You could temporarily move the antenna. Run a temp cable from the CMM4 out to the parking lot or some thing and see if the problem goes away.
From: Eric Muehleisen Sent: Friday, December 1, 2017 7:51 AM To: af@afmug.com Subject: [AFMUG] GPS visible vs tracked We have a site where we see unusual GPS issues. I've been graphing the CMM4 and it visually sees between 10-15 satellites consistently. However, tracked satellites will go from 8-10 and drop to zero for hours at a time, then fully recover. This happens randomly a few times a week. It's gotten worse over the past month. See attached. If you notice, there is an FM antenna right next to our equipment. We have occasional ethernet related issue as well. This tends to get worse when it rains, but overall hasn't been a major issue. Could our GPS issues be related to the FM station? We plan on moving the GPS antenna to another location next week. Has anyone seen anything like this before?