I occasionally drive by one of the old Bell System microwave radio relay towers here in Michigan and always wondered if it was still active. Does anyone know if any of the original microwave relays are still being used (i.e. the original 4GHz systems)?

I found that the transmitter still has an active FCC license, so that is what led me to believe they might still be in use. The particular link that still has active call signs runs from Traverse City, Mich to Perkins, Michigan. For reference, the Allenville tower that I've been past has the call sign WHR249. If they are still active, are they just used for backup, or do they regularly carry calls? What is their capacity?

With all the knowledgeable and experienced folks on this site, I'm sure someone will know!

-Nelson