Anthony Davis

the waterfall thing is real, i had the same reaction when i got mine. dismissed it as a toy feature for a long time and then realized i was using it basically every single QSO to check for QRM before transmitting. the 7300 kinda changed how i operate without me really noticing it happening.
on the receiver comparison — i think what youre picking up on is real. the 590 has a slightly different front end topology and some guys who do careful comparisons say it holds up better in very dense band conditions. but for most operating the 7300 is totally fine and the SDR based architecture gives you things the older design just cant do. tradeoffs everywhere.
what antenna you running it into? im curious how the built in ATU is handling things for you, mine sometimes needs a little coaxing on 60m with my doublet.

yeah the America/Adam/etc thing is the old "able baker" phonetics from before NATO standardized everything in the 50s. you still hear some old timers using them, mostly guys who learned on AM back in the day. not wrong exactly but it can cause confusion if the other station isnt familiar with it.
as for when to use them -- honestly its just conditions and context. on a clear local repeater with a strong signal theres no real need to phonetic out your whole callsign every time, people can hear you fine. but on HF especially when the band is marginal or youre working DX, phonetics are genuinely useful because certain letters just sound identical through static and QRM. B and D, M and N, S and F... they all smear together. so most operators just develop a feel for it. if you have to repeat yourself, thats usually a sign you shouldve gone with phonetics from the start

so ive been putting this off for like two years because i was nervous about opening up the radio but finally just did it last weekend. pulled the mars/cap mod on my FT-857D so i can cover the extended TX range and also went ahead and did the collins filter swap while i had everything apart. took me about 3 hours which is embarrassing because honestly its not that complicated once you get the covers off.
the filter swap made a way bigger difference than i expected on SSB receive, the stock filter is honestly pretty mediocre and i dont know why yaesu still ships these with it. also redid the mic gain and processor settings after because the defaults seem kinda off after the mod, not sure if thats just coincidence or if i bumped something.
anyway if anyones been on the fence about doing this, at least the filter part, its worth it. just take your time with the connectors on the display assembly because those ribbon cables are not happy when you force them

yeah i did almost the exact same thing for my first antenna, 40m dipole with whatever wire i had. one thing nobody told me that i wish they had — the trees move. like obviously they move in wind but i mean they also grow and shift and the tension on your rope changes with seasons. first hard wind i had my whole center piece came down because i didn't leave any slack in the feedline drop. just something to think about when you're rigging it up, give yourself a little droop in the coax so it doesn't pull the connector.
RG-8X over 50 feet on 40m is totally fine loss wise, dont worry about that.

yeah the first minute is basically always wasted, dont feel bad about it. even with a full az/el setup and gpredict driving the rig via hamlib it still takes me 20-30 seconds to get oriented when the sat comes up. the difference is at least im not also fighting doppler manually by then.
the inverting transponder thing on FO-29 just takes repetition honestly. you tune up on the uplink, signal goes down on the downlink, brain eventually accepts it. what helped me was just spending a few passes not even trying to work anyone, just listening and watching how my signal moved. also USB on the downlink pretty much always even though youre sending LSB up, thats the rule of thumb for inverting transponders and once it clicks it clicks.
AO-73 has been frustrating lately, youre right to be skeptical. stick with FO-29 for now or look at the SO-50 passes for FM just to get reps in on tracking without also fighting the linear transponder learning curve at the same time.

yeah im planning on going, my buddy from the repeater club mentioned the swap meet portion is gonna be bigger this year cause they moved to the fairgrounds instead of the VFW hall. should be way more table space. I always end up spending more than i should on coax and connectors i dont need but hey thats half the fun right

this is something i struggle with bad. i mostly do digital modes now because i got so frustrated with pileups lol but even on FT8 working a rare entity during a DXpedition is its own kind of chaos — the log fill rate goes nuts and if your signal isnt getting decoded consistently youre just spinning your wheels.
one thing i read somewhere was about working split even on FT8 which i hadnt really thought about before, like choosing a less congested TX frequency in the DX's listening window. makes sense in theory. havent fully figured out the timing thing on digital the same way you described for CW though, its a bit more mechanical with the 15 second slots. anyway good write up, gives me stuff to think about for when i do try SSB or CW pileups more seriously.

not sure if this applies but i once chased a similar issue on a different radio for like two weeks and it ended up being a cracked solder joint on one of the switching diodes that selects the band filter. super tiny crack, looked fine visually until i hit it with good lighting and magnification. might be worth a close look at the band switching section if you havent already, especially if the radio's seen any thermal cycling or been dropped at some point. those hairline cracks are annoying to find but easy to fix once you see them.