Does the XR9 really have a built in filter?

[VistaVox]

We have been implementing 900 mhz network. The equipment used are mikrotik RB433AH router boards, XR9 radios, and 12dbi omni antennas. We have most of the high elevation areas in our town, the last couple of 900 AP's we have put up, have had some major interference issues. The broadcast can be seen from great distances, but trying to get data back to the AP is where the connection issues come in. When we connect from very close (at the base of the tower) we can see the broadcast at say -55, when we connect and check registartion transmit signal strentgh is only about -88. I have heard that the XR9's have built in filters, ? with the waverider AP's we have filters designed for each frequency. They don't seem to have any interference problems. I have found these online and am going to try them. http://www.hyperlinktech.com/item.aspx?id=858 does anyone have any suggestions, thanks

[jcremin]

What does the AP side XR9 report for a noise floor?

[UBNT-Robert]

Hello,

Yes, XR9 does have fairly aggressive filtering of the 902-928MHz ISM band. However, in our experience and depending on the area, there can be strong pager signals at around 930MHz (and 900MHz; not as common) which are difficult to filter out without some kind of cavity filter with steep roll-off and rejection at 930MHz.

We have a CF-912 Filter that does this and is available through our resellers.


Robert

[VistaVox]

Thanks for the replies guys, we have since found one of our problems. We had a brand new, bad omni that was leaking RF. But, we will be using the cavity filters for added isolation.

[bobbyc]

I have two sites where a CF912 filter made a huge difference in filtering out the upper 900 noise with XR9s. The built in filter can only do so much.

But Robert, the cavity filters don't show up on your website anymore; and you can't find the CF912 or CF917 anywhere online.

Thanks,
Bob C

[WHT]

http://www.hyperlinktech.com/item.aspx?id=857

900 MHz Ultra High Q 4-Pole Indoor Bandpass Filter, Full Band

The HyperLink 900 MHz 4-Pole Ultra-High Q full band filter is designed for full band applications. By reducing interference outside the 915 MHz band such as from cellular and paging signals, improved performance in noisy environments can be achieved. The BPF900 series filters are ideal for use with 902-928 MHz ISM band applications as well as 900 MHz RFID applications.