Broadband-Hamnet™ Forum :: Antennae
Board Index Latest Posts Welcome Guest   [Register]  [Login]
 Subject :Mounting Sector Panel with 2 degree electrical down tilt?.. 2014-08-02- 19:46:29 
AE6XE
Member
Joined: 2013-11-05- 00:09:51
Posts: 116
Location: 

This is a question/issue of interpreting the specs on a sector antenna.    In my case, for the Ubiquiti 19dB 120 deg 5G sector antenna.  Two statements in the specs:

1) 2 degree electrical down tilt
2) 4 degree electrical beamwidth  (should be in context to the vertical beam coverage area per the charts )

Is the electrical down tilt included in the 4 degree beamwidth or on top of this?  In other words, if I want the center of the signal-beam pointing down at 4 degrees, would we tilt the antenna down physically 2 degrees (to account for electrical 2 degree down tilt)?   Or do we point it down physically 4 degrees--and the 2 degree electrical down tilt represents the 4 degree bandwidth (2 degree down + 2 degrees up)?

http://dl.ubnt.com/datasheets/airmaxsector/airMAX_Sector_Antennas_DS.pdf

Anyone have any experience on this?

Joe AE6XE
IP Logged
 Subject :Re:Mounting Sector Panel with 2 degree electrical down tilt?.. 2014-08-02- 20:26:10 
KG6JEI
Member
Joined: 2013-12-02- 19:52:05
Posts: 516
Location: 

The downtilt and the beamwidth are indepednet of each other.

If it ships with 2 degree of down tilt and the antenna is vertically plumb than the center of the beam is at -2 degrees. With a 4 degree beamwidth this means it covers between 0 to -4 degrees with center again at -2.

So if you want to cover -2 to -6 you would need to shim it from the top to add an additional 2 degree of physical downtilt to give you a center at -4 ( -2 physical and + -2 electrical )

Note: Ubiquiti (like a lot of wifi antenna vendors) use -6dbm figures for beamwidth as compared to normal HAM antennas which use -3dbm. This data sheet calls out that it is -6dbm but some do not and it's easy to overlook as well. 
IP Logged
Note: Most posts submitted from iPhone
Page # 


Powered by ccBoard


SPONSORED AD: