so ive been running my 7300 for about two years now and always kinda wondered about the TCXO upgrade. the stock oscillator is fine honestly but i do a lot of digital modes and FT8 especially and i kept reading threads about how the frequency stability improves noticeably with the TXCO-2 option unit installed. finally bit the bullet last weekend and did it myself, the install is pretty straightforward once you pull the top cover, just a small board that drops into a socket near the front left if i remember right.

honestly the difference on the waterfall is pretty visible to me. before i'd occasionally see my own signal drift a tiny bit over a long FT8 session especially when the rig was still warming up, now it just locks in and stays. could be confirmation bias i guess but i dont think so. also noticed the CAT control feels a bit snappier but that might be unrelated, maybe i just imagined that part.

anyway wondering if anyone else has done this mod or any other internal upgrades to the 7300. i know some people do the fan mod too to quiet it down, havent messed with that yet. curious what people have found actually makes a difference vs stuff that sounds good on paper but doesnt change much in practice.

yeah the TCXO on those rigs is a legit upgrade, not placebo. i put one in mine maybe 8 months ago and the drift on cold startup is basically gone now. before i had to let it warm up for like 20 minutes before running any serious digital work or my decodes would be iffy in the first few minutes. that warmup thing annoyed me way more than it should have.

the fan mod is worth doing if the noise bothers you, i replaced mine with a Noctua fan that someone did a write-up on eHam about, cut it to fit and ran it through a small resistor to drop the voltage a bit so it spins slower. way quieter and the rig still runs cool. only thing is you gotta be careful with the connector, the stock fan uses a specific plug and its a little tight in there. not a hard mod but definitely need to pay attention to what youre doing.

one thing i keep meaning to do but havent gotten around to is the PA transistor check — theres a procedure where you can measure bias on the finals and some people say the factory setting runs a bit cold. supposedly setting it a bit higher improves IMD. havent pulled the trigger on that one yet since the rig is working well and i dont want to mess with something that isnt broken.

did the TCXO on my 705 not the 7300 but same idea basically. definitely real improvement for digi modes, you can actually see it if you pull up a stable reference signal and watch over time. the stock xtal is just kinda meh for tight-tolerance stuff.

havent done much else internally, mostly just external stuff like a better mic element and swapping the stock hand mic for a desk mic. those changes honestly made more of a practical difference for phone operation than anything inside the box would. but for FT8 and JS8 yeah the TCXO pays for itself pretty fast.