Not sure if this data might be useful to others...
My current U2 is housed in a metal box.
The DDS can has stick on heatsink.
The internal PSU regulators generate a fair bit of heat and so does
the PA, so the internals of the box do get quite warm.
I experience no ill effects, and the PA at 9v and no heatsinks just
keeps on running at 100% duty cycle on QRSS.
From switch on (NO GPS) I might experience about a 1Hz drift as
observed on WSPR.
Within 20 mins everything is perfectly stable and doesn't wander
in the slightest. It's better than my FT817 or IC706's ;-)
My experience in the past though with excessive drift was caused
by even the *slightest* temeprature movement on the DDS can.
Exactly as per the instructions from Hans mentioned when the U2
was released.
Hope this helps.
73 de Andy
