so ive been going back and forth on this for a while now. i have an IC-7300 thats been sitting pretty much stock since i got it two years ago and ive been reading about the MARS/CAP mod to open up the TX range a bit. i know you just move a couple of jumpers inside and thats basically it but i guess my question is more about whether people have noticed any actual performance difference or if its just kind of a nice-to-have thing you do and then never use.

i'm mostly an HF guy, work some 40 and 20m, occasionally play around on 17. not doing any MARS or EMCOMM work right now but i kind of like the idea of having the flexibility if i ever need it. also i heard some people do this just to allow slight out-of-band tuning which can matter when you're near a band edge and the rig starts limiting power. is that actually a thing or am i misremembering something i read on eham.

and yes i know it voids the warranty, mine is way out of warranty anyway so thats not a concern. just want to hear from people who've actually done it rather than the usual "consult your local regulations" type responses

yeah i did this on mine maybe 8 months ago, took like 20 minutes including the time i spent convincing myself i wasnt going to break anything. the jumper is pretty accessible once you have the top cover off, icom actually made it pretty straightforward. you do have to do the menu reset thing after or it wont take effect, i forgot that the first time and thought i'd done something wrong.

as for whether its worth it — honestly for day to day HF operating probably not a huge deal. but you're right about the band edge thing, there's a real difference when you're sitting at like 14.350 and the rig is already pulling back power. with the mod it doesnt do that, which is nice if you're contesting or just working the edges a lot. i also do some utility monitoring and having a bit more flexibility on the TX side is just a comfort thing even if i never actually transmit out of band. just feels less restricted if that makes sense.

the band edge power rolloff thing is definitely real, not just something you read on eham. icom builds in that protection deliberately and the mod bypasses it. whether that matters depends on what you're doing i guess. for casual ragchewing probably irrelevant but i noticed it immediately when i was doing a contest and kept parking near 14.350.

one thing i'll add — after you do the mod some people notice the ALC behavior changes slightly in certain modes, nothing dramatic but worth knowing. and make sure you're actually on the right jumper if you go in there, there's a diagram floating around on the radioreference forums that's way better than the one in the service manual. the service manual one is technically correct but the photo quality is garbage.