One reason would be that cable radiation efficiency is a function of electrical length. With any likely GTEM cell, the zone is not large enough to contain a half-wavelength of the cable at the lower frequencies.
Ken Javor ---------- >From: "Aschenberg, Mat" <[email protected]> >To: [email protected] >Subject: RE: GTEM Stuff >Date: Mon, Jan 15, 2001, 10:43 AM > > > It IS a problem for EUT-attached cables. > If the cables fit in the "zone" why are they not measured correctly? > Sincerely, > Mat Aschenberg > > > > Mathew Aschenberg > Agency Engineer > EchoStar Technologies Corporation > 90 Inverness Circle East > Englewood, CO 80112 > > >> -----Original Message----- >> From: Ken Javor [SMTP:[email protected]] >> Sent: Saturday, January 13, 2001 1:14 AM >> To: Aschenberg, Mat; [email protected] >> Subject: Re: GTEM Stuff >> >> >> The electric field is developed between septum and outer shell, so the >> field >> is vertically oriented at the center of the septum, but flaring towards >> the >> horizontal near septum edges, as in any TEM cell. This is not a drawback >> for an EUT small enough to be placed in multiple orientations between base >> and septum. It IS a problem for EUT-attached cables. These would need to >> be evaluated using another technique, such as the absorbing clamp. >> >> Disclaimer: I am fortunate not to have an employer to protect with the >> usual legalese about these being my opinions not my employers. But the >> bit >> about using a cable current measurement to separately control >> cable-sourced >> radiated emissions is controversial. All my experience indicates it is >> definitely the way to go, and I have a public paper trail so stating. But >> you could also find people adamantly opposed to this point-of-view. End >> of >> disclaimer. >> >> Ken Javor >> >> ---------- >> >From: "Aschenberg, Mat" <[email protected]> >> >To: [email protected] >> >Subject: GTEM Stuff >> >Date: Fri, Jan 12, 2001, 12:02 PM >> > >> >> > >> > Here is another specific question dealing with GTEM - OATS correlation. >> > >> > Is a GTEM cell horizontally or vertically polarized? >> > >> > Thanks for your help, >> > Mat >> > Mathew Aschenberg >> > Agency Engineer >> > EchoStar Technologies Corporation >> > 90 Inverness Circle East >> > Englewood, CO 80112 >> > >> > >> > >> > ------------------------------------------- >> > This message is from the IEEE EMC Society Product Safety >> > Technical Committee emc-pstc discussion list. >> > >> > To cancel your subscription, send mail to: >> > [email protected] >> > with the single line: >> > unsubscribe emc-pstc >> > >> > For help, send mail to the list administrators: >> > Jim Bacher: [email protected] >> > Michael Garretson: [email protected] >> > >> > For policy questions, send mail to: >> > Richard Nute: [email protected] >> > >> > >> >> ------------------------------------------- >> This message is from the IEEE EMC Society Product Safety >> Technical Committee emc-pstc discussion list. >> >> To cancel your subscription, send mail to: >> [email protected] >> with the single line: >> unsubscribe emc-pstc >> >> For help, send mail to the list administrators: >> Jim Bacher: [email protected] >> Michael Garretson: [email protected] >> >> For policy questions, send mail to: >> Richard Nute: [email protected] >> > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > To cancel your subscription, send mail to: > [email protected] > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Jim Bacher: [email protected] > Michael Garretson: [email protected] > > For policy questions, send mail to: > Richard Nute: [email protected] > > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected]
