FCDEV3B bring-up status

Mychaela Falconia mychaela.falconia at gmail.com
Sat Apr 29 05:22:09 UTC 2017

Hi Serg,

> Would like to share some experience trying to calibrate VCXO. I ran the
> manual process with CMU200 and everything went okay, just like Mychaela
> described. I got different numbers but within the same range and with
> similar trend.


> However an attempt to go against the live network did not
> work, the network was starting LUP and apparently could not decode bursts.

What do you mean by the network starting LUP?  The Location Update
procedure is initiated by the MS when it finds a good cell, not by the
network - the process starts with the MS sending a RACH to which the
network will reply with an Immediate Assignment.  Are you getting to
the point where the MS is sending out a RACH after having locked onto
the right cell in your area?  Does the RACH seem to be then ignored by
the network, leading you to the conclusion that the network is unable
to decode the bursts sent by the MS?  Or are you getting as far as the
dedicated channel establishment for the LUP, and then getting some
behavior that seems like bursts not being decoded correctly?

Do you have an rvinterf log that you can share?  (Remember, no mail
attachments on this list, please post a link instead.)

> So far I stopped any further attempts and will study CMU200 procedures how
> to setup proper BS simulation.

If you do this part, you will be ahead of me, as I haven't exercised
the CMU200's GSM signaling modes yet, only non-signaling.

> The unit I acquired seems to be in good working order and I have 10 MHz
> GPSDO connected to it as an external reference.

Just curious, is your GPSDO a Trimble Thunderbolt?  I used to be on
the time-nuts list, and the Thunderbolt was everyone's favorite GPSDO.

I don't have a GPSDO setup currently (I do have a Thunderbolt unit,
but no outdoor GPS antenna setup), so I'm running my CMU200 with its
internal timing reference.  But my unit does have the better of the
two OCXO options (called B12 IIRC), so I think it's probably good


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