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The following chart shows various calculations depending on the desired center frequency. The
frequencies shown here are various CW, DX, and SSB frequencies used in the ARRL Band Plan for
the United States:
Band
(Meters)
Typical Center
Frequency
(MHz)
Distance between antennas
(1/4-wavelength - free space)
at the Center Frequency
Meters
Feet
160
1.815
41.3
135.5
1.830
40.9
134.4
IDEAL 160 M
1.845
40.6
133.3
1.900
39.5
129.5
80/75
3.550
21.1
69.3
3.575
21.0
68.8
3.650
21.0
67.4
IDEAL 80 M
3.710
20.2
66.3
3.795
20.0
64.8
60
5.357
14.0
45.9
IDEAL 60 M
40
7.040
11.0
34.9
7.110
11.0
34.6
7.150
10.4
34.4
IDEAL 40 M
7.225
10.3
34.0
30
10.125
7.4
24.3
IDEAL 30 M
20
14.050
5.33
17.5
14.150
5.30
17.4
IDEAL 20 M
14.225
5.27
17.3
17
18.120
4.15
13.6
IDEAL 17 M
15
21.075
3.57
11.7
21.200
3.54
11.6
IDEAL 15 M
12
24.940
3.02
9.9
IDEAL 12 M
10
28.075
2.69
8.8
28.400
2.65
8.7
IDEAL 10 M
29.000
2.59
8.5
Typical Dual Phase Vertical Antenna Spacing
(Use the formula 246/Center Frequency in MHz for exact distances in feet)
