[Antennas] Radial Formula

Fri Oct 3 14:04:55 EDT 2008

Per the 17th Edition of The ARRL Antenna Book radial length varies with the
number of radials. The higher the number of radials, the longer they need
to be for optimum performance. Also, the impedance lowers as the number of
radials increase.
Per Table 3, page 3-13
	16 radials are indicated to be .1 wavelengths long and yield a feed
point impedance of 52 Ohms with 3 db loss. Total length of wire in
wavelengths, 1.6.
	120 radials are indicated to be .4 wavelength long and yield a feed
point impedance of 35 Ohms with 0 db loss. Total length of wire in
wavelengths, 48.
This information is also available in the December 1976 QST Magazine.
That doesn't answer directly answer your questions, but is perhaps
significant in your situation.
Regards,
Dick - KA5KKT
-----Original Message-----
From: antennas-bounces at mailman.qth.net
[mailto:antennas-bounces at mailman.qth.net] On Behalf Of Deon Erwin ZS1ZL
Sent: Friday, October 03, 2008 1:30 PM
To: Reflector Antennas Qth.net
Subject: [Antennas] Radial Formula
I have two questions about calculating the length of radials.
* Which formula is used for calculating the length of 1/4 wave elevated
radials: 300/f or 246/f ?
* Which formula is used for calculating the length of 1/4 wave ground
mounted radials (laid on the ground): 300/f or 246/f ?
Deon ZS1ZL
______________________________________________________________
Antennas mailing list
Home: http://mailman.qth.net/mailman/listinfo/antennas
Help: http://mailman.qth.net/mmfaq.html
Post: mailto:Antennas at mailman.qth.net