so ive been putting this off forever but finally cracked open the 857D last weekend to do the extended TX mod. you know the one, just moving a couple diodes to open up the transmit range outside the normal band limits. pretty straightforward if you follow the right diagram and dont rush it.

anyway the actual mod took maybe 20 minutes once i had everything laid out and a decent light on the board. the tiny SMD diodes are a pain but doable with steady hands and a fine tip iron. what i wasnt expecting was how much better the fan mod helped at the same time — ran a 12v fan mod off the same session since the board was already out, and that thing used to get pretty warm running digital modes for any stretch of time.

my question is really for anyone who's gone further with this radio — i've seen people talking about the ref osc mod for better frequency stability and i'm kinda tempted. does it actually make a noticeable difference on like, normal SSB and FT8 use or is it more of a contest/weak signal thing? feels like the stock osc is already pretty decent but i dunno, maybe im just not noticing drift because im not doing anything that demanding.

the TCXO upgrade on the 857 is worth it if you do any digital stuff at all honestly. stock oscillator on those is fine for voice but when youre trying to hold a tight FT8 decode window and the rig drifts even 5-10 hz over a long session it starts to matter. i put the TCXO in mine about two years ago and the difference was immediately obvious in WSPR — before the mod i'd see the trace wander on the waterfall, after it was basically a straight line.

the fan mod you mentioned is probably more practically useful day to day though. those rigs really do cook themselves if you push them on digital. i had one that went intermittent on TX and it turned out to be a thermal issue, never ran it hot again after that.

yeah dont bother with the osc mod unless you're doing serious weak signal vhf or something where every hz counts. for normal HF use its overkill. the fan mod tho, that i'd do on every single one of those radios before anything else. good call doing them together while you had it open.