BS11 power problem

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Sergey V. Efimoff risky at mail.ru
Fri Dec 3 12:01:45 UTC 2010


Hello Harald,

On Dec 3, 2010, at 2:22 AM, Harald Welte wrote:

> On Thu, Dec 02, 2010 at 09:58:23PM +0300, Sergey V. Efimoff wrote:
> 
>> But right after the very first GSM call the receive level quickly jumps down
>> to -70 or even -80 dBm, this value corresponds to 30mW of output power. BTS
>> station still works and output power is still shown as 2W.
> 
> In case you are running a multi-TRX BTS: is this the received power level on
> the TCH of the call or on the BCCH ?  If downlink power control is active, the
> BTS will not send more power than needed on a dedicated channel...

The receive level is shown for BCCH.

>> This effect had been discovered with only one of my BTS stations, while other
>> stations work well.  Does it mean that it's a hardware problem? Has anyone
>> discovered this problem earlier?
> Are the other BTS's configured exactly the same way?  As explained, the
> difference single-trx / dual-trx and downlink power control might explain it.

Yes, other stations are configured exactly the same way. 

> otherwise, if configuration of bs-11, openbsc and the bs11 firmware is
> identical, it might well be a hardware issue.  But I don't get why it would
> be related to the first call or not...

I am confused. I did not observe this effect earlier on this station. And I do not
observe it on other stations. I also don't know why this effect appears after
the first call. It really seems to be a hardware problem.

Best Regards,
Sergey.





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