Understood, Jim. Interestingly, I just found out that the ground
conductivity in my area is probably very good, on the order of 2-4
millisiemens, which may reduce the need for a huge number of radials.
In this evening's 160 contest, I've been pleasantly surprised by how
well the antenna works. It's past time to get my receiving K9AY loop
back in service
73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at<https://reversebeacon.net>.
For spots, please use your favorite
"retail" DX cluster.
On 12/2/2022 5:51 PM, Jim Brown wrote:
On 12/2/2022 12:21 PM, Pete Smith N4ZR wrote:
I just added 5 more radials to the 13 I had originally under my
inverted L, and the R dropped from 34 to 31 ohms. Barely still worth
doing, I guess.
It all depends on the difficulty/cost of adding more. The radiation
resistance of a vertical, which represents radiated power, is a
function of the vertical height, not the total length. There's a graph
of this in my tutorial. The combination of radiation resistance and
ground loss, both in Ohms, forms a voltage divider for the transmitter
current, and power lost is 10 log of the divider ratio. If, for
example, you have 50-60 ft vertical, radiation resistance is likely to
be less than 8 ohms.
73, Jim K9YC
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