How are you measuring your phase? What is your reference? Are you = using a scope or ? Are you sure that the "loop" is the antenna or is something = else acting as the real antenna? Tom Dagostino Teraspeed(R) Labs 13610 SW Harness Lane Beaverton, OR 97008 503-430-1065 503-430-1285 FAX tom@xxxxxxxxxxxxx www.teraspeed.com Teraspeed Consulting Group LLC 121 North River Drive Narragansett, RI 02882 401-284-1827=20 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] = On Behalf Of Gene theBean Sent: Wednesday, May 28, 2008 2:53 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] loop antenna (mis)behavior I need some help from anyone who knows about fields and/or rf = propagation. =A0Here's my issue: I have a system with a transmitter sending a continuous 2 MHz signal out using a loop antenna. =A0The loop is electrically small, maybe 5" in = diameter and around 7 turns. =A0The receiving antennae (there's 2 of=A0them) are = likewise the same size and number of loops, and is around a couple of feet away = from the transmitter. =A0The RX antennae are just a couple of inches away = from each other. =A0They all share a common centerline. Also, the antenna = positions are fixed on a common, non-magnetic, core. Here's the problem: there is absolutely no phase change in either RX antenna. =A0That is, they are at 0 degrees phase, relative to one = another. Changing polarity on either RX antenna does not affect the relative = phase, where the expected phase shift would then be 180 degrees. In an experiment, using duplicate RX antenna sections, we discovered = that the very near field behavior is quite different than the far. =A0And, = this 'near' behavior only is true withing an inch or 2 of the transmitters. =A0There, the RX phase can changed by swapping=A0the polarity of = the=A0antenna leads.=A0=A0Fine.=A0=A0Moving=A0these 'floating' sections in the = vicinity of the TX=A0reveals phase inversions depending upon=A0the position. =A0But, = again, moving away from=A0this near field=A0area,=A0the=A0phasing is=A0always zero degrees=A0regardless of the=A0antenna polarity. =20 Anyone know what may be going on? =20 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: =20 //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu =20 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu