Telamon wrote:
In article , Bill
wrote:


Telamon wrote:



For average earth conductivity and a 22 gauge wire the height above
ground for 500 ohms impedance would be less than 5 foot and most likely
you would want it around 2 to 3 feet off the ground.


At what frequency did you calculate this?
-Bill


The impedance of the wire is not dependent on frequency.

Z= 138 * log (4* height / wire diameter)

Don't confuse a physical property of the wire with reactance.

Well, you're correct, but. There's more to the antenna than the natural
impedance of the wire alone. You have to look at the 'feedpoint'
impedance which is totally different and thats where you'll find the
reactance which cannot be ignored in actual practice.
Z=R+jX
Thats where frequency gets into the picture and gives you a number to
work with when matching the antenna to your radio.
This is Smith Chart 101...(which I never did too well with)


-Bill