Mr. Woodgate asks: Do any active loop antennas feed the actual loop into a zero-impedance load, thus producing a response independent of frequency?"
Walker Scientific does that very thing. Check out the model VLF-80D. Ken Javor Phone: (256) 650-5261 > From: John Woodgate <[email protected]> > Date: Tue, 9 Jun 2009 15:44:25 +0100 > To: <[email protected]> > Subject: Re: [PSES] Measurement Accuracy and antenna factors > > In message > <9d04b979323dcd428297dda95108893e0287f...@bb-corp-ex2.corp.cubic.cub>, > dated Tue, 9 Jun 2009, "Price, Edward" <[email protected]> writes: > >> In my example of the factor set of an H-field loop antenna, which I >> used because the amplitude might go from 28 dB @ 300 kHz to 88 dB @ 20 >> Hz (data from my EMCO 7604 passive loop), I would expect the >> lower-frequency end of the plot to be linear. Yet, when I lay a >> straight-edge to the actual plot, I find a few slights humps and bumps. > > If that's purely a passive loop, its response is calculable, and any > humps and bumps must be due to measurement artefacts. However, that > would give an antenna factor of 28 dB at 200 kHz, not 300 kHz. Do you > know the inductance of the loop? > > Do any active loop antennas feed the actual loop into a zero-impedance > load, thus producing a response independent of frequency? >> >> Are these deviations attributable to my cal lab's equipment errors or >> setup errors? Is my straight-edge warped? Or could these deviations be >> real? While watching for the signs of measurement overloads or >> noise-floor limitations, I also have to admit that maybe there is >> something in my probe which creates tiny resonances or coupling effects >> that really does affect the theoretical results. > > You aren't going to get any resonances due to micro-mechanical > structures in the 20 Hz to 300 kHz range. > -- > OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk > Things can always get better. But that's not the only option. > John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK > > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to > <[email protected]> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieeecommunities.org/emc-pstc > Graphics (in well-used formats), large files, etc. can be posted to that URL. > > Website: http://www.ieee-pses.org/ > Instructions: http://listserv.ieee.org/request/user-guide.html > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher: <[email protected]> > David Heald: <[email protected]> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
