so ive been licensed for about 8 years and done a fair bit of DX on HF but lately ive been obsessed with the idea of doing EME on 2m. i know its a rabbit hole and ive been reading everything i can but theres a gap between reading about it and actually understanding what i need to get started without just throwing money at a wall.

my current 2m setup is just a pair of M2 2M5 yagis on a small az/el mount, running about 400w into them. i know thats pretty modest for EME but ive seen people claim you can work stations with JT65 and a single yagi if conditions are right and the other station is running a big array. is that actually realistic or is it one of those things people say but dont really mean

also the noise floor thing confuses me a bit — i understand you want as low a noise figure as possible at the preamp but how much does that actually matter in practice if the sky noise at moonrise is already elevated. like is going from a 0.5dB NF preamp to a 0.3dB NF preamp actually going to matter or is it splitting hairs at that point

any of you who've actually done EME contacts would appreciate hearing what your first contact was like and what you were running

yeah so the single yagi thing is technically true but heavily depends on who you're working. there are stations running 4x10 element yagis and kilowatts that will pull out weaker signals than you'd think possible with JT65, so if you get in the log with one of those guys running 200-400w and two yagis it can happen. my first EME contact was with OH2PO back when i had 4x9el yagis and about 600w, and even that felt marginal at times. the path loss on 2m EME is something like 252dB on a good day and JT65B gives you maybe 28-30dB over CW so the math does work out but you're really at the mercy of the other stations antenna and preamp situation.

on the NF question — honestly at 2m the difference between 0.3 and 0.5 is probably not going to change your life but going from a 1.0dB preamp to a 0.5dB unit actually does show up. where it really matters is getting the preamp physically as close to the feed as possible. coax loss before the LNA kills you way more than 0.2dB of noise figure difference. i run a mast-mounted MGF1302 based preamp right at the feedpoint and that made a bigger difference than any other single change i made. also moon noise — yes sky noise varies but at 144MHz the moon itself isnt that noisy compared to HF galactic noise so you still have a decent system noise window to work with if youre pointed away from the galactic center

im kind of in the same boat as you, been thinking about this for a while. one thing i picked up at a club presentation is that the WSJT-X implementation of JT65B is really what opened EME up to smaller stations, like before digital modes even 4 yagis wasnt always enough to reliably complete contacts. now people are doing it with two yagis and legal limit more often than youd expect. still probably wont be easy but its not the impossible thing it used to be

the preamp thing i cant speak to from experience yet but the guy presenting said the mast mount vs shack mount thing is huge, something about even 3 feet of LMR-400 before the preamp adding noticeable noise. dunno if thats exactly right but it stuck with me