I can't say whether the extended transmit modification "changes to FT-857 with no D". But here is what I believe happens when the modification is made:
The radio has transmit coverage which matches the receive coverage, except no transmit below 1.8 MHz; no transmit in the FM broadcast band; no transmit in the aeronautical VHF band.
There are no special channel positions on the radio for the five amateur 5 MHz channels. However, with the extended transmit capability the five channels can simply be programmed into five of the 200 memory channels.
Two-meter band and 440 MHz band amateur repeater offsets are no longer set automatically. However, any offset can be set before saving a repeater pair into a radio memory.
All memories are erased on the radio... but with CHIRP, you can easily restore your previously programmed memory channels.
For programming with CHIRP, specify FT-857/FT-897 (not FT-857D/FT-897D).
The details on how to make the modification are available online -- e.g., see MARS Modification For Yaesu FT-897D. I understand that upon presentation of proof of MARS or CAP participation, Yaesu technical support will also provide the modification instructions.
David / K7DB
On Wed, Sep 21, 2016 at 8:05 PM, D.J.J. Ring, Jr. <n1ea@arrl.net> wrote:
Is this one of the changes that happens when you open up the FT-857D? I never did that mod because I thought it would no longer work correctly on 5 MHz amateur shared band.