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Antenna Radials	Reply
by NB9N on June 3, 2008	Mail this to a friend!
Ihave currently homebrewed an 80/40 meter vertical antenna similiar to the butternut design. Question: Putting radials down will be a logistical dilemma due to a garden etc. So I was reading one particular article with interest as it mentioned that if you had a shortened antenna (in my case 39 feet) because of the "squashed" lobe pattern of the signal, that you would only need to run the radials as long as the antenna was physically long or 39 feet. (for the most part) Also is it possible to run some of my radials as deep as 18 inches for at least 1/4 of the radials?

RE: Antenna Radials	Reply
by WB6BYU on June 3, 2008	Mail this to a friend!
Radials on the ground don't need to be resonant. Generally speaking, the longer the better, but making them as long as the antenna is high is a reasonable tradeoff for getting much of the available gain. (Longer is good, more is good, and there is a point of diminishing returns beyond which you don't get much improvement for a lot of additional wire.) Burying the radial increases the losses. You might do better to run wires around the perimeter of your garden rather than burying them underneath it. Installing radials isn't an exact science, rather it is a continuous compromise between efficiency and time / cost / materials, tailored to the constraints of your specific physical location.

RE: Antenna Radials	Reply
by W5FYI on June 3, 2008	Mail this to a friend!
Take a look at the ARRL Antenna Book under "Optimum Ground-System Configurations. It gives a table comparing the number of radials vs. their length, and states "Using radials considerably longer than suggested for a given number or using a lot more radials than suggested for a given length, while not adverse to performance, does not yield significant improvement either." The table gives lengths of .1 wavelength for 16 radials to .4 wavelength each for 120. Loss is greater for numbers less than 120 radials, but if you can't put in that many long radials, you can certainly put in fewer and shorter ones. As to depth, you should stick to two or three inches or less.

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