DB GAIN CHART
|
Antenna Gain
|
Watts Multiplier
|
ERP with 100 Watts Input
|
|
1
|
1.2
|
120
|
|
2
|
1.6
|
160
|
|
3
|
2.1
|
210
|
|
4
|
2.5
|
250
|
|
5
|
3.2
|
320
|
|
6
|
4
|
400
|
|
7
|
5.1
|
510
|
|
8
|
6.3
|
630
|
|
9
|
8
|
800
|
|
10
|
10.2
|
1020
|
|
11
|
12.6
|
1260
|
|
12
|
15.9
|
1590
|
|
13
|
20
|
2000
|
|
14
|
25.1
|
2510
|
|
15
|
31.6
|
3160
|
|
16
|
39.9
|
3990
|
|
17
|
50.2
|
5020
|
|
18
|
63.3
|
6330
|
|
19
|
79.5
|
7950
|
|
20
|
100
|
10000
|
Remember that when calculating the ERP of your station you must take into account all antenna system gains and losses, including feedlines, connectors, adapters, etc.
Example: if you have an antenna with a 7 db gain, coax with the calculated loss (based on type, length, and operating frequency) of 2 db, and total connector losses of 1 db, you have 7-2-1 = 4 db of gain. Thus, if your rig is transmitting 100 Watts peak, you will have a peak ERP of 100 x 2.5 (multiplier) = 250 Watts.
Need to calculate your coaxial cable losses based on coax type, length, and operating frequency? Here is the link to a very handy coaxial cable loss calculator. Clicking on it should open the calculator in a new browser tab/window, which you can simply close when you’re done and this page should still be visible.