[Elecraft] Upper limits of KPA500?

[Andy Durbin]

When considering the upper temperature limit of a KPA500 I think it is important to know if, for the planned operating condition, the temperature limits at a value that the owner is willing to accept.  In other words,  does the fan produce sufficient airflow for the temperature to reach its maximum before thermal protection kicks in.  If it does, what is that limiting temperature and is it acceptable?

I have not tested any higher than 70 deg C and don't have any plans to do so.   I don't want to operate there because the fan noise is intolerable.  If I felt the need to operate in that region I think I would duct a much larger fan/blower to the rear chassis fan opening.

Data from one of my test runs shows the front left heat sink fin was only at 47 deg C when the finals peaked at 70 deg C.  The heat sink temperature continued to rise after TX stopped and peaked at 48 deg C.   This suggests to me that the thermal path between the finals and the heat sink could be improved but I have no expertise in this field.

73,
Andy, k3wyc