Many thanks to SWLing Post contributor, Rolf Snijder, who writes:
I did a modification today on the Tecsun PL-680 [which allows for an] external antenna on LW and MW.
The internal ferriet is also working, but on my active loop, MW and LW is now working !
So far away stations I can now receive on this portable radio.
It is only a560 pF capacitor added!
It works on LW and MW now with this mod.
FM is less now I think, maybe I will put it on a switch so I can turn it off.
And now also the ferrite is still working, so I hope to find a solution for that.
Many thanks for sharing your modification and photos, Rolf! Check out Rolf’s other PL-680 mod by clicking here.