The RPCB 144ub is the replacement board for the Yaesu FT221 and the FT 225 transceivers. It is supplied with complete installation instructions as well as interconnecting cables. The board replaces the original board in the transceiver and is the simplest of the front end kits to install. This board features a low noise front end, Tchebyshev bandpass filters, diode ring Double Balanced Mixer (DBM), IF amplifier plus an 6 pole 15KHz crystal filter. No alignment is necessary after installation of the board.
Frequency Range 144.0 MHz ~ 148.0 MHz
Emission: AM FM SSB (LSB and USB) and CW
SSB 12 Watts PEP
FM, CW 14 Watts
AM 2.5 Watts
The frequency is set by a 500KHz VFO being mixed with the product of a number of crystals and is displayed using a rotary display dial.
The top of the case is removed by opening 4 quick release fasteners, revealing a number of user adjustable trimmers and pots. The modular design of the FT-221, where removable circuit boards allowed radio hams to modify their FT-221 either by replacing specific components or even replacing the whole board [Mutek]. One such replacement is the mutek replacement front end board which improved the front-end sensitivity. The open format of the internal construction also allowed the transmit and receive cables to be brought outside the case to use a low-noise coaxial relay.
Below is the Mutek direct plug in replacement Front End Board for the FT-221 transceiver: