Jaycar’s LO1238 ferrite toroid is readily available in Australia at low cost and quite suits some HF RF projects.
The published data is near to useless, so a long time ago I measured some samples and created a table of complex permeability of the L15 material which I have used in many models over that time. It did concern me that measured µi was about 25% higher than spec, which is the limit of stated tolerance. Keep in mind that this is Chinese product with scant data published.
I have measured some samples purchased recently, and µi is closer to the specified 1000, so I intend using this new data in future projects.
Above is complex permeability calculated from s11 measurement of a single turn on the LO1238.