A couple of thoughts: The use of a VNA for measuring NSA is an incredibly valuable tool if the site fails. On a standard "true" OATS (no enclosure) where single point sense antenna location is accepted, it's overkill, but certainly acceptable as long as the computer talking to the VNA can do the maximum capture as Neven noted below.
The best thing about a VNA is the ability to take phase data from several different receive antenna positions to try to understand site deficiencies. While not as easily evaluated as gated time domain information, the FFT of the multiple frequency/phase domain points can greatly help localizing an offending site feature. At lower frequencies, the phase information from the VNA adds a great deal of information with respect to the SA/tracking generator combo. The higher the frequency, the less this matters. Best of luck! Brent DeWitt Loveland, CO > -----Original Message----- > From: [email protected] > [mailto:[email protected]]On Behalf Of > [email protected] > Sent: Monday, April 05, 2004 9:44 AM > To: [email protected] > Subject: RE: VNA's for NSA > > > > I haven't done it in long time, but NSA measurement is esentially > insertion loss measurement between two antennas. So you calibrate > "through" at the feed points of your both antennas (this > calibrates out the cable) and measure S21. > > VNAs that I know don't have "max hold" function so you may need > SW to capture data for all antenna heights and merge them to > obtain max values. > > Alternatively, you could use a spectrum analyzer with tracking > generator instead of the VNA. You do one calibration "through" > measurement though the cables and store it in one trace. Then > connect the antennas and use another trace for antenna > insertion-loss measurement. Then calculate meas/reference (usualy > available on the SA) to take out the cable loss from your measurement. > > The rest is massaging the numbers. > > Neven > > > > -----Original Message----- > > From: Derek Walton [mailto:[email protected]] > > Sent: Sunday, April 04, 2004 10:37 PM > > To: [email protected] > > Subject: VNA's for NSA > > > > > > Hi All, > > > > I'm looking at using a VNA to perform NSA measurements. > > > > Can anyone direct me to a detailed procedure? > > > > Thanks, > > -- > > Derek N. Walton > > L F Research > > Poplar Grove, IL 61065, USA > > > > > > > > The NSA is a bit tight about handing out procedures detailing TEMPEST or > > COMSEC testing. You should go back to your contracting officer > for guidance. > > If you want, I can put you in touch with a Navy TEMPEST contact who does > > field testing and could provide you with more authoritative advice. > > > > Regards, > > > > Ed > > > > Ed Price > > [email protected] WB6WSN > > NARTE Certified EMC Engineer & Technician > > Electromagnetic Compatibility Lab > > Cubic Defense Applications > > San Diego, CA USA > > 858-505-2780 (Voice) > > 858-505-1583 (Fax) > > Military & Avionics EMC Is Our Specialty > > > > ------------------------------------------- > > > 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 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
