David Parker

yeah the missing balun is almost certainly part of your problem. without a choke at the feedpoint the coax shield becomes part of the radiating system which throws everything off and can cause weird SWR readings that shift when you touch the coax. i went through the same thing with my first 80m dipole. wound a 1:1 choke on a FT240-43 toroid, like 9-10 turns of the coax, and the SWR dropped and stabilized noticeably. 1.8:1 isnt going to hurt anything but its definitely worth sorting out the common mode problem first before you start trimming because you might end up chasing your tail cutting wire based on a reading thats being influenced by the coax anyway.
also 25 feet on 40m is gonna give you more NVIS-ish radiation which isnt the worst thing depending on what youre trying to do. if youre working regional stuff its actually fine. for DX youd want it higher obviously but work with what you got.

Yeah I've been there too. Sometimes you gotta restart both programs in the right order - WSJT-X first, then N1MM. Also double check that "accept UDP requests" is enabled in N1MM under the digital interface tab. Pain in the rear when it stops working randomly but usually its something simple

the relay theory is pretty solid, that's where i'd look first too. one thing i'll add — on the 857 specifically there's been some talk on eham about the SMD capacitors in the front end going leaky over time, especially on older units that ran hot. not super common but worth keeping in mind if the relay checks out okay. the service manual for the 857 is honestly pretty good once you find the right version, there were a few revisions. if you can get a signal tracer or even just a cheap RTL-SDR to inject test signals at different points in the chain you can usually narrow it down pretty fast without just swapping parts blind.

so i finally did my first activation last weekend, been chasing summits for about 6 months and kept telling myself id get out there and actually do one. picked a relatively easy summit nearby, W4T/SU-031 if anyone knows that area, figured it would be a good starter since the trail isnt brutal and the summit reference had been activated a few times before so i knew it was legit.
brought my FT-818 and a linked dipole i built from a kit, got to the top and started setting up and immediately the wind picked up like crazy. spent probably 20 minutes just trying to get the antenna sorted before i could even think about making contacts. posted my spot on SOTAwatch and waited and honestly thought nobody was going to answer me on 40m, the noise floor up there was surprisingly bad considering im on top of a hill.
eventually moved to 20m and started getting some responses, managed 4 contacts which i know is the minimum but it still counts right. one of the chasers was super helpful and told me to try calling CQ a bit slower which i think did help. came down feeling kind of mixed about it but also kind of hooked if that makes sense. anyone else have a rough first activation that still worked out?

yeah the engine noise on certain rpms is almost always the coax routing, i had the exact same thing with a door jamb setup on my old chevy. once i rerouted it properly and used a ferrite bead near the radio end it was basically gone. that said i still havent drilled my current car so im not one to talk lol

honestly the General exam is not as bad as it looks when you first open the question pool. i went from Tech to General in maybe 3 weeks of casual studying, maybe 30-45 minutes a night with HamStudy.org. that site is pretty much all you need, it tracks which questions you keep getting wrong and drills you on those. the electrical theory stuff like the impedance questions and the resonance formulas look scary but theres really only so many ways they can ask it and once you see the pattern its fine.
the band plan stuff does start to make more sense once you get even a basic feel for propagation, like why 40m is good at night and 10m can be dead for years and then suddenly open up and you're talking to australia on 5 watts. but for the exam honestly just memorize the phone and CW segments, the question pool repeats itself a lot on that. the propagation questions are actually kind of interesting once you get into it, stuff about the ionosphere and skip distance. i found myself actually wanting to learn that part rather than just cramming it.

the KX2 is such a nice little rig for portable ops, good choice. i take mine out for SOTA activations and its been rock solid. one thing i'll say about the whole building vs buying thing — i built a pixie kit just to say i did it and while the radio itself is kind of a toy it really did teach me a lot and cost almost nothing. now i kinda understand what's actually happening inside the box which makes the KX2 make more sense to me too if that makes sense.

been using RemoteHams for almost a year, came from the hamradiodeluxe remote thing which was a disaster for me. the latency on fixed wireless should be totally fine, ive operated through a Starlink connection at a friend's place and even the jitter wasnt that bad once you set the audio buffer a bit higher than default. there's a slider in the client for it, dont leave it on auto if your link isnt rock solid.
honestly my only gripe is when they have server issues the whole thing just dies and theres not always great communication about it. had a contest weekend where i lost the connection for like three hours and couldnt do anything. with a DIY setup at least you can reboot stuff remotely or figure out whats wrong. so there's a tradeoff. but for casual operating and not wanting to babysit the setup all the time its pretty solid.