A bit more about spice models for RF transistors...

www.duncanamps.com has transistor models for some parts, as I noted
before. Specifically, there are several models for Motorola RF parts,
with the Moto numbers like MMBR931.

Some manufacturers provide spice models for current production parts,
if not for obsolete ones. For example, if you download the Philips RF
manual (as a PDF), you will find a page (current edition it's page 31)
of links to parts with spice models. The links take you to the Philips
page for that part; look for a link to the spice model on that page.

There seem to be some spice models on the ON semiconductor website, but
I don't know how to search them very efficiently. Maybe there's a
way...

Avago Technologies (used to be part of Agilent, used to be part of HP)
generally has a good set of S-parameters for various bias conditions
for their parts. Since the parts are generally intended for linear
amplifier service, that's reasonable.

It would be nice to have a place on the web to archive at least links
to models, if not (for copyright reasons) the models themselves.
Anyone know of such a site?