Coax Cable Loss

These calculations for Pout (Power out in watts) are for an input of 50 watts.
Cables listed are typical coax cables by Belden.

For 100 ft cables:
RG-8/U, Belden 8214 RG-8X, Belden 9258
MHz dB/100 ft Pout MHz dB/100 ft Pout
50 1.2 38 50 2.1 31
100 1.7 34 100 3.1 24
200 2.6 27 200 4.5 18
400 3.9 20 400 6.6 11
700 5.6 14 700 9.1 6
RG-8/U, Belden 9913 RG-8/U, Belden 9913F
MHz dB/100 ft Pout MHz dB/100 ft Pout
50 0.9 41 50 1.1 39
100 1.3 37 100 1.5 35
200 1.8 33 200 2.0 32
400 2.7 27 400 2.9 26
700 3.6 22 700 3.9 20
RG-58/U, Belden 8240 RG-58C/U, Belden 8259
MHz dB/100 ft Pout MHz dB/100 ft Pout
50 2.5 28 50 3.7 21
100 3.8 21 100 5.4 14
200 5.6 14 200 8.1 8
400 8.4 7 400 12.4 3
700 11.7 3 700 17.7 1
RG-174/U, Belden 8216 RG-59/U, Belden 8241
MHz dB/100 ft Pout MHz dB/100 ft Pout
50 5.8 13 50 2.4 29
100 8.4 7 100 3.4 23
200 12.5 3 200 4.9 16
400 19 1 400 7.0 10
700 27 0.1 700 9.7 5
Note: RG-59 is 75-ohm cable TV coax.

For 50 ft cables:
RG-8/U, Belden 8214 RG-8X, Belden 9258
MHz dB/50 ft Pout MHz dB/50 ft Pout
50 0.6 44 50 1.1 39
100 0.9 41 100 1.6 35
200 1.3 37 200 2.3 29
400 2.0 32 400 3.3 23
700 2.8 26 700 4.6 17
RG-8/U, Belden 9913 RG-8/U, Belden 9913F
MHz dB/50 ft Pout MHz dB/50 ft Pout
50 0.5 45 50 0.6 44
100 0.7 43 100 0.8 42
200 0.9 41 200 1.0 40
400 1.4 37 400 1.5 36
700 1.8 33 700 2.0 32
RG-58/U, Belden 8240 RG-58C/U, Belden 8259
MHz dB/50 ft Pout MHz dB/50 ft Pout
50 1.3 37 50 1.9 33
100 1.9 32 100 2.7 27
200 2.8 26 200 4.1 20
400 4.2 19 400 6.2 12
700 5.9 13 700 8.9 7
RG-174/U, Belden 8216 RG-59/U, Belden 8241
MHz dB/50 ft Pout MHz dB/50 ft Pout
50 2.9 26 50 1.2 38
100 4.2 19 100 1.7 34
200 6.3 12 200 2.5 28
400 9.5 6 400 3.5 22
700 13.5 2 700 4.9 16
Note: RG-59 is 75-ohm cable TV coax.

For 25 ft cables:
RG-8/U, Belden 8214 RG-8X, Belden 9258
MHz dB/25 ft Pout MHz dB/25 ft Pout
50 0.3 47 50 0.6 44
100 0.5 45 100 0.8 42
200 0.7 43 200 1.1 38
400 1.0 40 400 1.7 34
700 1.4 36 700 2.3 29
RG-8/U, Belden 9913 RG-8/U, Belden 9913F
MHz dB/25 ft Pout MHz dB/25 ft Pout
50 0.2 47 50 0.3 47
100 0.3 46 100 0.4 46
200 0.5 45 200 0.5 45
400 0.7 43 400 0.7 42
700 0.9 41 700 1.0 40
RG-58/U, Belden 8240 RG-58C/U, Belden 8259
MHz dB/25 ft Pout MHz dB/25 ft Pout
50 0.6 43 50 0.9 40
100 1.0 40 100 1.4 37
200 1.4 36 200 2.0 31
400 2.1 31 400 3.1 24
700 2.9 25 700 4.4 18
RG-174/U, Belden 8216 RG-59/U, Belden 8241
MHz dB/25 ft Pout MHz dB/25 ft Pout
50 1.5 36 50 0.6 44
100 2.1 31 100 0.9 41
200 3.1 24 200 1.2 38
400 4.8 17 400 1.8 33
700 6.8 11 700 2.4 29
Note: RG-59 is 75-ohm cable TV coax.

Image of graph showing power loss after 100 feet of various coax cable types.

Image of graph showing power loss after 50 feet of various coax cable types.

Image of graph showing power loss after 25 feet of various coax cable types.

Back to Home Page

compiled by Michael Wright, K6MFW. Updated July 10, 2003