I read through the PL-310 manual. It says the external antenna jack works for FM (64-108mhz) and SW (<30 mhz).I still search...
I found: Tecsun PL-310ET
b) USB Power
c) Antenna Input
EDIT: I found a Manual: https://maplindownloads.s3-eu-west-1.amazonaws.com/A32UZ-10045.pdf
its right that the antenna imput is for <30 mhz?
or Tecsun PL-880
Tecsun PL-310ET -> EUR 35,95
Tecsun PL-880 -> EUR 182,21+ EUR 14,88 from US