so ive been doing SS phone and CW for the past few years as SO1R and doing ok, usually somewhere in the middle of the pack for my section. been reading a lot about SO2R lately and wondering if its actually worth getting into or if im just going to spend the whole contest fighting RF getting into my second radio instead of actually making contacts.

my current setup is a K3 and i have an old TS-570 sitting on the shelf that i could probably press into service. antennas are a 3 el yagi on 20 and a dipole that does 40 and 80. the feedlines run pretty close together in the shack which is probably going to be a problem. i know the filtering situation gets complicated fast, and BPFs arent cheap. anyway im just wondering if anyone has actually seen a meaningful rate improvement going SO2R or if most of the gain is coming from just being better at running and S&P in general

also curious if theres a point in the contest where SO2R really shines vs SO1R — like is it more useful early when rates are high or later when youre hunting for mults

SO2R is absolutely worth it but yeah the setup is not trivial, especially with antennas that close. the BPF situation is the first thing to solve — without good bandpass filters youre just going to have the second radio deafened by your TX on the first one and vice versa. 4O3A or Array Solutions filters are the go-to but theyre not cheap like you said. some guys build their own with decent results.

on the rate question, honestly SO2R pays off most in the mid-contest doldrums for me. when the rate on your run frequency is dropping off youre not just sitting there waiting, youre working a mult or grabbing a new call on the other radio. the really skilled SO2R ops can maintain a run on one radio while doing full S&P on the other which is kind of insane to watch but takes a long time to get comfortable with. starting out youll probably just use the second radio to grab mults during QSB or band changes and thats already a big improvement. K3 plus 570 is actually a pretty workable combo since you can slave the 570 off the K3 for some of the control stuff depending on how you set it up.

the antenna spacing thing is real, dont underestimate it. i tried SO2R with my antennas way too close one year and spent about two hours troubleshooting why my 40m audio sounded like garbage before i realized my 20m amp was just splattering all over it. ended up just running SO1R that contest and felt dumb about it. feedline routing matters too, keep them separated as much as you can physically manage.

one thing that helped me when i was first learning it — just use the second radio for receive only for a while. like tune around on it with headphones mixed in, dont even transmit on it, just get used to monitoring two bands mentally. its a weird cognitive load thing and it took me probably 3 or 4 contests before it started feeling natural instead of like i was just making mistakes on both radios at once