so i've had my FT-857D for probably 6 years now and always ran it stock because i was nervous about voiding warranty and whatever but the warranty is long gone and i finally just did it. did the mars/cap mod to open up the TX range and honestly it was way less scary than i expected. just the one diode removal on the main board, took maybe 20 minutes if you count the time i spent staring at the service manual trying to convince myself i was looking at the right spot.

anyway the main reason i wanted to do it was for some NVIS work on 60m outside the standard allocations we use for emcomm stuff, and also just wanted the flexibility. the mod itself works fine, no issues at all. but what i actually want to ask about is whether anyone has done the extended RX mod too — i've seen a few different versions floating around and some of them involve jumper changes and some seem to just be software. not sure which way to go or if it's even worth it for HF since i already have a dedicated SDR for wideband monitoring

yeah I did both mods on mine back when i first got it, probably 2013 or so. the RX mod is worth doing imo just because the 857 actually recieves pretty decently below the broadcast band and you get coverage down into the longwave stuff which is fun to poke around on. the jumper version vs software thing — i went the hardware route because i didn't fully trust the software only approach, seemed like it could get reset by a firmware update or factory reset. with the physical jumper change it's just done and stays done. there's a thread on eham somewhere that lays it out pretty well, look for the one by KD9 something, forget his suffix. just make sure you're looking at the right version of the board because they changed the layout somewhere around 2009 i think and some of the older diagrams are wrong for the newer units

tangentially related but if you're doing mods anyway and you haven't replaced the stock mic element you're leaving a lot on the table. i put an electret element in mine and the audio reports went from mediocre to actually good. its a cheap mod, under 5 bucks in parts, and you don't have to touch anything on the radio itself. combined with tweaking the TX EQ in the menu it made a noticeable difference on sideband. just something to consider while you've already got the itch to modify things