What's a portfolio in terms of radio?

I know if you are an artiist you have a portfolio of your artwork. Here's the deal, My voice was recorded for a radio commercial and I was told I can add it to my portfolio. In the world of radio, what does that mean? what kind of portfolio does one have who is pursuing a career in radio? im a little confused and now i am thinking i should have a portfolio. thanks in advance

We call it an air-check. It's a recording of you directly off the air, with just the beginnings of the songs and commercials. PDs know the songs, they're just interested in you and how you sound and your technical abilities behind the board - so the middles are deleted. This would be called a "scoped air check" (teleSCOPED).

Some PDs will ask for an unscoped check, so they can get the feel of how you flow the station - or perhaps they're considering you for a format other than what's represented on the air-check.

In the day, we'd send tapes, then came cassettes, then CDs. Now you can email an audio file of yourself. Most jocks record every show, then pick the best bits from several, put them together and present to prospective employers.

You might even send a DVD demonstrating how you handle a personal appearance - but it's the air-check that will or won't get you hired.
-a guy named duh

training in that field

think of it as the same as that artist's portfolio of their artwork.

A portfolio in this case is selected vocal recordings such as commercials and on air recordings of you to give to prospective employers to listen to, to sample your abilities.