Behind The Scenes - 700Mhz LTE hardware

Does alpha, beta, gamma, sectors have any significant meaning? I have seen some towers (not necessarily LTE) where one sector has an extra antenna vs the other two.

 

I thought US operators used more US made antennas, like Andrew? Kathrein is a German manufacturer, probably the biggest cellular antenna company in the world, they make great antennas. A Kathrein connected to an Ericsson RBS6000 with a FO connection, it doesn't get much better than that

It's just a naming convention to identify each sector. You can also say Sector 1, 2, 3, or Sector A, B, C.

For example: Sector 1 is pointing at 0°, the antenna has a -4° mechanical down-tilt, Sector 2 is pointing at 90° and has +6° mechanical up-tilt, and Sector 3 is pointing 240° and has a mechanical tilt of 0°. The output power of the RBS could also be different for each sector. Also neighbor cell definitions are set per sector, so neighbor cells for Sector 1 will be different for Sector 2.

Antenna installation crews often make the mistake of swapping feeder cables to the wrong antenna (eg. cable from RBS sector 1 is connected by accident to antenna Sector 2) and then this causes alot of dropped calls because of wrong neighbor relations, as well as interference if tilts are different.



The installation crew marked this:

AZM: 240 = Azimuth 240°
RC: 350 = I don't know what they mean by that?
MDT:0° = Mechanical Down Tilt is zero degrees
EDT: 0° = Electrical Down Tilt is zero degrees.

Antennas can be up/down-tilted mechanically by adjusting physical installation brackets. Antennas can also be tilted electrically by adjusting the phase of transmission (read more here). The patters are different for electrical and mechanical tilts. Electrical tilt is easier to adjust as it can be done remotely.