so ive been running my 7300 stock for about two years now and honestly its been fine but i kept reading about people swapping in the Collins mechanical filters on older rigs and started wondering if there was anything comparable worth doing to a modern SDR based radio like this. ended up going down a rabbit hole and found a few threads about tweaking the DSP filter settings and also some people doing hardware mods to the front end for better IMD performance.

what i actually ended up doing was the front end mod where you bypass part of the stock input filtering and add a low noise preamp stage. took me a weekend and honestly the difference on 40m in the evening is noticeable. the noise floor dropped maybe 3-4 dB by my measurement, might be confirmation bias but i dont think so. also reflashed the firmware to an older version someone recommended because apparently the newer ones have some AGC behavior that people dont love.

anyone else been messing with the 7300 hardware or is everyone just leaving them stock and using the DSP? curious what actual improvements people have gotten vs just tweaking software settings

yeah the front end on the 7300 is decent but it definitely has headroom issues when youve got a big signal nearby. i did something similar but went a different direction — added a bandpass filter array on a relay board before the antenna input, switched by band. pain to build but the IMD situation on 40 and 80 is way better now especially during contest weekends when everyones running legal limit a few kHz away.

didnt touch the firmware, been on whatever shipped with mine for over a year and havent had issues with the AGC people complain about. though i mostly do CW so maybe the SSB AGC weirdness doesnt affect me as much. the DSP filter in that radio is genuinely good if you set it right but it cant fix a garbage signal coming in, garbage in garbage out as they say.

i left mine stock and probably always will tbh. voided warranty stuff makes me nervous and im not confident enough in my soldering to poke around inside a radio i paid that much for. but curious what preamp you used, did you build it yourself or buy a module? ive seen some cheap LNA boards on ebay that people use for SDR dongles and always wondered if those were any good for actual use