SAT inline amp modification for weak signal operation
| you can buy cheap "inline-amps" for TV-SAT. they are wideband 900-2400 MHz, some also work in the 47-2400 MHz range. these amps are crap for weak sigal operation. with 2 of them my L-band setup works better but the noise increse a lot. the worst model i own is equeiped with a 6 pin IC-amp, thats the first i modified. |
|
 |
original amp with removed backplane.
i could not identify the original the 6 pin chip. it makes the gain, and also a lot noise.
note the 18 ohms (R 1) resistor in the input line, it seems to match 75 to 50 ohms for the IC input. it's not needed in a 50 ohms system |
|
 |
desoldering the ferrit coils and the chip gives a better view to the layout.
minimal changes where made. the circuit around the Z-diode delivers 6 volt and leaved unchanged.
C1, R1, C2 and C3 can be changed to an optional input filter for equaliseing the frequeicy response. |
 |
| i changed it to RAM6+ from mini circuits. gain = 11 dB @ 2 GHz, NF = 2.8 dB |
 |
the new circuit
i removed R1, C2 and C3. |
 |
| 9.7 dB gain on 1.5 GHz. |
|
|
