so our ARES group has a county-level exercise coming up in about 6 weeks and i've been tasked with figuring out the power situation for our primary station. we're setting up at a fairgrounds site, no shore power available except one outlet in a building that's maybe 300 feet from where we want to actually operate, which is basically useless.

right now the plan is to run an IC-7300 plus a 2m/70cm setup, maybe a laptop for logging, and some odds and ends. not running a linear so total draw shouldn't be crazy but i'm trying to figure out if a generator is overkill or if we should just go deep cycle batteries and a decent solar panel or two since the forecast looks pretty good for that weekend.

the antenna situation i have mostly figured out — setting up a linked dipole for HF that i can adjust between 40 and 20 depending on what nets we're assigned to, and a jpole up on a mast for the vhf stuff. the jpole is just a roll-up copper one ive had for years, works fine. the dipole is the one i built last winter, havent had any problems with it but also havent really stress tested it in a field environment with people walking around and bumping into things.

main question is really around the power. anyone done extended field setups like 8+ hours without a genny? what are you actually pulling in amp hours when you're doing like moderate tx duty cycle? i know the math but i always feel like real world is different than what i calculate on paper.

yeah the real world numbers are usually worse than your calc, at least in my experience. mostly because you forget about all the little parasitic draws — the laptop, the fans if it gets warm, USB hubs, whatever clock or logging device you're running. i've found i usually add about 15-20% on top of whatever i estimate and that gets me pretty close.

for 8 hours with a 7300 doing moderate SSB work, rough guess maybe 60-70 ah depending on how hard you're pushing it. if you have two 100ah AGM batteries you're probably okay but not with a ton of headroom. lithium obviously changes that math significantly, you can actually use more of the rated capacity without killing the battery. we switched to a 100ah lifepo4 for our portable kit last year and it made a noticeable difference in how long we could actually run.

one thing i'd strongly suggest — test it before the exercise. like actually run your full setup in your driveway for 4-5 hours on a battery and see what you pull. bring a current meter or even just check terminal voltage regularly. nothing worse than finding out on the day that your load estimate was way off.

on the generator question — if it's an 8 hour exercise i'd probably still bring a small genny as a backup even if you're going solar/battery. a 2000w inverter type genny is quiet enough that it's not obnoxious and it'll save you if clouds roll in or something else goes sideways.

dont overthink the antenna side if the linked dipole is working. for emcomm exercises the contacts are usually short and the bands are going to be semi-predictable since everyone knows which frequencies ahead of time. ive run 40m inverted V from a painters pole in the back of a truck and it worked fine for a full day exercise.

the generator vs battery thing really comes down to how much your group wants to carry and deal with. generators are great until they need fuel or someone forgets to check oil and it seizes up, which ive seen happen. batteries are quiet and simple but yeah you gotta know your numbers. solar is nice as a trickle but i wouldnt rely on it as your primary source for an 8 hour op, too many variables.