2024-07-04

Radio Power and S-Units

Signal Strength

Signal strength meters (S-meters) indicate power levels in S-units.

Each increase of 1 S-unit corresponds to a 6 dB increase, which represents a power ratio of 4:1. This means that a signal that is 1 S-unit stronger is four times more powerful.

dB	Power Increase (x)	S-Unit Increase
1	1.26	0.17
2	1.58	0.33
3	2.00	0.50
4	2.51	0.67
5	3.16	0.83
6	3.98	1.00
10	10.00	1.67
12	15.85	2.00
20	100.00	3.33
30	1,000.00	5.00
40	10,000.00	6.67
50	100,000.00	8.33
60	1,000,000.00	10.00

Signal Attenuation in Coax

Nominal attenuation (dB / 100ft)

Coax	1MHz	10MHz	50MHz
RG-316	3.1	6.0	9.6
RG-58 C/U	0.4	1.4	3.3
RG-8X	0.5	1.0	2.5

Messi & Paoloni attenuation (dB / 30m) (98.43 ft)

Coax	7MHz	14MHz	28MHz
RG-58 C/U	1.2	1.7	2.4
Hyperflex 5	0.7	0.9	1.3
Potaflex 6	0.7	0.9	1.3
Potaflex 7	0.5	0.7	0.9
Ultraflex 7	0.5	0.7	0.9
Hyperflex 10	0.4	0.5	0.6
Hyperflex 13	0.3	0.4	0.5

Loss dB vs Loss Percent

Loss (dB)	Loss Percent (%)
0.00	0
0.25	6
0.50	11
0.75	16
1.00	21
1.25	25
1.50	29
1.75	33
2.00	37
3.00	50
4.00	60
5.00	68
6.00	75

References

https://hamwaves.com/decibel/en/index.html
http://rfelektronik.se/manuals/Datasheets/Coaxial_Cable_Attenuation_Chart.pdf
https://messi.it/dati/layout/attivo/calc_ord.asp?l=EN