On Jan 10, 9:06*am, Dave wrote:
Richard Fry wrote:
On Dec 30 2008, 8:50 am, Eric wrote:
NEC shows this for a theoretically perfect 1/4-wave vertical
monopole system: etc

I need to correct the values I posted earlier. I mis-read the larger
table I had constructed, which was apparent when calculating the
values for a ~200 degree vertical.

Frequency = 3.9 MHz
Conductivity = 5 mS/m
Applied Power = 100 watts

Groundwave Field at 10 miles = 131 µV/m (Correction)
Groundwave Field at 20 miles = 31.7 µV/m (Correction)

Wouldn't a 200 degree vertical work better?

Yes, by a little over 2 dB (other things equal).

Groundwave Field at 10 miles = 167 µV/m
Groundwave Field at 20 miles = 41 µV/m

RF