Hello Philipp,
On Mon, 20 Jul 2009 18:39:47 +0200, "dexter" zero-kelvin@gmx.de wrote:
We have a Toy-Spectrum-Analyser here, so i have measured the output of our BS-11 when initalized with -f 123
http://www.root.runningserver.com/pub/openbsc_spektralanalyse.png
Not sure what you are measuring on peak one and two, but channel 123 should be 959.6 MHz, this is most certainly the third peak. There might be small signals (e.g. from the oscillator of the BS-11) on other frequencies, but they should be much smaller than the main signal.
I don't know what the specification for a BTS allows as level for emitting on other frequencies, so I can't give you any numbers how strong those other signals can be.
Best regards, Dieter
Hello Dieter,
There might be small signals (e.g. from the oscillator of the BS-11) on other frequencies, but they should be much smaller than the main signal.
I think that is the most plausible explaination. The antenna of the spectrum analyser was positioned very close to the BS11. That might be a reason why unwanted Signal comes out so strong.
besides: An expert told me that the grounding in our laboratory is not so good at all. That also might weak the shilding.
Thanks!
regards. Philipp
ok there are only downlink signals there since it s more than 935MHz. If I understand one of the pike 1&2 vanishes when you stop the BTS and the other one stays? Or is it the 3rd pike at 959.6 MHz who vanishes? I am not sure but I think you said the pike 1 disapeared and the pike 2 (weaker) staid... right? and the 3rd pike? The pike at 959.6 MHz corresponding to n = 123 is coming from the Tx0 for sure as Dieter said.
Can you say what you can see when you load the bs11 with bs11_config query? And which power did u setup? 30mW (default)?
Best regards, Eric
2009/7/20 Dieter Spaar spaar@mirider.augusta.de
Hello Philipp,
On Mon, 20 Jul 2009 18:39:47 +0200, "dexter" zero-kelvin@gmx.de wrote:
We have a Toy-Spectrum-Analyser here, so i have measured the output of our BS-11 when initalized with -f 123
http://www.root.runningserver.com/pub/openbsc_spektralanalyse.png
Not sure what you are measuring on peak one and two, but channel 123 should be 959.6 MHz, this is most certainly the third peak. There might be small signals (e.g. from the oscillator of the BS-11) on other frequencies, but they should be much smaller than the main signal.
I don't know what the specification for a BTS allows as level for emitting on other frequencies, so I can't give you any numbers how strong those other signals can be.
Best regards, Dieter -- Dieter Spaar, Germany spaar@mirider.augusta.de
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Dieter Spaar -
Eric Cathelinaud -
Philipp Fabian Benedikt Maier