Modifications for the Yaesu
FT-211
19-07-1998 9600 BPS with Yaesu
FT-211RH
The FT-211RH has been shown to be suitable for 9600 baud
packet operation. There is no major surgery required just two screened leads are
required, one for TX AF the other for RX AF connected as follows:
RX
AUDIO
On the RX IF Unit (sub board F2869104) connect the screened lead
inner to the TK10420 IC pin 9 with the outerscreen to pin 15. Caution should be
taken to solder these if soldered to the underside of the board.
TX
AUDIO
On the rear of the main PCB a small potentiometer will be seen
(peak deviation adjuster). Unsolder the leg nearest to the rear of the set, and
connect the inner of the screened TX leads to this point, the outer to the earth
plane adjacent to this point. To ensure that the 9600 baud modem is terminated
in the required impedance, it is essential that a suitable terminating resistor
be placed across the screened lead inner/outer, eg a 560 ohm resister; this may
usefully be done at the FT-211RH potentiometer connection.
No further
adjustments need to be made to the radio. On the tested modem a suitable level
of 2.5 kHz deviation was achieved with one third rotation clockwise of the modem
TX AF level potentiometer.