Teardown of a Ericsson radio base station, the RBS6000 system

[Mads Barnkob]

All technical details and high resolution pictures: http://kaizerpowerelectronics.dk/teardown/ericsson-radio-base-station-rbs6000-teardown/

The RBS6000 is an indoor Radio Base Station with one to four carriers and one to  six sectors at 20/40 Watt RF output power per carrier.

[Da_Stier]

Since I needed some S21 measurement for generating a .S2P file for some testing, I dug out a RBS6000 radio unit I have.
I measured the S21 characteristic of the TX output filter.



As expected, the center frequency lies right at 750MHz.
The -3dB bandwith of the filter is around 16MHz, which gives the filter a Q factor of over 46, wich I found quite amazing.



Hope this is interesting to some of you, even though this topic is quite old.

[Da_Stier]

Since I measured the TX Filter of the RBS6000 side, I got curious how the RX side of the filter would look like.
So I got myself some SMP to SMA pigtails and measured the RX side as well.

The results were quite interesting, not because of the filter caractaristics (they were quite obvious) but because how perfectly matched the two channels were.





Note how the two plots of the two RX channels are basically identical except the noise floor.
I didn't even have to move the cursors at all, they just matched.
I find that quite amazing and am wondering how much time is invested in tuning each one of these filters up to spec.


Greetings
Da_Stier