JGR wrote: I would say the clip and wire you are using may benefit from a slight extension of about 15-20m, height above ground is the key factor to better reception.
Not on a portable radio. They overload very quickly.
If you look at sites such as the BDXC, a SWL club & maybe even THE only remaining British SWL club. Then you will see many successful SWL's only use a small portable & a short wire.