I tend to avoid silver radios for this reason.

There's nothing in the manual suggesting that the scan sensitivity can be adjusted. I wasn't aware that the PL-330 had such a feature either. The only radio I know with an adjustable ATS scan threshold is the Qodosen DX-286/SR-286. The PL-660 is a great radio, but it's ATS threshold is far too low, storing lots of just plain noise until the memory fills up.

Yes.

if you're actually into shortwave the Tecsun PL-660/680 are far better radios with pure analogue design and the best sounding SSB audio compared to dsp radios, SSB on commercial bands has big advantages and is a great tool against noise or strong signals near a station you want to listen to and a great tool against fading signals and you get the joy of tuning around the bands with a proper VFO instead of just a scan up or down option. The PL-660/680 also have external antenna input so you can connect a proper antenna like the Bonito MA-305 FT whip which offers absolutely amazing performance for it's size provided you have somewhere to mount it outside preferably somewhere away from houses and apartments as you can. Ground your coax to keep static from entering the radio.

LiJiANi have a few small radios on Amazon. It's quite a capable little radio and reasonably priced. They're available in Amazon US and from AliExpress. I have written a good bit about the radio on BlogOrDie.com and I will be comparing it later in the month with the incoming HanRongDa HRD-757.

I have the KA900 and it is one awesome radio!! The FM is pretty good, AM and shortwave are just ok. The real strength is in the NOAA , the SD card and it is a magnificent BlueTooth speaker. I have hundreds of hours of old radio shows on the SD card for when the power goes out.