a whole new investment to get the antenna above the trees in my back yard. I have the area above the house so that's what I'm working with. I think I can find a three-element antenna model somewhere, too - if I can, I'll take a look at the effect of lossy ground around a half-wave up. Hopefully it won't show the big lobe pointed at the moon.

thanks - Mark/n0lf

 

[W2NJS]

The whole answer can be boiled down to the fact that the Windom has no no gain and the beam has at least some gain, but the Windom has a much broader pattern compared to the beam.. Many of us use beams that are NOT above the tree line; they work somewhat better with the leaves off the trees but on the whole they're still better than a wire any day.

 

[mtindor]

In any case a horizontal antenna be it some form of dipole (a Windom is one such form) or a beam it must be at least 1/2 wavelength above the ground to achieve a low vertical takeoff angle for good DX. For 20M that is about 66' ...

1/2w on 20m is 66' ? That's news to me. More like 33'.

M