so ive been reading about EME for probably two years now and i keep putting it off because the antenna requirements always scared me off. running about 500w on 2m right now with a pretty decent yagi setup for terrestrial stuff but i know thats nowhere near enough for moonbounce. been looking at the WSJT-X digital modes since i know JT65 is basically what everyone uses for this now and that helps a lot with the weak signal side of things but im still fuzzy on whether a single long yagi is ever going to cut it or if i absolutely need to go array.

the path loss numbers are just absurd when you actually sit down and calculate them, like 250+ dB round trip is not something i was prepared for when i first looked into this. i get that the moon is a terrible reflector too, only bouncing back like 7% of what hits it or something like that. so between the path loss and the inefficiency of the moon itself you need a ton of EIRP and a really low noise figure on receive.

current setup is a 17 element yagi at about 40 feet, preamp is a down east microwave unit right at the feedpoint which i think is around 0.5 dB NF, and the 500w solid state amp. is there any realistic path to making contacts with this or am i just kidding myself until i build a 4-bay array

honestly you're not as far off as you think, at least for initial QSOs with the big gun stations. JT65B on 2m EME is doing a lot of the heavy lifting these days and there are stations running 4 x 19el arrays with a kilowatt that are actively hunting for small stations to work. your NF sounds solid which is actually half the battle on receive, and 500w is workable if your antenna has decent gain.

the 17el yagi, whats the boom length and who made it? thats going to matter a lot. something like an M2 or a home brew based on DL6WU dimensions is going to be very different from a cheap commercial antenna with sloppy element spacing. if you can get your ERP up to maybe 300-400w equivalent into a antenna with 17-18 dBd youll show up in someones JT65 decode, especially during the big EME contests like the ARRL EME contest in the fall. i worked my first moon contact with a single yagi setup not too different from yours, took a while to find the right opportunity but it happened.

the main thing id say is get on the logger at df2zc.de and start watching who is calling CQ on 144.120, youll get a sense pretty quickly of whos hearable from your location and which big stations to aim at first.

yeah the path loss thing is kind of a gut punch the first time you really look at it. i went through the same thing maybe 3 years back. what i ended up doing was building a 2x9el cross yagi setup first just to dip my toes in and i did actually get a handful of contacts that way, all JT65B, all with stations running serious iron on the other end but still it counts.

your preamp placement sounds right, feedpoint mounting is the way to go, every foot of coax before the LNA is just adding noise you cant get back. one thing people dont always mention is polarization, if youre running a single linearly polarized yagi youre going to lose contacts to faraday rotation which is constantly shifting the polarization of the signal off the moon. some guys just live with it and wait for the rotation to be favorable, others go to circular or cross-pol. not a dealbreaker at your stage but worth knowing why contacts sometimes just fall apart for no obvious reason.