Mathcad 6.0 PE for Mac computers is available from Mathsoft. All later versions of Mathcad ie. Use PgDn key instead. It is excellent idea to run FilterD under Mathcad Explorer. You can design all types of filters but no Cauer filters for free.
Disadvantage is only one.
You can not write down design worksheet into disk. Top of document Units Each number have a unit. If you incidentally erase eg. You can write W letter and press Ctrl-G combination of keys. If somebody will find my files useful it will be funny to me to obtain short e-mail with text I like Analog Filter Design with Mathcad.