so we have a county-wide ARES activation exercise coming up and i'm trying to get my portable setup dialed in before then. ive done a few of these before but this time i'm actually running the communications node for the EOC so the stakes feel a bit higher than just showing up with a HT and a mag mount.

current plan is to run my IC-7300 off a honda eu2200i with a 40ah lifepo4 battery as a buffer — the generator feeds a battery charger and the radio draws off the battery directly so i dont get that nasty ignition noise bleeding into the audio. worked okay at home testing it but i haven't actually tried it on the air yet.

antenna is where im less confident. thinking a linked dipole for 40/80 since those are the primary nets but the site is a parking lot next to a city building and i have no idea what the RF environment is going to look like or what i have to support the antenna with. was going to bring a couple of 20 ft painters poles and stake them out but that feels marginal for 80m. anyone run a setup like this in a parking lot situation and have thoughts on what actually works vs what sounds good at home?

also genuinely not sure how long to plan on running the generator vs just sitting on battery alone. exercise is supposed to be 6 hours but you know how those go.

the generator isolation thing you described is smart, that's exactly what i do. the eu2200i is pretty clean to begin with but you still get hash on certain bands especially if the load changes — running the radio off the battery with the charger maintaining it eliminates like 90% of that headache. just make sure your charger itself isnt noisy, some of those smart chargers are awful on 40m.

on the antenna question — painters poles work but they're a pain to keep vertical without a lot of guying and in a parking lot you dont always have great anchor points. i've had decent luck with a telescoping squid pole lashed to whatever is already there, a fence post, a sign pole, whatever. for 80m you kinda need the height anyway so even getting the center up 25ft helps more than you'd think. linked dipoles are a solid choice, more so than a trap dipole for multi band field work in my opinion just because there's nothing to break or get waterlogged.

for the 6 hour exercise on battery alone, a 40ah lifepo4 running a 7300 at maybe 60-70% of rated draw you're probably looking at 4-5 hours comfortable depending on how much you transmit. i'd run the generator for an hour mid-exercise to top off and then you're fine. no reason to run it the whole time if you dont have to, saves fuel and your ears.

yeah parking lots are rough, did a similar thing last spring for a simulated emergency test and the RF noise floor from the building HVAC alone was like S5 on 40. you might want to bring a noise canceler or at least be mentally prepared to fight it. the linked dipole should help since you can actually null some of that junk with orientation but it takes some fiddling to figure out once you're on site.

one thing i'd add — bring more coax than you think you need. every single time i think i've got enough feedline i end up 10 feet short because the anchor points arent where i assumed. just throw another 50ft section in the truck.