Gain - is simply a term that explains how to measure a signal.
http://www.hdtvprimer.com/ANTENNAS/types.html
http://www.hdtvprimer.com/ANTENNAS/G...ml#capacitance
http://www.hdtvprimer.com/ANTENNAS/basics.html 20 dB = gain factor of 100
10 dB = gain factor of 10
3 dB = gain factor of 2 (actually 1.995)
0 dB = no gain or loss
-1 dB = a 20% loss of signal
-3 dB = a 50% loss of signal
-10 dB = a 90% loss of signal
http://en.wikipedia.org/wiki/Antenna_gain
http://www.tech-faq.com/television-antenna.shtml