The set is built by the Japanese Vertex Standard Corporation and is sold under the Yaesu brand.
[1][2] 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).
[4] The FT-817(N)D is no longer in production, and has been replaced by the FT-818, which improves on the previous model with an increase of RF output from 5 to 6 Watts, higher capacity battery and the inclusion of a TCXO for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.
Rx signal goes through a device consisting of 2 back-to-back diodes providing protection for the receiver's front end.
The output of the filtered and amplified 70 cm path is passed through and coupled into the receive mixer.
These diodes and related components form T/R isolation switches that operate similar to that of the 70 cm front end.
Here the signal enters and then passes through a transformer, along with a varactor and related components and forms an electrically-tuned filter/matching network, the 2 meter preamplifier.
On the MAIN unit, it goes through the same part as the 2 m signal, but it then goes through the diode portion that was not used for 2 m into an electronically tuned bandpass filter.
The PIN diode bias is provided by the PA unit and flows through the primary transistor.
For 6 m the hi-pass filter includes a preamplifier (always used on 6 m rx and not affected by the IPO menu setting).
Emtech ZM-2 small, lightweight manual Z-match tuner for balanced and unbalanced feedlines Vulnerable final transistors in non-ND model!
The 2SK2975 FET's in the final stage are VERY sensitive and can easily be destroyed by high SWR, overheating, overvoltage, or voltage peaks.