Faulty flightaware orange ???

I have had my orange flightaware stick about a month now. It is conected to a good USB hub powered with 5 amp supply.
The fist week or so, all was good, but since then performance seems to drop off. If I reboot the pi my noise levels, signal levels and max range stay the same, but if I disconnect the USB hub from its power supply for 10 seconds, then all of the above increase as do my nmessages ands flights. Its performance seems to drop off over each day I leave it connected.
Is it faulty or do these orange sticks need disconnecting regularly?

First thing I’d do is to check all your connections to ensure they’re solid. I’m guessing you’re seeing noise creeping in at a loose antenna connection or something.

No, only antenna connection is at filter and to usb stick. Noise and signal deteriorate over 24hrs. I average a received distance of about 200 miles when I restart the USB stick 9 hours later it has dropped to about 160 miles. Peak signal level is -0.8 and within 24 hrs drops to about -3, noise is at -22 and drops to about -26. Seems as if the internal amp is losing gain over time??