If you're monitoring an 800 MHz system, weather and wind-blown foliage can impact the received signal. Other conditions can also affect the signal strength, but may not change as frequently as the weather. You say that the analyze function shows an excellent quality level. That functions displays the quality of the digital decoding. With a simulcast system, you could have a lower signal level with a high decode quality, and you'd be in good shape. The only way to know for sure if you've damaged your antenna is to try another antenna to see if there's any change in signal levels.