Hi We sold a sma connector to the iMote2 board which was connected directly to the spectrum analyzer, through a good and short cable (I assume < 1dB att @ 2.4GHz).
I did not use a vector network analyzer to check the impedance... so the only thing I guess now is that we had to move one smd capacitor, which is pretty small, so perhaps it was a bit burned after sold again. Hence the output impedance could be a bit non-matched. I would not be surprised if the iMote is not giving 0 dBm, but some dB less... On Tue, Feb 21, 2012 at 4:45 PM, Xiaohui Liu <[email protected]> wrote: > Hi, > > This is what the datasheet says: > power vs dBm > 3 -25 > 7 -15 > 11 -10 > 15 -7 > 19 -5 > 24 -3 > 27 -1 > 31 0 > > Somehow your measurement of those power levels is 4-5 dBm lower than what > is shown above. > > Are you using an attenuator over the antenna or measuring the power some > distance away? I'm not familiar with spectrum analyzer, so I'm just giving > some naive guess here. > > > On Tue, Feb 21, 2012 at 7:52 AM, Sergio Valcarcel <[email protected]>wrote: > >> Hi, >> >> this is what I measured one and a half year ago using an iMote2 and a >> spectrum analyzer, I actually demodulated the signal so you can be sure >> that the values are quite accurate. >> However the weird thing is that the mote did not rise to 0dBm, but only >> to -4dBm. Sorry, I did not remember whether each column belongs to a >> different mote. Also, note that setting the value to 0 it gives the maximum >> power, but 1 stands for the least output power. >> >> 0 -4.1 >> 1 -51 >> 2 -46 >> 3 -29 -28.9 4 -22 -22.8 5 -22 -22.7 6 -22 -22.5 7 -19 -19.4 8 -16.5 >> -16.6 9 -16.5 -16.5 10 -16.5 -16.42 11 -15.5 -14.6 12 -13.8 -12.7 13 >> -13.7 -12.7 14 -13.7 -12.6 15 -12.4 -11.4 16 -11.1 -10 17 -10 -10 18 >> -10 -10 19 -9 -9 20 -8 -8 21 -8 -8 22 -8 -8 23 -7.2 -7.2 24 -6.5 >> -6.3 25 -6.5 -6.3 26 -6.3 -6.3 27 -5.7 -5.6 28 -5 -4.9 29 -5 -4.9 >> 30 -5 -4.9 31 -4.4 -4.3 >> I hope this helps! >> Cheers! >> Sergio >> >> On Tue, Feb 21, 2012 at 6:10 AM, Xiaohui Liu <[email protected]> wrote: >> >>> Hi everyone, >>> >>> Does anyone know what the output powers are at each power level from 0 >>> to 31 for CC2420? >>> The CC2420 datasheet only gives the output power for level 3, 7, 11, 15, >>> 19, 23, 27 and 31. However, the output power for other levels like 2 or 12 >>> are missing. I find some threads such as >>> 1<http://comments.gmane.org/gmane.os.tinyos.users/18536.>, >>> 2<http://mail.millennium.berkeley.edu/pipermail/tinyos-help/2009-March/039014.html> >>> and >>> 3<http://mail.millennium.berkeley.edu/pipermail/tinyos-help/2007-August/027345.html>, >>> asking similar question, but no definitive answers based on measurements >>> have been given. Please advise. Your help is truly appreciated. >>> >>> -- >>> -Xiaohui Liu >>> >>> _______________________________________________ >>> Tinyos-help mailing list >>> [email protected] >>> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help >>> >> >> > > > -- > -Xiaohui Liu >
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