The Yaesu FT-817 is one of the smallest MF/HF/VHF/UHF multimode general-coverage amateur radio transceivers. The set is built by the Japanese Vertex Standard Corporation and is sold under the Yaesu brand. With internal battery pack, on board keyer, its all mode/all band capability and flexible antenna, the set is particularly well suited for portable use. The FT-817 is based on a similar circuit architecture as Yaesu's FT-857 and FT-897, so it is a compromise transceiver and incorporates its features to its low price ($670.- at its 2001 release). The upgraded FT-817(N)D was launched in 2004. The difference between the two models is the addition of 60 meter band coverage in 5 fixed channels (USA model only), other display lighting options, modifications in the RF stage, the included FNB-85 battery-pack and NC-72B charger. The FT-817 is a QRP transceiver. The FT-817(N)D is no longer in production, and has been replaced by the FT-818, which improves on the previous model with an increase of RF output from 5 to 6 Watts, higher capacity battery and the inclusion of a TCXO for better frequency stability. In December 2022 Yaesu announced they were also discontinuing production of the FT-818. Technical description CAT interface A serial port with a wide range of commands is provided. Circuit description The following circuit description is an extract from the service manual RX signals may be input via a front BNC connector or a rear UHF SO-239 connector (Yaesu calls it a type "M" connector) using a relay on the PA unit. The selection has to be made per band (HF, 6, 2 m or 70 cm) using menu selection. The BNC connector is the antenna connector chosen when the relay is bypassed. A 70cm signal path goes through a high pass filter network, through the RF directional coupler/power detector (not on rx) to a low pass filter to a PIN-diode. In rx mode, these are turned off. The rx signal then passes through a DAN235U; this is a dual diode and when in UHF rx mode, the appropriate diode is turned on, passing the 70 cm signal through and the signal then leaves the PA board. On the MAIN circuit board the 70 cm rx signal enters a DAP236U. This dual diode get its current from the PA unit and when 70 cm rx mode is active one of the diodes is turned on. Rx signal goes through