Yes the zbitx runs too hot. ?The linear regulator will make the back plate hot even while sitting idle but still reasonable. ?72c is not too hot for the zero as it’s under the thermal throttle threshold which I cannot remember is maybe 85c? ?On transmit though I haven’t checked but the radiant heat from the finals and back plate into the zero may push it into thermal throttle. ?It really needs a genuine heatsink on the back which I will be working on soon.

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Ryan

KK6dzb

Hi,

just tested my zbitx with 9v ps and 2 w output and 20% rate in wspr.
Backplate got extremly hot that I was able to hold it in hands for less than 5 seconds, what means over70 degree c out of my personal experience.

Had to lower output to 1 w and 10% rate to give enough cooling down time. Will check with a temp probe later.
Best solution would be to change the backplate to a real heat sink I guess.

'73