so ive been sitting on doing the mars/cap mod on my FT-857D for probably two years now, always chickened out because i didnt want to brick a radio i actually depend on for portable ops. finally just did it last weekend and honestly it was way less scary than i built it up to be in my head. two diodes, about 20 minutes, done.

what i actually wanted to post about though is that while i had it open i also went ahead and did the ref oscillator mod with the TCXO unit. and that part i do think made a noticeable difference, especially on digital modes. the frequency stability was always a little annoying on FT8 when the radio was cold, like it would drift for the first 10-15 minutes until everything warmed up. that seems basically gone now. i know some people say you cant really tell the difference but i can at least on this radio.

anyone else done both at the same time, curious if your experience was similar or if maybe i just got lucky with a particularly drift-prone unit before

yeah the TCXO on the 857 is worth it, i did mine maybe 3 years ago and same thing you describe with the warmup drift, it was driving me nuts on PSK31 back when i was doing a lot of that. the mod itself is straightforward but i remember the connector on the replacement unit being slightly fiddly to seat properly. if anyone reading this does it just make sure you dont force it.

i never bothered with the MARS mod on mine since i dont really have a use for out of band TX but i get why people do it just to have the flexibility. the 857 is such a capable little radio thats kind of underrated honestly, people sleep on it because its older but it does a lot for its size.

interesting, i have an 897D not the 857 but they're pretty similar internally from what i understand. been meaning to do the TCXO swap for a while. does it require any realignment after or does it just drop in and work? i dont have a signal generator at home so if it needs cal work thats kind of a pain for me