[GreenKeys] Coax type for simple vertical

[Richard Knoppow]

    I have to look at my text books again but by memory the feed point 
impedance of a quarter-wave vertical also depends on the thickness of 
the radiator. A conical vertical with a large angle can have 
significantly higher resistance than a plain vertical wire or thin tube. 
Also, the angle of the radials is important. By tilting the radials 
downward the reactive part of the feed point impedance can be reduced.
    I will look in the morning to see if I can find a proper reference.

On 10/13/2017 8:19 PM, Bob kb8tq wrote:
> Hi
> 
> The impedance of a quarter wave vertical over a perfect zero resistance 
> / infinite extent ground is
> half the 75 ohms of a dipole far from ground. Whatever ground resistance 
> you have adds to the 37 ohms.
> It is *rare* to get below 10 ohms for the ground side of the antenna…..
> 
> If you have a vertical that is something other than N x 1/4 wave, you 
> will need a matching network to
> take out the reactance. The design of that network will impact the 
> impedance presented to the feed line.
> It could be quite low, quite high, or 50 ohms ….
> 
> Bob
> 
>> On Oct 13, 2017, at 10:59 PM, Ralph Irish <w8roi at wowway.com 
>
-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL