Re: [Openbts-discuss] USRP crosstalk

[Sylvain M. <24...@gm...>]

Hi,

(1) The stock RFX-type board does have inadequate uplink/downlink
> isolation for full duplex cellular, but this can be improved greatly
> by removing the C202 capacitor.
>

I can also confirm that even without this mod, it works fine with a single
RFX for desktop testing provided some code modification.
The performance will not be optimal but you can cover a big room without
issues.


> (2) With the C202 capacitor removed, it should be possible to run
> OpenBTS on a single RFX-type board without crosstalk creating a
> performance limitation.  The current OpenBTS transceiver does not
> support this, but that is probably due to suboptimal gain settings in
> the transceiver code.  It has not (yet) been a priority for Kestrel
> to correct this problem, but the OpenBTS transceiver really is open
> source and anyone who thinks it is really important to fix this has
> been welcome to do so all along.
>

I posted a patch to do that on the mailing list if anyone wants to try it.
You can find it in the list archives :

http://sourceforge.net/mailarchive/attachment.php?list_name=openbts-discuss&message_id=866320f70910151107w44c1395ew2213b6e73579b0e3%40mail.gmail.com&counter=1

I'll try and make the tranceiver configurable to support both config and/or
support dbsrx as a RX board as well.
It should even be possible to 'remerge' back 52M and 64M Tranceivers into a
single code base with just an init test or #if #endif

    Sylvain