Low Pass Filters
Unfiltered amplifiers are illegal for on-the-air use!
The low-pass filters designs on this page clean up the output of amplifiers up to 100W.
When used with the MRF-101 eval board produce a signal that meets or exceeds FCC requirements.
RF Power Tools currently has two low-pass filter board options for the 100W amplifier deck. A three band version and a seven band version.
3 Band LPF Design:
The 3 band LPF is in a 5 X 5 cm (~2" X 2") which is designed to stack with the 100W MFR-101 eval board and the 100W T/R switch boards to make a compact, complete 100W amplifier.
Builders must select 3 of the available filter designs to complete the filter board. Avaiable designs are:
- 6M - 10/12/15M - 17/20M
- 30/40M - 60M - 80M
- 160M
When fitted with the 3 band LPF, the amplifier can be used on the bands covered by the selected filters.
7 Band LPF Design:
When fitted with the 7 band LPF, the amplifier can be used on all Amatuer bands from 1.8 to 54 MHz
Header Pinout:
Pin 1: 11-15VDC 13.8V Nominal, 100 mA max.
Pin 2: Band select Bit 0 (LSB) High = 2.4 - 5.0V; Low 0 - 0.5V; Pulled to 5V with a 10K
Pin 3: Band select Bit 1
Pin 4: Band select Bit 2 (MSB)
PIN 5: N/C
Pin 6: Ground
Band Select:
The 7 band LPF is in a 10 X 7.5 cm (~4" X 3") which is designed to be used with the 100W MFR-101 eval board and the 100W T/R switch boards to make a compact, complete 100W amplifier.
