Moved tubes to a window, ~ 3x counts.

Using some of my days off, I moved my counter to a window (still inside), hence about 3 times increasing in counts. Moving it outside I leave for another project.

P.S. Took me several attempts to actually post it here - submit was erroring with:

Connection closed by remote server

You tried to access the address http://radmon.org/index.php/kunena, which is currently unavailable.

while everything else, like previewing, worked fine.

That's quite a big jump. It's very hot outside. Have you walked around in your area carrying a geiger counter? Is there an open cut uranium mine near by?

It appears I got bitten by the same USB power stability bug. I tried to attach an external 5V battery and the elevated readings have disappeared. Looks like it's not only sensitive to the USB power stability, but also to the length of the USB cable. A short cable got my normal numbers back.

I deleted the elevated readings, thanks to the RadMon program.

That's good news.
A long usb cable can suffer from voltage drop as well as "noise". Noise has been a problem for me at a remote solar powered monitoring station I operate, that uses a power inverter. I needed to spend 3 times more than anticipated in order to get power that was clean enough not to generate false counts....