[Elecraft] KAT100 question

[k6se@juno.com]

Vic, K2VCO wrote:

"Remember, I'm trying to get this to work on 80 and 160 meters.  Wouldn't
a 75' wire have a very low radiation resistance and high capacitive
reactance on 160?"
==========
Yes, it would.  Assuming the wire is vertical and has a lossless
(perfect) ground radial system, the impedance at the base would be about
9 ohms resistive with a capacitive reactance of about 450 ohms (at 1.830
MHz).

If the same 75' wire went from the ground up at a 45-degree angle (over
the same perfect ground system), the resistance would be about 5 ohms and
the capacitive reactance would be about 465 ohms.

Wayne or Eric should be able to answer whether the KAT100 can handle that
impedance on 160m.

For the 75' vertical wire on 80 meters (3.550 MHz) over the same good
ground system, the feedpoint impedance would be about 52 ohms resistive
with about 100 ohms of inductive reactance which could easily be tuned
out with a series capacitor, leaving you with a very low SWR on 50-ohm
coax and no need to use the KAT100 on that band.

The same 80 meter wire at a 45-degree angle (over the same ground system)
would have a feedpoint resistance of about 30 ohms and an inductive
reactance of about 89 ohms.

73, de Earl, K6SE