My gsm sniffer does not detect phones in standby mode.

[tulû]

Hi,I'm an undergraduate student in Turkey in Baskent University at Biomedical Engineering Department.
My term project is to design an cell phone dedector.
I found a circuit diagram in the internet about cell phone dedector which belongs to elektor-electronics.
This dedector which i set dedects the phones when there are
incoming/outgoing calls, sms sending/receiving ... but we can't dedect phones at standby mode.
Our purpose is to detect cell phones also in standby mode.
So, if it is possible i want to learn some technical info.
1)The electomagnetic field amplitude , the electrical field
amplitude ,power density of electromagnetic field in STANDBY MODE.
2)The above informations with in OUTGOING/CALLS and SMS RECEIVING/SENDING MODE.
If we know the difference amplitudes with standby and the other modes , we may go on our project.
By the way,the circuit which we used(to make remember), i uploaded its image : http://i29.tinypic.com/23w6zgw.jpg
And, the project which i found in the internet i added as attechment.
Thank you.
Tulû ÖZAN