so ive been licensed for about 6 years now and done a fair amount of HF work, some 2m weak signal stuff with FT8 and i keep seeing EME contacts come up on the clusters and it just looks incredible to me. the idea of bouncing a signal off the moon and actually having someone hear it on the other side of the earth is just... i dont know, its one of those things that sounds impossible even when you understand the physics.

anyway i started reading into it more seriously and im getting a little overwhelmed with the equipment side of things. i know youre fighting maybe 250-260dB of path loss which is brutal, and that you basically need serious antenna gain to make up for it. ive been looking at 2m EME setups mostly since thats what seems most accessible, and i see guys running 4x yagi arrays or even dish setups. my backyard situation is... ok, i have maybe 50x60 feet to work with so a big dish is probably out but i could maybe do a 2x2 or 4 yagi setup if i built them myself.

what are the realistic minimum specs to actually make a contact these days? i know JT65 changed things a lot compared to the old CW only days but im not sure how much antenna i really need versus how good my preamp and feedline situation needs to be. any practical experience from people actually doing this would be really helpful, ive been going back and forth on this for months

the JT65B mode really did open things up for smaller stations, thats not hype. back when i started doing EME in the late 90s you pretty much needed a big array or forget it, and even then CW was marginal for a lot of contacts. now you can realistically work a decent number of stations with a single long yagi if the other end has a big setup, but you're going to be QRV as a small station and you have to manage expectations accordingly.

for 2m specifically, if youre going 2x2 yagi youre probably looking at around 14-15 dBd of gain depending on the yagis, which gets you in the game but youll mostly be working stations with large arrays or dishes on the other end. a 4x4 setup changes things considerably. the preamp situation is honestly just as important as the antenna though, you really want the lowest noise figure you can get right at the feedpoint, like 0.3-0.5dB NF ideally, and the coax run from there to the shack needs to be as short as possible or youre throwing away everything the preamp gives you. a lot of guys run the preamp at the antenna and use a sequencer to protect it during transmit, if you havent dealt with sequencers before thats something to learn early.

moon tracking is the other thing people underestimate. you need a way to aim the antenna at the moon with some accuracy and keep it there as the moon moves, which depending on your antenna design means either a rotator setup with an Az-El controller or if youre doing a fixed array, youre just watching for moon windows where it naturally comes into your pattern. either way worth sorting out before you commit to a specific antenna design.

just to add something that tripped me up when i first started - the polarization thing on 2m EME is a real issue and kind of annoying to deal with. Faraday rotation means the polarity of your signal is constantly shifting as it goes up and bounces back down, so if you and the other station are both running fixed linear polarization you can hit a null and basically disappear on each other even with good signal otherwise. some guys use circular polarization to get around this, others just live with the fading and work around it. its one of those things nobody really warns you about until youve had a contact just fall apart for no obvious reason.

also the EME2 software and WSJT-X with JT65B are kind of the de facto tools now, worth getting familiar with them on regular 2m weak signal work first so youre not learning the software at the same time youre trying to figure out your first moonbounce contact. the timing accuracy matters a lot more than people expect coming from regular FT8 use.