Gain is most of what decides how much separation you need. End-fed wire is taken here at 2.15 dBi, which is typical. The table gives the distance the general public needs to be, band by band, at 100 watts.
| Band | Steady carrier | SSB voice | Near field starts |
|---|---|---|---|
| 160 meters | 0.85 ft | 0.27 ft | 82.4 ft |
| 80 meters | 1.68 ft | 0.53 ft | 41.7 ft |
| 60 meters | 2.39 ft | 0.76 ft | 29.3 ft |
| 40 meters | 3.20 ft | 1.01 ft | 21.9 ft |
| 30 meters | 4.53 ft | 1.43 ft | 15.5 ft |
| 20 meters | 6.34 ft | 2.00 ft | 11.0 ft |
| 17 meters | 8.10 ft | 2.56 ft | 8.64 ft |
| 15 meters | 9.49 ft | 3.00 ft | 7.38 ft |
| 12 meters | 11.1 ft | 3.53 ft | 6.28 ft |
| 10 meters | 12.9 ft | 4.08 ft | 5.43 ft |
| 6 meters | 13.4 ft | 4.24 ft | 3.10 ft |
| 2 meters | 13.4 ft | 4.24 ft | 1.07 ft |
| 1.25 meters | 13.4 ft | 4.24 ft | 0.70 ft |
| 70 centimeters | 11.1 ft | 3.50 ft | 0.36 ft |
All figures at 100 watts to the general public limit, ground reflection included. Where the required distance is smaller than the near-field figure in the last column, the estimate has stopped being meaningful — in plain terms, there is nothing to worry about beyond not standing at the antenna.
Work out your own station in Exposure Forge — six questions, and it prints a dated record you can keep.