ANTENNAS FOR 100 POUND DXPEDITIONS
Over 32 radials length 8 feet
Over 32 radials length 16 feet
Over 32 radials length 33 feet
Force-12 Sigma-5 on 20m Figure 255 Varying radial length for 32 radials over a vertical dipole Computations were performed for the five bands over this new set of radials (16 by 33-feet) which yielded the following new data.
Band
No radials
With 16 radials 33 feet long
Difference
10m
-0.45 dBi
1.49 dBi
1.94 dB
12m
-0.79 dBi
0.62 dBi
1.41 dB
15m
-1.20 dBi
-0.36 dBi
1.56 dB
17m
-1.59 dBi
0.06 dBi
1.65 dB
20m
-2.29 dBi
1.08 dBi
3.37 dB
Table 6 Force-12 Sigma-5 gain comparisons 16 33-foot radials vs. no radials The numbers hint at something going on here other than a simple linear relationship between gain and radial length. The table below shows data for radial lengths 8 feet through 48 feet in roughly four-foot increments. The bands are arrayed in the vertical axis; the lengths of each of the 16 radials is shown in the horizontal axis. 206