Taking Cecil's example a step further. The radiation resistance [Rr] of
an 8 foot antenna at 3.9 MHz is in the range of 1 to 2 ohms depending
upon coil location. The antenna losses, I^2*R, can be in the range of 10
to 20 ohms [Ra], and the ground losses can be in the range of 10 to 20
ohms {Rg]. So, your nominal '50 ohm load' is comprised of Rr + Ra + Rg = RL.

Efficiency is (Rr/RL)*100%. So, 2/50 = 4% or 1/50 = 2%. Take your pick!

The energy is NOT reflected back. It is wasted as heat in the antenna
and ground losses!

Deacon Dave, W1MCE
+ + +

Ron wrote:

On Sat, 08 May 2004 09:12:50 -0500, Cecil Moore
wrote:


Ron wrote:

I have a Hustler amateur mobile antenna model RM-80 for 80 Meter 25-30 KHz.
Although it was designed as a mobile I want to use it as a portable, can
anybody tell me the length of the counterpoise needed for this model? or can
I just use an earth wire

Use another RM-80 as the counterpoise.

Hmmmmm, a 2% efficient antenna with a 2% efficient counterpoise. :-)



Hmmmm, I wonder what 2% efficient means. 2% radiated power with 98%
reflected back into the radio? Ability to contact only 2% of the
stations that you can receive? What?

Ron, W1WBV