Did you shield the mote? A metal shield attached to the mote's ground would be good, one attached to an earth ground would be better. This would reduce much of the "Without antenna" transmission the mote generates and make sure you are measuring the antenna only.
Every part, the connector, leads, and traces, after the radio is part of the antenna. -Ben On Fri, May 25, 2007 2:55 am, Munaretto, Daniele said: > Thank you very much! > Cheers > Daniele > -----Original Message----- > From: Robert Szewczyk [mailto:[EMAIL PROTECTED] > Sent: Thursday, May 24, 2007 8:00 PM > To: Munaretto, Daniele > Cc: [email protected] > Subject: Re: [Tinyos-help] micaz,gain & tx power with eternal antennas > > Danielle, > > 6 dBi antenna means in the main lobe, it will provide 6 dB gain over > an idealized isotropic antenna. The directional antenna transmitting > at -7 dB should give you performance comparable to a 0dBi antenna > transmitting at maximum power (at least in free space). > > Additional comments: > - a receiving antenna also provides gain along its main beam, so with > two 6dBi antennas pointed at each other you should expect signal > that's 12 dB stronger than that transmitted between a pair of nodes > with 0dBi antennas. > - typically, the larger the gain along the main lobe the smaller the > secondary lobes. > > > Cheers, > > Rob > > On 5/24/07, Munaretto, Daniele <[EMAIL PROTECTED]> wrote: >> >> >> >> >> Dear all, >> >> >> >> I did other tests and removing the original antennas from the micaz motes >> reduces the tx range. >> >> Now, I have a new question. >> >> >> >> If I fix to 15 the RFpower (CC2420), it means -7dBm, and the attached >> directional antenna has a gain of 6 dBi, how should I consider the real TX >> power of my mote? I have to sum up, consider only one of them, ..? I >> really >> don't know and I cannot find documentation. For me it's important for >> understanding if I can reduce and how much I can reduce the secondary >> lobes >> of my external directional antennas. >> >> >> >> Please, if any one of you has experience, could you help me? >> >> >> >> Cheers >> >> Daniele >> >> >> >> >> >> >> >> >> >> >> Daniele Munaretto >> >> Researcher -- The difference between the right word and the almost right word is really a large matter- it's the difference between a lightning bug and the lightning. -Twain _______________________________________________ Tinyos-help mailing list [email protected] https://mail.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
