I usually run mine an hour when SWL-ing (maybe 2 if I'm lucky and have a dispensation from my XYL). Mine runs warm, but not too hot to put in my pocket if I had to. Cosmo probably has it right. If it's HOT, it's probably working too hard for some reason. My solid state 28 VDC PSU runs hotter. Jim Falls KG6FWT Eureka, CA