What signal strength should I be getting if base is transmitting thru a thermal pane window to the Tempest sensor 25 feet away.
I currently get -52 on the hub and -78 on the sensor.
Battery is at 2.8 volts and charging.
Both values are good.
RSSi is in db and is a negative scale, the closer to zero the best. You can go down to -75db without issues, over -85 you can have some drop outs but backfilling will mostly ‘hide’ this. Lower than -90 is critical and you will have drop outs or disconnects.
Agai your numbers are very good and nothing to worry about 
I had to move it to this location because where I really wanted it I had -114 and worked ok for 2 days then it started to loose connection.
I just wanted to be sure this is normal since it’s advertised good up to 1000 feet
you just have a part of the sentence 
connection up to 300 meters (1000 ft+) unobstructed, in clear line of sight.