Harmonics are simply multiples of a frequency. They are useful in determining what other bands/frequencies a given antenna may work for. Values shown are in MHz.
For example, let’s say a 40m antenna is designed for 7.16 MHz. It will have a 3rd harmonic of 21.5 MHz. This is extremely close to the primary frequency required for a 15m antenna. Therefore, this 40m antenna should also work well as a 15m antenna…
| Harmonic | 160m | 80m | 60m | 40m | 30m | 20m | 17m |
|---|---|---|---|---|---|---|---|
| Primary | 1.90 | 3.76 | 5.37 | 7.16 | 10.1 | 14.2 | 18.1 |
| 2nd | 3.80 | 7.53 | 10.7 | 14.3 | 20.3 | 28.4 | 36.2 |
| 3rd | 5.70 | 11.3 | 16.1 | 21.5 | 30.4 | 42.6 | 54.4 |
| 4th | 7.60 | 15.1 | 21.5 | 28.7 | 40.5 | 56.8 | 72.5 |
| 5th | 9.50 | 18.8 | 26.8 | 35.8 | 50.6 | 70.9 | 90.6 |
| 6th | 11.4 | 22.6 | 32.2 | 43.0 | 60.8 | 85.1 | 108.7 |
| 7th | 13.3 | 26.3 | 37.6 | 50.1 | 70.9 | 99.3 | 126.8 |
| 8th | 15.2 | 30.1 | 42.9 | 57.3 | 81.0 | 113.5 | 144.9 |
| 9th | 17.1 | 33.9 | 48.3 | 64.5 | 91.1 | 127.7 | 163.1 |
| 10th | 19.0 | 37.6 | 53.7 | 71.6 | 101.3 | 141.9 | 181.2 |
| Harmonic | 15m | 12m | 11m (CB) | 10m | 6m | 2m | 70cm |
|---|---|---|---|---|---|---|---|
| Primary | 21.2 | 24.9 | 27.2 | 28.9 | 52.1 | 146 | 435 |
| 2nd | 42.5 | 49.9 | 54.4 | 57.7 | 104.1 | 292 | 870 |
| 3rd | 63.7 | 74.8 | 81.6 | 86.6 | 156.2 | 438 | 1305 |
| 4th | 85.0 | 99.8 | 108.7 | 115.4 | 208.2 | 584 | 1740 |
| 5th | 106.2 | 124.7 | 135.9 | 144.3 | 260.3 | 730 | 2175 |
| 6th | 127.4 | 149.6 | 163.1 | 173.1 | 312.3 | 876 | 2610 |
| 7th | 148.7 | 174.6 | 190.3 | 202.0 | 364.4 | 1022 | 3045 |
| 8th | 169.9 | 199.5 | 217.5 | 230.8 | 416.4 | 1168 | 3480 |
| 9th | 191.1 | 224.5 | 244.7 | 259.7 | 468.5 | 1314 | 3915 |
| 10th | 212.4 | 249.4 | 271.9 | 288.5 | 520.5 | 1460 | 4350 |
Note: All primary frequencies listed are for the middle of each band and are in MHz.
