On Fri, 10 Jul 2009 14:33:57 -0400, Michael Coslo
wrote:

Some sources are broadband, some are not.

It is quite often related to the pulse width and the pulse shape
coming from the source. Some shapes offer odd harmonics 3-5-7-9, some
even 2-4-6-8 (primary products, that is, as they all offer a full
complement of odd and even).

73's
Richard Clark, KB7QHC