Archive for June, 2008
FM radio amplifier 25W
A simple 25W fm radio amplifier used as a final stage for a 2.5W transmitter. I has a total gain of 10 dB and needs a 12V / 3A power supply. It is equiped with KT925W or BLY88, BLY89C. Use a very good headsink because this transistor get very hot
Coils values:
L1 = L3 = [...]
Amplification factor, power gain and dB
To find the power gain ratio corresponding to a 3 dB change in level, use the formula:
The table showing the amplification factor if you know the power gain in dB
FM antenna amplifier
Use this fm antenna amplifier in areas where the signal reception of FM stations is too bad.
This circuit is just the right thing to do it. It is designed in such a way that the supply current powering it flows through coaxial cable. With this technique, an extra cable to power the fm antenna amplifier [...]
