so ive been running my IC-706MKIIG for about three years now and honestly it's been a solid radio but the stock SSB filter always felt a little mushy to me, like there was always just a bit more adjacent channel bleed than i wanted especially during contests or when the 40m band is packed. anyway finally pulled the trigger on installing a Collins mechanical filter, the 2.1kHz one, took me most of a saturday afternoon which is longer than it should have been because i had to chase down a cold solder joint i made like an idiot.

difference is actually pretty noticeable? like not night and day but when youre sitting there trying to pull a weak station out from under a strong one 5kHz away it really helps. audio sounds tighter too, less of that fuzzy edge on voices. not sure if its placebo but i feel like i can copy callsigns better now. anyone else done this or similar filter swaps on their rigs? curious if the 1.8kHz version would've been a better call for CW focused stuff even though i mostly do SSB

yeah the collins filters make a real difference on those older icoms, done the same thing on a 735 years back. the 2.1 is a good middle ground for SSB honestly, i wouldnt go narrower unless youre really CW only because it starts to sound kinda boxy on voice. one thing i'll mention — if you havent already, look at whether your IF shift is calibrated right after the swap. sometimes the center freq is slightly off from the stock filter and you end up wondering why strong signals still sound a bit off even with the better filter in there. easy to tweak in the menu if i remember right on the 706.

I've been thinking about doing something similar with my 7300 but obviously thats a different situation with the SDR architecture, you can't just drop a mechanical filter in there. software DSP does a lot but i still feel like theres something about a real hardware filter that just... works differently? hard to explain. anyway good to hear the mod paid off, cold solder joints are the worst, i spent two hours once chasing one on a completely different project and wanted to throw the whole thing out the window