I think that some of the responses to this question were based on different assumptions than others.
Some responders claimed that if a high noise figure spectrum analyzer was used, then a preselector would be necessary to give adequate sensitivity. Implicit in this response is the idea of a built-in preamplifier along with the preselector filter. Other responders talked only about the rf filter function. To me a preselector is only a filter centered on the spectrum analyzer tuned frequency, with a bandpass somewhat wider than the widest SA intermediate filter. I don't feel that kind of instrument is helpful in a shielded anechoic chamber (SAC) UNLESS the EUT is an intentional transmitter and you need to measure low-level unintentional emissions in the presence of the stronger transmission. If you do need extra sensitivity due to a high noise figure spectrum analyzer, a less expensive solution in a SAC is any number of wide band low noise figure preamplifiers that range in price from a few hundred dollars (or less from Mini-Circuits) to the HP8447X, which last time I checked was under $2000. on 3/26/04 2:44 PM, Ralph McDiarmid at [email protected] wrote: > > Does anyone in the group have experience with the need for a RF preselector > used in a 3m chamber? I suspect it is really necessary more for an OATS > where out-of-band strong ambients could present a problem for the > attenuator/mixer in a SA. > > Thanks, > > Ralph McDiarmid, AScT > Compliance Engineering Group > Xantrex Technology Inc. > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ieee-pses.org/ > > 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://www.ieeecommunities.org/emc-pstc > This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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://www.ieeecommunities.org/emc-pstc
