A couple suggestions. The gain of the antenna is going to be very nearly the same in the restricted bands as at the fundamental. So I would attenuate the fundamental until it didn't overload the analyzer, and make measurements in the restricted bands. I haven't crunched the numbers, but I think that the restricted bands will need to be 80 dB down from the fundamental. I think that is a feasible measurement. if the concern is unintentional radiation, then you can dummy load the antenna and just measure RE at 3 m. Dummy loading the antenna can be removal and replacement by a shielded, matched resistive load, or operating into absorber, especially if the antenna is not omni-directional but high gain.
---------- >From: [email protected] >To: [email protected] >Subject: FCC Testing 2.45 GHz Transmitter >Date: Tue, Sep 10, 2002, 8:07 AM > > > Consider a 1W frequency hopping, spread spectrum transmitter operating at > 2.45 GHz. The FCC released a Public Notice on acceptable test methods > (Filing and Measurement Guidelines for Frequency Hopping Spread Spectrum > Systems) where they "recommend" that the spurious radiated emissions in the > restricted bands are to be measured with a high pass filter. There is a > restricted band at 2483.5-2500 MHz. Given a 1W transmitter and a spurious > limit of 500 uV/m at 3 m, it would seem that I need a very sharp high pass > filter or a very good notch filter to measure in that band. Is this > feasible? > > It would also seem that a notch filter or low pass filter is required for > measuring spurious emissions in the restricted bands below 2.45 GHz. There > is a restricted band at 2310-2390 MHz. Again, is a filter feasible? > > I am aware of semi-custom filter suppliers, but are there any off-the-shelf > filters available? > > Richard Woods > Sensormatic Electronics > Tyco International > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > [email protected] > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Ron Pickard: [email protected] > Dave Heald: [email protected] > > For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > http://ieeepstc.mindcruiser.com/ > Click on "browse" and then "emc-pstc mailing list" > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
