There really is only one thing I would want added to the KX-3 . . .
I am sitting in the shack in the wee hours of the morning using a fully charged laptop, cell phone hot spot and solar charged 12v battery for my KX-3. (The power has been turned off because of massive greed, neglect and incompetent management on the part of PG&E. Our infrastructure is just like our government – falling apart). Make America Great Again (my ass).
OK – back to something that does work – the KX-3. With no electricity, the noise level is very low. Only 1 S unit lower than with electricity, but there is a caveat here – at certain hours of the night – someone turns on something that basically makes a grinding noise that wipes out 40M. Its only during the evening and when people would watch TV. It does go away when people go to bed – and I get up in the middle of the night.
If there were a receive port on the KX-3, and if I could switch to a diversity mode of receive on the KX-3, then I could null out the noise with a magnetic loop antenna. In fact – I could get away with a simple passive home made RX sensing antenna and point it at my neighbors noise source.
And yes – I know DX Engineering makes this: https://www.dxengineering.com/search/product-line/dx-engineering-rtr-2-modular-receive-transmit-interfaces?autoview=SKU&keyword=rx%20port&sortby=BestKeywordMatch&sortorder=Ascending
But I would want the RX port built in to the rig – not external boxes that aren’t portable.
That’s it – that is all I would want in a KX-4 – no fish finder scope that would eat my battery, I can’t think of anything else.