Yaesu FT-847 Operating Manual

Also see for FT-847: Technical supplement Technical supplement Technical supplement Modification

Contents

18 FT-847 OPERATING MANUALCW Accessory InterfacingAll commonly-available keyer paddles should workperfectly with the built-in Electronic Keyer. The wir-ing configuration for the paddle is shown below.For straight-key operation, only the tip and shaft con-nections are used.Note: Even when using a straight key, you must use athree-conductor (“stereo”) plug. If a two-con-ductor plug is used, the key line will be con-stantly shorted to ground.When using an external electronic keyer, be absolutelycertain that it is configured for “positive” keying, not“negative” or “grid block” keying. The “key-up” volt-age of the FT-847 is +5V, and the “key-down” currentis only about 2 mA.For CW automated keying using a personal computer,with an external memory keyer providing for manualsending, it usually is possible to connect the keyedlines together via a “Y” connector, as shown below.Check with the documentation accompanying yourkeyer and your contest/DX software for any cautionswhich need to be observed.InstallationACCESSORY INTERFACINGReceiver Accessories(TAPE RECORDER, WEATHERFAX DEMODULATOR, etc.)For weak-signal VHF work, including meteor scatterand EME (Moonbounce), it often is desirable to recordyour contacts for future reference. During high-speedCW meteor-scatter schedules, tape recording (or feedof RX Audio to a computer) is required for decodingof the incoming signal bursts.Connection of a tape recorder, WeatherFax demodu-lator, or other receiver accessory is easily accomplishedusing the DATA IN/OUT jack’s Ring connector, asshown in the illustration below. The audio output levelis fixed at 20 mV with an impedance of 10 kΩ.