ORIGINAL MESSAGE: On Wed, 18 Aug 2010 12:22:23 -0500, Rob Atkinson <ranchorobbo at gmail.com> wrote: > >For how long at 1500 w.? REPLY: As far as I know, that's for continuous operation, however the Eimac sheet for the 3-500Z does say that increasing airflow beyond the minimum will prolong tube life. Doesn't give any numbers. 73, Bill W6WRT