YAESU FT817 FT818

The Yaesu FT-817, 818 is a very popular QRP transceiver and interfaces with the HR50 amplifier for PTT keying and automatic band selection. The FT-817, 818 provides an analog voltage output the level of which indicates the transceivers band setting. The HR50 can read this voltage level and set the amplifier’s band accordingly. If the FT-817, 818 is operating on a band that is not supported but the HR50 (2m and 70cm) the amp will display UNK for the band and remain in bypass.

FT-817 Mode must be enabled in the HR50’s menu to support automatic band selection. HR50 amplifiers with serial numbers below 1200 do not support FT-817 band selection using this technique

The following drawing shows the required connection: