Using two antennas in a single RRU

[dacoder]

Is it possible to use 2 antennas for a single RRU? If i connect main port of one antenna to Tx/Rx port of RRU and the main port of 2nd antenna to the Rx port of the same RRU, will there be any problem? Only one port of each antenna is used and the remaining is left unused.

What i want to do is to align two antennas to different direction so as to increase the coverage of micro BTS.
RRU to be used is Huawei SRRU for 3G 2100Mhz

Thanks

[pathloss]

As you did NOT mention a lot about the HW, let me suppose your using two X-Pol antennas that face in two opposite directions, in order to increase coverage area.

- That you suggest would not boost your coverage are, as only one antenna is transmitting and receiving, while the other in opposite direction is only receiving. This is a no-go!
- What you can do. Is to split your signal (50%/50%) on the Tx/Rx Port with a 3dB Splitter and to do same on your RX Port on the RRU. In that case you'll use two ports per antenna. Or, you could even think about putting a load on your Rx Port. In that case you really only use one port per antenna.


38458
Credit to DANCESTORM for the Picture.

[dacoder]

As you did NOT mention a lot about the HW, let me suppose your using two X-Pol antennas that face in two opposite directions, in order to increase coverage area.

- That you suggest would not boost your coverage are, as only one antenna is transmitting and receiving, while the other in opposite direction is only receiving. This is a no-go!
- What you can do. Is to split your signal (50%/50%) on the Tx/Rx Port with a 3dB Splitter and to do same on your RX Port on the RRU. In that case you'll use two ports per antenna. Or, you could even think about putting a load on your Rx Port. In that case you really only use one port per antenna.


38458
Credit to DANCESTORM for the Picture.
yes, i'm using two x-pol antennas. Thanks for the explanation. One question though: in this scenario with splitter the total tx power is halved per antenna right? if so coverage is reduced as well?

thanks

[pathloss]

Yes, indeed. Halve of the power goes to the first antenna and the other halve goes to the second one.
Well, compared to the scenario with only one antenna, you lose 3dB in that direction, but on the other side, you have now one more antenna that you may direct to another direction.

Guess the picture explains best.
38465

[dacoder]

thanks for the explanation. Did you make that pic yourself or is it from some doc? If it is, could you kindly share it with us?

thanks

[pathloss]

You are welcome.:D

Did a quick drawing in Word and screencaped it. So,no don't have a doc for this but a good link for you.

This Guy I know from Telecomhall does good stuff.
http://www.telecomhall.com/what-is-splitter-and-combiner.aspx