so i finally got a chance to deploy a proper field comms setup last weekend for a county ARES exercise and ran into a few things i wasnt expecting. figured id post here since ive been lurking forever and maybe someone has dealt with this stuff before.

the big one was RFI from the generator. we were running a Honda EU2200i which i thought would be pretty clean but man it was pumping garbage into the 40m receive chain something awful. i had the genny about 30 feet off to the side of the station and still getting S3-S4 noise on the lower part of the band. tried a common mode choke on the power line going into the station but it only helped a tiny bit. is 30 feet just not far enough or is there something else going on, like maybe the fuel line or frame is picking up ground loops or something.

second thing was antenna placement. we were in a park with some decent trees but the only clear run for the 40m dipole was kind of parallel to the main road which put it basically pointing toward the EOC we were supposed to be working. i know you want the ends away from where youre trying to talk but we didnt have a lot of options. ended up being like 30 degrees off from ideal. signal reports were okay but not great, wondering if a vertical wouldve done better in that spot or if we should have just dealt with the extra feedline to get a better orientation.

also running off a deep cycle AGM and the generator to charge it - is it worth bringing a second battery instead of the genny for a 6-8 hour exercise or does the math just not work out for 100w HF ops.

the generator noise thing is almost always a grounding issue in my experience. 30 feet of separation sounds like enough but if youre running an extension cord from the genny to your rig that cord is basically acting like a big antenna for whatever the inverter section is spitting out. what i do is put the genny as far as the cord will allow, then use a good line filter right at the rig end not the genny end, and most importantly make sure you have a solid RF ground on the station chassis separate from the power ground. the EU2200i is inverter based so its supposed to be clean but ive seen them get nasty especially when theyre under partial load or the ground bonding isnt great.

on the battery question - honestly for 6-8 hours at 100w you need to think about your actual duty cycle. if its an exercise with a lot of listening and occasional transmissions you might burn through 20-30 AH which a decent 100AH AGM handles fine. but if youre doing heavy traffic handling or net control with long overs it adds up fast. id bring two batteries and leave the genny home if you can swing it, way less noise headache and you can focus on operating instead of babysitting a machine.

yeah the dipole orientation thing bugged me for a long time until someone explained that at typical NVIS angles on 40m the pattern is way more forgiving than the textbook figure-8 makes it seem. if youre doing NVIS to hit an EOC a few hundred miles away the polarization and orientation matters less than you think, most of the signal is going almost straight up anyway. where it really bites you is if you need a low angle shot, like if the EOC is 800+ miles out and youre trying to use skip. then yeah a vertical or getting the dipole oriented right would matter more.

for what its worth i ran into almost the exact same genny noise problem at a RACES drill a couple years back. ended up wrapping the power cord through a big clamp-on ferrite a few times right where it entered the tent and that made a noticeable difference on top of what a choke on the coax was doing. might be worth trying a few in series if you havent already.