Thank you for the information on the code. Here is a simulation of the 750nH filter:
It looks like a good filter for 30m and 40m. Input impedance showed 50 ohms on 30m and 40 ohms on 40m.
Sorry the image isn't bigger -- in linux the filter program only prints to either a printer or to "Microsoft XPS Document Printer" which I don't have going in linux so I have to do a screenshot.