On my large 2.125 inch OD ferrite I wind coils on interchangeable forms for different purposes. Forms with an OD more than about 3 inches do not work as well.
I believe the TECSUN PL 360, 365 and GP-5/SSB all like pretty high uH to tune. I do get my Litz from your source, and also have the tuning caps he sells as Hi Q which would like a lower coil uH for MW. The interchangeable coil forms allow me to easily use the same ferrite. For outdoor temporary use, perhaps spraying with acrylic would help protect the Litz from moisture.
Recently I bought the portable version of the W6LVP broadband amplified loop which is interesting, mostly to set up outside on a remote hill top. It's only 2 feet in diameter, so reasonable to set up temporarily.
-FARMERIK
