[Antennas] 468/Freq in Mhz

[Alex Eban]

No, it's not like this: the ratio of the physical dimensions of the element
determines the magnitude of the deviation between the wavelength and the
actual length needed to resonate the element at a given frequency.
The bandwidth issue is much more complicated to analyze, since it involves
phasor analysis around the circumference of the element. Suffice to say that
up to a ratio of length to diameter of 5 the effect exists and it widens the
band quite a lot. But you wouldn't build a 80 meters vertical from a barrel
sized pipe to cover all the band!
Alex	4Z5KS


-----Original Message-----
From: TL_IARC [mailto:4z4tl at iarc.org] 
Sent: Monday, August 24, 2009 12:08 PM
To: antennas at mailman.qth.net
Cc: Alex Eban
Subject: Re: [Antennas] 468/Freq in Mhz

Actually it's the ratio of wire diameter to wavelength and not to "wire 
length".
Of course for the same freq, a wider element (wire) has more bandwidth.
And there is a limit to that to.

At higher frequencies, a thin wire is "poorer" than a thick wire (tube for 
instance due to skin
effect - which now is related quite a bit to performance.
Isaac, 4Z4TL

----- Original Message ----- 
From: "Alex Eban" <alexeban at gmail.com>
To: "'Chris Boone'" <Cboone at earthlink.net>; "'rbethman'" 
<rbethman at comcast.net>; <antennas at mailman.qth.net>
Cc: "'Jerry'" <n6vg at lanset.com>
Sent: 24 8 2009 11:18AM
Subject: Re: [Antennas] 468/Freq in Mhz


> NO!
> The ratio of conductor diameter to the element length is important: it
> influences the bandwidth of the antenna. Also, for fat elements, the 
> antenna
> is shorter.
> In the older antenna handbooks there were tables indication the percent
> shortening required, relative to the length/diameter ratio.
> Alex 4Z5KS
>
>