04 - Calculating Line Loss
The Longer You Run Cable, The More Signal You Lose. Here's a Way to Evaluate Line Loss.

When installing gear to amplify your mobile signal, so-called "line loss" - the signal you lose by running lines over long distances on your boat - is the enemy. Want to see how line loss works in action? Go to this line loss calculator.

Now compare RG-8 cable against the recommended LMR-400 cable for 1,900 MHz at 50 feet. You should find that RG-8 has a line loss of 5.4 dB at this distance - and that is more than the typical 4 dB cellular antenna will provide in amplification. The line loss negates the utility of the antenna.

Substitute LMR-400 cable, however, and you have a line loss of only 2.9 dB, meaning the 4 dB antenna will add some amplification. As you can see, line loss really matters!

Line Loss Calculator This calculator, available from TimesMicrowave.com, can estimate line loss.