A very interesting thread with much input from knowledgeable folks.
I believe much of the commentary in the ARRL Antenna Book comes from
research done by Jerry Sevick, W2FMI in the late 60s and early 70s and
originally appearing in a series of articles in QST magazine. Sevick
undertook a massive project that gathered data from many different radial
layouts and lengths, including radial, rectangular, and with the wires in
those configurations connected together laterally in different grid fashions
or left independent of each other. Much of his research was centered on
short verticals (less than 1/4 wave) where the low input impedance makes
ground losses very important to overall system efficiency, as pointed out by
Steve, G3TXQ in this thread. His conclusion that a 120-radial system is
optimum, to my knowledge, has not been factually disputed.
73, Sam AE5L
----- Original Message -----
From: "Larry Banks" <firstname.lastname@example.org>
To: "K2VI" <email@example.com>
Sent: Thursday, January 13, 2011 5:19 PM
Subject: Re: [TowerTalk] ground radial project
> Hi Tony,
> This is from the ARRL Antenna Book:
> Practical Suggestions For Vertical Ground Systems
> At least 16 radials should be used if at all possible.
> Experimental measurements and calculations show that with
> this number, the loss resistance decreases the antenna efficiency
> by 30% to 50% for a 0.25 wavelength vertical, depending on
> soil characteristics. In general, a large number of radials (even
> though some or all of them must be short) is preferable to a
> few long radials for a vertical antenna mounted on the ground.
> The conductor size is relatively unimportant as mentioned
> before: #12 to #22 copper wire is suitable.
> a.. If you install only 16 radials they
> need not be very long - 0.1 lambda is sufficient.
> b.. If you have the wire, the space and the patience to lay
> down 120 radials (optimal configuration), they should
> be 0.4 lambda long. This radial system will gain about 3 dB
> over the 16-radial case.
> c.. If you install 36 radials that are 0.15 lambda long, you will
> lose 1.5 dB compared to optimal configuration.
> Hope this helps!
> 73 -- Larry -- W1DYJ
> ----- Original Message -----
> From: <firstname.lastname@example.org>
> To: "K2VI" <email@example.com>
> Cc: <firstname.lastname@example.org>
> Sent: Thursday, January 13, 2011 2:48 PM
> Subject: Re: [TowerTalk] ground radial project
>> As many radials as can be put down and as long as possible.
>> "Resonant" is not important.
>> Quoting K2VI <email@example.com>:
>>> Ok, thanks to all who responded to my last post. really appreciate
>>> all the help. I considered the ground bus system but didn't want to
>>> bury the aluminum due to it disintegrating in 5 years and above
>>> ground how could it be secured without it shifting. So i just went
>>> ahead and ordered the DX engineering stainless plate. It U bolts
>>> right to the post. I just bought 26,000 feet of # 14 stranded
>>> insulated copper wire at a govt surplus bussiness in norfolk va. I
>>> paid 615.00. I know i will never use all of it in a lifetime but who
>>> knows. For that price i had to jump on it. So the question is on my
>>> 43' vertical how many radials would you reccomend before it's a
>>> waste of time and should i make them longer than the antenna. I can
>>> run some as long as 55' and some as short as 25'. Im thinking 25'
>>> would be ineffective. Any ideas. thanks in advance.
>>> tony k2vi
>>> TowerTalk mailing list
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