cpt-120 temperature

I have a CPT-120 interfaced to a A128. The temperature has always varied widely and ranged from 5-20 degrees F over the actual temperature. It fluctuates over 10 degrees in a matter of minutes. Today it hit over 100 degrees F so I decided to write this post.

Downvision and chirp work great and give nice images.

What's wrong here?

Thanks