How Antennas Change Over Time

Antennas and base station sites, they can be seen everywhere these days but it's pretty difficult to see how they change over time. When I recently came home and looked out the window I could at first not  exactly say what it was but I had the impression that something had changed at the antenna site on the building at the opposite side of the street. But I couldn't quite figure out what was different. Then I remembered that I took a picture two years go so it was easy to compare.

And here's the result: The left part of the image (click to enlarge) shows how the antenna construction looks today and the right part shows how it looked like two years ago. Before the configuration was changed there were three antennas covering each sector. One antenna was installed on top and two antennas were mounted below closely side by side. Today, there's only a single antenna casing with at least two antennas inside as can be deducted by the number of cables at the bottom of the antenna casing. Furthermore, a second microwave antenna has been installed on the main mast below the one already used two years ago.

Quite a significant change and I can only speculate why it was done!? I am pretty sure the top antenna belonged to a different network operator than the lower antenna. So does this absence mean that this operator no longer uses the tower? It's likely as I am not aware of any antenna sharing deals between network operators. And how could the lower antennas have been changed at the same time as the upper antenna of presumably a different company was removed? Coincidence? Cooperation?

Questions over questions. But one thing is for sure: I don't remember my surroundings in as much detail as I always thought as otherwise I would have immediately noticed the missing top antenna instead of having to compare today's state with that of two years ago. That is interesting as well.

P.S.: Note that the sky is grey on both pictures. I'll let you draw your own conclusions…