Want to calculate your ERP ? This is how.
(1) Add all GAINS (dB) this is your system gain
(2) subtract system loss (dB) from total gains (dB)
(3) convert back to watts
NOTE: Antenna Gain is usually expressed as dBi.
GAINS:
Power dBW (converted from Watts to dBW
using Table below): + Antenna Gain dB = SYSTEM GAIN _____ dB
( see table below )
LOSSES:
CABLE LOSS _____ dB
INSERTION LOSS: (connectors, switches, meters, duplexers, diplexers,
etc.) _____ dB
NOTE: Connectors range anywhere from 0.1 dB to 1.5 dB
(Some pl 259 connectors have measured as high as 1.5 dB loss!)
CABLE LOSS: + Insertion Loss = SYSTEM LOSS in dB ____
SYSTEM GAIN: ______ dB minus SYSTEM LOSS ______ dB
= ERP in dBW ________ (NOTE: This is NOT watts)
ERP: Converted (dBW) to Watts, using Table beolw = ________
Watts
(ERP)
NOTE:
This will not give you the exact ERP of your station!
There are just to many estimates in the calculation. Such as the antenna
gain,
cable loss, connector loss etc.( unless you measure them ) however
it will give you an idea of your station ERP.
Table – Conversion between Watts and dBW
| Watts |
dBW |
Watts |
dBW |
Watts |
dBW |
Watts |
dBW |
| 1 |
0.0 |
40 |
16.0 |
150 |
21.8 |
500 |
27.0 |
| 2 |
3.0 |
45 |
16.5 |
175 |
22.5 |
525 |
27.2 |
| 3 |
4.8 |
50 |
17.0 |
200 |
23.0 |
550 |
27.4 |
| 4 |
6.0 |
55 |
17.4 |
225 |
23.5 |
575 |
27.6 |
| 5 |
7.0 |
60 |
17.8 |
250 |
24.0 |
600 |
27.8 |
| 6 |
7.8 |
65 |
18.1 |
275 |
24.4 |
625 |
28.0 |
| 7 |
8.5 |
70 |
18.5 |
300 |
24.8 |
650 |
28.1 |
| 8 |
9.0 |
75 |
18.8 |
325 |
25.1 |
675 |
28.3 |
| 9 |
9.5 |
80 |
19.0 |
350 |
25.4 |
700 |
28.5 |
| 10 |
10.0 |
85 |
19.3 |
375 |
25.7 |
725 |
28.6 |
| 15 |
10.8 |
90 |
19.5 |
400 |
26.0 |
750 |
28.8 |
| 20 |
13.0 |
95 |
19.8 |
425 |
26.3 |
775 |
28.9 |
| 25 |
14.0 |
100 |
20.0 |
450 |
26.5 |
800 |
29.0 |
| 30 |
14.8 |
125 |
21.0 |
475 |
26.8 |
1000 |
30.0 |
| 35 |
15.4 |
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