[SI-LIST] Re: TDR Analsis Equipment..Tektronix vs Agilent?
- From: "Cavanna, Vicente Vaca (Sr. ; ProCurve ASICs)" <vicente.cavanna@xxxxxx>
- To: "Loyer, Jeff" <jeff.loyer@xxxxxxxxx>, <si-list@xxxxxxxxxxxxx>
- Date: Fri, 27 Apr 2007 18:31:25 -0000
Hi Jeff,
Please see my reply below.
Vince
> -----Original Message-----
> From: Loyer, Jeff [mailto:jeff.loyer@xxxxxxxxx]=20
> Sent: Wednesday, April 25, 2007 1:58 PM
> To: Cavanna, Vicente Vaca (Sr. ; ProCurve ASICs);=20
> si-list@xxxxxxxxxxxxx
> Subject: RE: [SI-LIST] Re: TDR Analsis Equipment..Tektronix=20
> vs Agilent?
>=20
> Hi Vicente,
>=20
> I would hesitate to imply to the general audience that VNA is=20
> going to be "easier" than TDR to measure lossy lines. In my=20
> experience/opinion, changing the energy of the VNA requires=20
> insight into the instrument that most folks don't utilize -=20
> it's not something to be done lightly.
> That's not to say I would rule it out, but it merits some=20
> careful study before doing it.
Yes I agree. "Easy is a very subjective word.
>=20
> And could I get some clarification on the TDR (I assume you=20
> were actually using TDT) limitation? =20
I use the word TDR to refer to the instrument. When I measure S21 I of
course perform a TDT measurement.
Were you measuring=20
> something where so much energy was lost that you couldn't=20
> measure the TDT skew? I.E., the waveform was such low=20
> voltage the scope couldn't see it?
Basically in my modeling, I oftentimes am interested in greater
bandwidth than that required of the channel to pass most of the energy
in the signal. Therefore I am typically dealing with much greater loss
than a practical channel offers at the Nyquist frequency of the signal.
To perform such measurements I have had to resort to increasing the
power in the stimulus. I do agree that for many measurements the TDR has
good enough dynamic range.
>=20
> Jeff Loyer
>=20
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx=20
> [mailto:si-list-bounce@xxxxxxxxxxxxx]
> On Behalf Of Cavanna, Vicente Vaca (Sr. ; ProCurve ASICs)
> Sent: Wednesday, April 25, 2007 12:03 PM
> To: dmitry.a.smolyansky@xxxxxxxxxxxxxx; tom@xxxxxxxxxxxxx;=20
> homer.si.mpson66@xxxxxxxxx; si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Re: TDR Analsis Equipment..Tektronix vs Agilent?
>=20
> Dima,
>=20
> You must admit that, if I make the line lossy enough, the=20
> through response (S21) will eventually be low enough as to be=20
> buried in noise.
> If you cannot increase the energy in the stimulus you are=20
> stuck. You cannot measure lines that are more lossy. If you=20
> can increase the stimulus energy you can still perform a=20
> valid measurement. That is all I was trying to say.=3D20
>=20
> In practice where I have reached such limitations with a TDR=20
> is when I was trying to measure phase accurately (to measure=20
> skew). It was much easier to get accurate measurements on=20
> lossy lines with a VNA.
>=20
> Vicente
>=20
> > -----Original Message-----
> > From: dmitry.a.smolyansky@xxxxxxxxxxxxxx=3D20
> > [mailto:dmitry.a.smolyansky@xxxxxxxxxxxxxx]=3D20
> > Sent: Wednesday, April 25, 2007 11:46 AM
> > To: Cavanna, Vicente Vaca (Sr. ; ProCurve ASICs);=3D20 =20
> >tom@xxxxxxxxxxxxx; homer.si.mpson66@xxxxxxxxx; si-list@xxxxxxxxxxxxx
> > Subject: RE: [SI-LIST] Re: TDR Analsis Equipment..Tektronix=3D20 vs =
> >Agilent?
> >=3D20
> > Vicente,
> >=3D20
> > Not sure why you need to increase the energy to test lossy lines...
> > Never heard of anybody doing it that way. Seems like to=3D20 =20
> >characterize lossy lines, you just need adequate dynamic=3D20 =
range,=20
> >which TDRs provide amply.
> >=3D20
> > Thanks,
> > =3D20
> > Dima Smolyansky
> > Product Marketing Manager
> > Tektronix, Inc.
> > P.O. Box 500, MS 39-111
> > Beaverton, OR 97077-0001
> > 503-627-7180
> > 503-627-2260 (fax)
> >=3D20
> >=3D20
> > -----Original Message-----
> > From: Cavanna, Vicente Vaca (Sr. ; ProCurve ASICs)=3D20 =20
> >[mailto:vicente.cavanna@xxxxxx]
> > Sent: Wednesday, April 25, 2007 11:41 AM
> > To: Smolyansky, Dmitry A; tom@xxxxxxxxxxxxx;=3D20 =20
> >homer.si.mpson66@xxxxxxxxx; si-list@xxxxxxxxxxxxx
> > Subject: RE: [SI-LIST] Re: TDR Analsis Equipment..Tektronix=3D20 vs =
> >Agilent?
> >=3D20
> > Yes, I know VNA energy is not uniform either, nor, as I said=3D20 =20
> >earlier, does it need to be. There just has to be=20
> sufficient=3D20 energy=20
> >at each frequency to make an accurate measurement.
> >=3D20
> > The main point (in fact the only point) I was trying to make=3D20 =
is=20
> >that, with a VNA, one can increase the energy from the=3D20 stimulus =
> >whereas with the TDRs I am familiar with (my=3D20 familiarity=20
> does not=20
> >extend to any recent Tecktronix=3D20
> > instruments) one cannot easily increase the energy.
> > The ability to increase the energy is very useful (and may=20
> well become
> > essential) when testing lossy lines (a very practical scenario).
> >=3D20
> > Vicente
> >=3D20
> > > -----Original Message-----
> > > From: dmitry.a.smolyansky@xxxxxxxxxxxxxx
> > > [mailto:dmitry.a.smolyansky@xxxxxxxxxxxxxx]
> > > Sent: Wednesday, April 25, 2007 10:20 AM
> > > To: Cavanna, Vicente Vaca (Sr. ; ProCurve ASICs);=3D20
> > tom@xxxxxxxxxxxxx;=3D20
> > > homer.si.mpson66@xxxxxxxxx; si-list@xxxxxxxxxxxxx
> > > Subject: RE: [SI-LIST] Re: TDR Analsis=20
> Equipment..Tektronix vs=3D20 =20
> > >Agilent?
> > >=3D20
> > > VNA energy is not uniform either. It is being "uniformized"=3D20 =20
> > >using calibration. The same applies for TDR. And while the=3D20
> > TDR-based=3D20
> > > S-parameter dynamic range is lower than that of a VNA, it=3D20
> > is more than=3D20
> > > adequate for serial data applications.
> > > You get about -70 dB of dynamic range at DC and -40 dB at 50 GHz
> on=3D20
> > > Tektronix equipment. I would not recommend this for=3D20
> > microwave filter=3D20
> > > design, but for serial data it is perfect.
> > > As a side bonus, you get true differential - individual source
> per=3D20
> > > each channel, avoiding any switching errors and ensuring=20
> accurate=3D20 =20
> > >non-linear and active device characterization.
> > >=3D20
> > > Thanks,
> > > =3D20
> > > Dima Smolyansky
> > > Tektronix, Inc.
> > > P.O. Box 500, MS 39-111
> > > Beaverton, OR 97077-0001
> > > 503-627-7180
> > > 503-627-2260 (fax)
> > >=3D20
> > >=3D20
> > > -----Original Message-----
> > > From: si-list-bounce@xxxxxxxxxxxxx
> > > [mailto:si-list-bounce@xxxxxxxxxxxxx]
> > > On Behalf Of Cavanna, Vicente Vaca (Sr. ; ProCurve ASICs)
> > > Sent: Wednesday, April 25, 2007 9:38 AM
> > > To: tom@xxxxxxxxxxxxx; homer.si.mpson66@xxxxxxxxx;=3D20 =20
> > >si-list@xxxxxxxxxxxxx
> > > Subject: [SI-LIST] Re: TDR Analsis Equipment..Tektronix=20
> vs Agilent?
> > >=3D20
> > > Hi Tom,
> > > But it is not too important to get the same energy over the=3D20 =20
> > >measurement frequency range (after all, the energy in the=3D20
> > TDR stimulus=3D20
> > > is hardly uniform over frequency). What is of primary=3D20
> > importance is to=3D20
> > > have
> > > *sufficient* energy at the detector to overcome the noise (i.e.
> > > sufficient signal to noise ratio) at all frequencies of=3D20
> > interest. I do=3D20
> > > agree of course that the DUT plays a huge part in how=20
> much energy=3D20 =20
> > >reaches the detector.
> > > Vicente
> > >=3D20
> > > > -----Original Message-----
> > > > From: si-list-bounce@xxxxxxxxxxxxx=3D3D20 =3D20=20
> > > >[mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Tom Dagostino
> > > > Sent: Tuesday, April 24, 2007 6:32 PM
> > > > To: Cavanna, Vicente Vaca (Sr. ; ProCurve ASICs);=3D3D20=3D20=20
> > > >homer.si.mpson66@xxxxxxxxx; si-list@xxxxxxxxxxxxx
> > > > Subject: [SI-LIST] Re: TDR Analsis Equipment..Tektronix=3D20
> > vs Agilent?
> > > >=3D3D20
> > > > Vicente
> > > >=3D3D20
> > > > It is not a problem getting a large amount of energy to
> > > the=3D3D20 DUT,
> > > >it is a problem of getting the same energy over the=3D3D20 =3D20
> > measurement=3D20
> > > >frequency range. =3D3D3D If there is an inductive=3D3D20 launch =
it
> > > will act
> > > >as a low pass filter. Thus the energy=3D3D20 will be different
> at=3D20
> > > >different frequencies.
> > > >=3D3D20
> > > > Tom Dagostino
> > > > Teraspeed(R) Labs
> > > > 13610 SW Harness Lane
> > > > Beaverton, OR 97008
> > > > 503-430-1065
> > > > tom@xxxxxxxxxxxxx=3D3D3D20
> > > > www.teraspeed.com=3D3D3D20
> > > >=3D3D20
> > > > Teraspeed Consulting Group LLC
> > > > 121 North River Drive
> > > > Narragansett, RI 02882
> > > > 401-284-1827
> > > >=3D3D20
> > > > -----Original Message-----
> > > > From: si-list-bounce@xxxxxxxxxxxxx=3D3D20 =3D20=20
> > > >[mailto:si-list-bounce@xxxxxxxxxxxxx] =3D3D3D On Behalf Of =3D
> Cavanna,=3D3D20=3D20
> > > >Vicente Vaca (Sr. ; ProCurve ASICs)
> > > > Sent: Tuesday, April 24, 2007 5:20 PM
> > > > To: homer.si.mpson66@xxxxxxxxx; si-list@xxxxxxxxxxxxx
> > > > Subject: [SI-LIST] Re: TDR Analsis Equipment..Tektronix=3D20
> > vs Agilent?
> > > >=3D3D20
> > > >=3D3D20
> > > > With a VNA one can increase the power level of the
> > > stimulus=3D3D20 and
> > > >get =3D3D3D more energy into and through the DUT even when
> > > the=3D3D20 DUT is
> > > >lossy and/or =3D3D3D extremely reflective. With a TDR this=3D3D20 =
=3D20
> > is not as=3D20
> > > >easy to do; in fact the TDRs I =3D3D3D have used do not=3D3D20 =
=3D20
> > permit such=3D20
> > > >control. Vicente =3D3D20
> > > > > -----Original Message-----
> > > > > From: si-list-bounce@xxxxxxxxxxxxx=3D3D3D3D20 =
=3D3D3D20=3D3D20=3D20=20
> > > > >[mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Peter J
> > > > > Sent: Tuesday, April 24, 2007 9:36 AM
> > > > > To: si-list@xxxxxxxxxxxxx
> > > > > Subject: [SI-LIST] Re: TDR Analsis=20
> Equipment..Tektronix vs=3D3D20
> > > > Agilent?=3D3D3D20=3D3D20
> > > > >=3D3D3D3D20 Hi, The biggest problem in using a TDR or VNA =3D
> for=3D3D20
> > > > that matter=3D3D20
> > > > >is=3D3D3D3D20 to get enough energy into the DUT since even a =
=3D
> very=3D3D20
> > > > small=3D3D3D3D20 =3D3D20
> > > > >inductance at the connection point from the TDR to the=3D3D20
> > > > DUT=3D3D3D3D20 will=3D3D20
> > > > >give an insertion loss. It's possible to get a
> > > return=3D3D3D3D20 loss of
> > > =3D3D
> > >=3D20
> > > > >-20dB at 5GHz if you work hard. At 50 GHz it's hard=3D3D3D3D20 =
=3D
> to=3D3D20
> > > > get -3 dB=3D3D20
> > > > >RL which means that half of the power will enter=3D3D3D3D20 =
=3D
> the=3D3D20
> > > > DUT and the=3D3D20
> > > > >rest is wasted. By using a VNA it is possible=3D3D3D3D20=20
> to make a
> > > TRL=3D3D20
> > > > >calibration kit and remove the effect of the=3D3D3D3D20 =3D3D20
> > > > testsystem and only=3D3D20
> > > > >get the DUT characteristics.
> > > > > I use a short pigtail with a thin semirigid coax instead
> > > of a=3D3D3D3D20
> > > =3D3D
> > > =3D3D20
> > > > >probe when I do measurements with the TDR(tektronix).=3D20
> > > It=3D3D3D3D20 =3D3D20
> > > > >increases the accuracy a great deal.
> > > > >=3D3D3D3D20
> > > > > BR
> > > > > Peter
> > > > >=3D3D3D3D20
> > > > > -----Original Message-----
> > > > >=3D3D3D3D20
> > > > > From: si-list-bounce@xxxxxxxxxxxxx =3D3D20
> > > >=3D20
> > >=3D20
> >=20
> [*mailto:si-list-bounce@xxxxxxxxxxxxx*<si-list-bounce@xxxxxxxxxxxxx>]
> > > > > On Behalf Of ext Asbenson, Lyndell L =3D3D3D3D20
> > > > > Sent: 24. april 2007 02:27
> > > > >=3D3D3D3D20
> > > > > To: heidi.barnes@xxxxxxxxxx; si-list@xxxxxxxxxxxxx =3D3D3D3D20
> > > > > Cc: timothy.j.nash@xxxxxxxx; tom_cip_11551@xxxxxxxxx =
=3D3D3D3D20
> > > > > Subject: [SI-LIST] Re: TDR Analsis Equipment..Tektronix
> > > vs Agilent?
> > > > >=3D3D3D3D20
> > > > > Dedicated TDR is much easer to setup then going the VNA=3D3D20
> > > > route -Lyndell=3D3D20
> > > > >=3D3D3D3D20 -----Original Message----- =3D3D3D3D20
> > > > > From: si-list-bounce@xxxxxxxxxxxxx =3D20
> > >=20
> [*mailto:si-list-bounce@xxxxxxxxxxxxx*<si-list-bounce@xxxxxxxxxxxxx>
> > > > > ]
> > > > >=3D3D3D3D20
> > > > > On Behalf Of Barnes, Heidi
> > > > >=3D3D3D3D20
> > > > > Sent: Monday, April 23, 2007 12:17 PM =3D3D3D3D20
> > > > > To: si-list@xxxxxxxxxxxxx
> > > > >=3D3D3D3D20
> > > > > Cc: timothy.j.nash@xxxxxxxx; tom_cip_11551@xxxxxxxxx =
=3D3D3D3D20
> > > > > Subject: [SI-LIST] Re: TDR Analsis Equipment..Tektronix
> > > vs Agilent?
> > > > >=3D3D3D3D20
> > > > > Hi Tom,
> > > > >=3D3D3D3D20
> > > > > Tim is correct in that probing is not a simple task. If=3D3D20
> > > > you=3D3D3D3D20 have=3D3D20
> > > > >the time and patience, a Vector Network Analyzer
> > > with=3D3D3D3D20 PCB=3D3D20
> > > > >Thru-Reflect-Line Calibration standards can provide=20
> a=3D3D3D3D20 =3D
> =3D3D20
> > > > method for=3D3D20
> > > > >getting measured electrical data for a PCB=3D3D3D3D20 =3D20
> > structure that =3D3D
> > > does=3D3D20
> > > > >not include the probes or connectorized=3D3D3D3D20
> > > transitions on to the
> > > =3D3D
> > >=3D20
> > > > >printed circuit board. The S-Parameter=3D3D3D3D20 data can =3D
> then=3D3D20
> > > > be converted=3D3D20
> > > > >to time domain for TDR analysis of=3D3D3D3D20 the=3D20
> > discontinuities and
> > > a=3D3D20
> > > > >40GHz box will give you around an=3D3D3D3D20 18pS rise time =
=3D
> pulse=3D3D20
> > > > (an edge=3D3D20
> > > > >that is ~100mils long for a PCB=3D3D3D3D20 dielectric constant =
=3D
> of=3D3D20
> > > > ~4) which=3D3D20
> > > > >gives a significant amount=3D3D3D3D20 of detail (50mils is =3D
> rather=3D3D20
> > > > ambitious=3D3D20
> > > > >unless you have money=3D3D3D3D20 for the top end 110GHz=3D20
> > VNA's or 8pS =3D3D
> > > rise=3D3D20
> > > > >time TDR scopes).=3D3D3D3D20 The other thing to think about
> > > is that most
> > > =3D3D
> > >=3D20
> > > > >applications=3D3D3D3D20 running about 3Gbps are differential =
=3D
> so=3D3D20
> > > > it is also=3D3D20
> > > > >nice to=3D3D3D3D20 have a 4-Port system for measurements.
> > > > >=3D3D3D3D20
> > > > > Regards,
> > > > >=3D3D3D3D20
> > > > > Heidi
> > > > >=3D3D3D3D20
> > > > > -----Original Message-----
> > > > >=3D3D3D3D20
> > > > > From: si-list-bounce@xxxxxxxxxxxxx =3D20
> > >=20
> [*mailto:si-list-bounce@xxxxxxxxxxxxx*<si-list-bounce@xxxxxxxxxxxxx>
> > > > > ]
> > > > >=3D3D3D3D20
> > > > > On Behalf Of Nash, Timothy J
> > > > >=3D3D3D3D20
> > > > > Sent: Monday, April 23, 2007 11:33 AM =3D3D3D3D20
> > > > > To: tom_cip_11551@xxxxxxxxx; si-list@xxxxxxxxxxxxx =3D3D3D3D20
> > > > > Subject: [SI-LIST] Re: TDR Analsis Equipment..Tektronix
> > > vs Agilent?
> > > > >=3D3D3D3D20
> > > > > Hi, Tom.
> > > > >=3D3D3D3D20
> > > > > I have tried using a Tektronix TDR (I'm not sure of=20
> the=3D3D3D3D20
> > > > > model) to probe PCBs before, and found that what probe=3D3D20
> > > > you=3D3D3D3D20 were=3D3D20
> > > > >using, and WHAT you were probing, can make or break
> > > your=3D3D3D3D20 =3D3D20
> > > > >measurement. We were using a hand-held pressure-actuated
> > > type=3D3D3D3D20
> > > =3D3D
> > >=3D20
> > > > >probe and simply bending your wrist a little would change
> > > the=3D3D3D3D20
> > > =3D3D
> > >=3D20
> > > > >response. We had a tough time even discerning between=3D20
> > two=3D3D3D3D20 =3D3D
> > > vias=3D3D20
> > > > >spaced an inch apart from each other. I believe the=3D3D3D3D20 =
=3D
> =3D3D20
> > > > probes used=3D3D20
> > > > >by most PCB manufacturers are on a robotic=20
> arm=3D3D3D3D20 and they
> > > are=3D3D20
> > > > >probing PCB coupons that have pre-defined TDR=3D3D3D3D20 =
=3D3D20
> > > > features. I found=3D3D20
> > > > >it very difficult to glean much useful info=3D3D3D3D20 from =
=3D
> real=3D3D20
> > > > PCB traces=3D3D20
> > > > >when the discontinuities were as close=3D3D3D3D20 =20
> together as=3D3D20
> > > > what you are=3D3D20
> > > > >describing. I don't believe this was=3D3D3D3D20 a fault of =3D
> the=3D3D20
> > > > scope - just=3D3D20
> > > > >a function of the probing method=3D3D3D3D20 and the =
feature=3D3D20
> > > > constraints of=3D3D20
> > > > >the PCB.
> > > > >=3D3D3D3D20
> > > > > Tim
> > > > >=3D3D3D3D20
> > > > >=3D3D3D3D20
> > > > >=3D3D3D3D20
> > > > >=3D3D3D3D20
> > > > >=3D3D3D3D20
> > > > > -----Original Message-----
> > > > >=3D3D3D3D20
> > > > > From: si-list-bounce@xxxxxxxxxxxxx =3D20
> > >=20
> [*mailto:si-list-bounce@xxxxxxxxxxxxx*<si-list-bounce@xxxxxxxxxxxxx>
> > > > > ]
> > > > >=3D3D3D3D20
> > > > > On Behalf Of tom_cip_11551
> > > > >=3D3D3D3D20
> > > > > Sent: Monday, April 23, 2007 10:47 AM =3D3D3D3D20
> > > > > To: si-list@xxxxxxxxxxxxx
> > > > >=3D3D3D3D20
> > > > > Subject: [SI-LIST] TDR Analsis Equipment..Tektronix=20
> vs Agilent?
> > > > >=3D3D3D3D20
> > > > > Hi to the Signal Integrity community.
> > > > >=3D3D3D3D20
> > > > > I am looking for a set of equipment with wich to do=3D3D20
> > > > TDR=3D3D3D3D20 analysis=3D3D20
> > > > >on=3D3D3D3D3D3D20 high speed PCB structures. We are=20
> now=3D3D3D3D20 =3D
> =3D3D20
> > > > building boards=3D3D20
> > > > >to run at=3D3D3D3D3D3D20 speeds of 3 Gb/s or faster=20
> and=3D3D3D3D20 =3D
> I=3D3D20
> > > > would like to=3D3D20
> > > > >resolve=3D3D3D3D3D3D20 discontinuites within, say, =
50=3D3D3D3D20 =3D
> mils=3D3D20
> > > > to 80 mils=3D3D20
> > > > >of each other.
> > > > >=3D3D3D3D20
> > > > > I have gotten quotes from Tektronix and Agilent for
> > > TDR=3D3D3D3D20 =3D3D20
> > > > >equipment. =3D3D3D3D3D3D20 =3D3D3D3D20 The Tektronix=20
> system consists
> =3D
> of
> > > the=3D3D20
> > > > >DSA8200 digital sampling=3D3D3D3D20 =3D3D3D3D3D=20
> scope,=3D3D3D3D3D3D20
> > > the 80E04
> > > =3D3D
> > > TDR=3D3D20
> > > > >sampling module and the =3D3D3D
> > > > 80SICON=3D3D3D3D20
> > > > > signal integrity and=3D3D3D3D3D3D20 failure analysis software =
=3D
> (a=3D3D20
> > > > $20K=3D3D3D3D20 =3D3D20
> > > > >item by itself).
> > > > >=3D3D3D3D20
> > > > > The Agilent system consists of the 86100C scope, the=3D20
> > 54754A=3D3D3D3D20
> > > =3D3D20
> > > > >TDR=3D3D3D3D3D3D20 module and various other software=20
> programs for =3D
> =3D3D
> > > S=3D3D3D3D20 =3D3D20
> > > > >parameters, Jitter=3D3D3D3D3D3D20 analysis, etc.
> > > > >=3D3D3D3D20
> > > > > I am wondering what the Signal Integrity community at=3D20
> > large=3D3D3D3D20
> > > =3D3D20
> > > > >is=3D3D3D3D3D3D20 using.
> > > > > Which system is more popular and, most important,
> > > cost=3D3D3D3D3D3D20 =3D3D
> > > =3D3D3D3D
> > > > effective?
> > > > >=3D3D3D3D20
> > > > > What are some of the advantages and drawbacks of each?
> > > > >=3D3D3D3D20
> > > > > Are there other solutions on the market that are more
> cost=3D3D20=3D20
> > > > >effective?=3D3D3D20 =3D3D3D3D20 Thank You =3D3D3D3D20 Tom=20
> =3D3D3D3D20 =3D
> =3D3D3D3D20 =3D3D
> > > =3D3D3D3D20
> > > > >=3D20
> > ------------------------------------------------------------------
> > > > >=3D3D3D3D20
> > > > > To unsubscribe from si-list:
> > > > >=3D3D3D3D20
> > > > > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the=3D3D20
> > > > Subject field=3D3D20
> > > > >=3D3D3D3D20 or to administer your membership from a web=20
> page, go =3D
> to:
> > > > >=3D3D3D3D20
> > > > > *//www.freelists.org/webpage/si-list*<http://www.freelist
> > > > s.org/webpage/si-list>
> > > > >=3D3D3D3D20
> > > > > For help:
> > > > >=3D3D3D3D20
> > > > > si-list-request@xxxxxxxxxxxxx with 'help' in the =
Subject=3D3D20
> > > > field =3D3D3D3D20=3D3D20
> > > > >=3D3D3D3D20 =3D3D3D3D20 List technical documents are available =
at:
> > > > >=3D3D3D3D20
> > > > > *http://www.si-list.net* <http://www.si-list.net/>
> > > =3D3D3D3D20 List=3D3D20
> > > > >archives are viewable at: =3D3D3D3D3D3D20 =3D3D3D3D20 =
=3D3D20=3D20=20
> > > > >*//www.freelists.org/archives/si-list*<http://www.freelis
> > > > ts.org/archives/si-list>
> > > > >=3D3D3D3D20
> > > > > or at our remote archives:
> > > > >=3D3D3D3D20 =3D3D
> > > *http://groups.yahoo.com/group/si-list/messages*<http://groups
> > > > .yahoo.com/group/si-list/messages>
> > > > >=3D3D3D3D20
> > > > > Old (prior to June 6, 2001) list archives are viewable=3D20
> > at: =3D3D3D3D20
> > > > > *http://www.qsl.net/wb6tpu* <http://www.qsl.net/wb6tpu>
> > > =3D3D3D3D20 =3D3D20
> > > > >=3D3D3D3D3D3D20 =3D3D3D3D20
> > > > >=3D20
> > ------------------------------------------------------------------
> > > > >=3D3D3D3D20
> > > > > To unsubscribe from si-list:
> > > > >=3D3D3D3D20
> > > > > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the=3D3D20
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> > > > >=3D3D3D3D20 or to administer your membership from a web=20
> page, go =3D
> to:
> > > > >=3D3D3D3D20
> > > > > *//www.freelists.org/webpage/si-list*<http://www.freelist
> > > > s.org/webpage/si-list>
> > > > >=3D3D3D3D20
> > > > > For help:
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> > > > > si-list-request@xxxxxxxxxxxxx with 'help' in the =
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> > > > field =3D3D3D3D20=3D3D20
> > > > >=3D3D3D3D20 =3D3D3D3D20 List technical documents are available =
at:
> > > > >=3D3D3D3D20
> > > > > *http://www.si-list.net* <http://www.si-list.net/>
> > > =3D3D3D3D20 List=3D3D20
> > > > >archives are viewable at: =3D3D3D3D3D3D20 =3D3D3D3D20 =
=3D3D20=3D20=20
> > > > >*//www.freelists.org/archives/si-list*<http://www.freelis
> > > > ts.org/archives/si-list>
> > > > >=3D3D3D3D20
> > > > > or at our remote archives:
> > > > >=3D3D3D3D20 =3D3D
> > > *http://groups.yahoo.com/group/si-list/messages*<http://groups
> > > > .yahoo.com/group/si-list/messages>
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> > > > > Old (prior to June 6, 2001) list archives are viewable=3D20
> > at: =3D3D3D3D20
> > > > > *http://www.qsl.net/wb6tpu* <http://www.qsl.net/wb6tpu>
> > > =3D3D3D3D20 =3D3D20
> > > > >=3D3D3D3D3D3D20 =3D3D3D3D20
> > > > >=3D20
> > ------------------------------------------------------------------
> > > > >=3D3D3D3D20
> > > > > To unsubscribe from si-list:
> > > > >=3D3D3D3D20
> > > > > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the=3D3D20
> > > > Subject field=3D3D20
> > > > >=3D3D3D3D20 or to administer your membership from a web=20
> page, go =3D
> to:
> > > > >=3D3D3D3D20
> > > > > *//www.freelists.org/webpage/si-list*<http://www.freelist
> > > > s.org/webpage/si-list>
> > > > >=3D3D3D3D20
> > > > > For help:
> > > > >=3D3D3D3D20
> > > > > si-list-request@xxxxxxxxxxxxx with 'help' in the =
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> > > > field =3D3D3D3D20=3D3D20
> > > > >=3D3D3D3D20 =3D3D3D3D20 List technical documents are available =
at:
> > > > >=3D3D3D3D20
> > > > > *http://www.si-list.net* <http://www.si-list.net/>
> > > =3D3D3D3D20 List=3D3D20
> > > > >archives are viewable at: =3D3D3D3D3D20 =3D3D3D3D20 =
=3D3D20=3D20=20
> > > > >*//www.freelists.org/archives/si-list*<http://www.freelis
> > > > ts.org/archives/si-list>
> > > > >=3D3D3D3D20
> > > > > or at our remote archives:
> > > > >=3D3D3D3D20 =3D3D
> > > *http://groups.yahoo.com/group/si-list/messages*<http://groups
> > > > .yahoo.com/group/si-list/messages>
> > > > >=3D3D3D3D20
> > > > > Old (prior to June 6, 2001) list archives are viewable=3D20
> > at: =3D3D3D3D20
> > > > > *http://www.qsl.net/wb6tpu* <http://www.qsl.net/wb6tpu>=3D3D20
> > > > =3D3D3D3D20 =3D3D3D3D3D20=3D3D20
> > > > >=3D3D3D3D20
> > > > >=3D20
> > ------------------------------------------------------------------
> > > > >=3D3D3D3D20
> > > > > To unsubscribe from si-list:
> > > > >=3D3D3D3D20
> > > > > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the=3D3D20
> > > > Subject field=3D3D20
> > > > >=3D3D3D3D20 or to administer your membership from a web=20
> page, go =3D
> to:
> > > > >=3D3D3D3D20
> > > > > *//www.freelists.org/webpage/si-list*<http://www.freelist
> > > > s.org/webpage/si-list>
> > > > >=3D3D3D3D20
> > > > > For help:
> > > > >=3D3D3D3D20
> > > > > si-list-request@xxxxxxxxxxxxx with 'help' in the =
Subject=3D3D20
> > > > field =3D3D3D3D20=3D3D20
> > > > >=3D3D3D3D20 =3D3D3D3D20 List technical documents are available =
at:
> > > > >=3D3D3D3D20
> > > > > *http://www.si-list.net* <http://www.si-list.net/>
> > > =3D3D3D3D20 List=3D3D20
> > > > >archives are viewable at:
> > > > >=3D3D3D3D20
> > > > > *//www.freelists.org/archives/si-list*<http://www.freelis
> > > > ts.org/archives/si-list>
> > > > >=3D3D3D3D20
> > > > > or at our remote archives:
> > > > >=3D3D3D3D20 =3D3D
> > > *http://groups.yahoo.com/group/si-list/messages*<http://groups
> > > > .yahoo.com/group/si-list/messages>
> > > > >=3D3D3D3D20
> > > > > Old (prior to June 6, 2001) list archives are viewable=3D20
> > at: =3D3D3D3D20
> > > > > *http://www.qsl.net/wb6tpu* <http://www.qsl.net/wb6tpu>=3D20
> > =3D3D3D3D20 =3D3D
> > > =3D3D3D3D20
> > > > >=3D20
> > ------------------------------------------------------------------
> > > > > To unsubscribe from si-list:
> > > > > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the=3D3D20
> > > > Subject field=3D3D20
> > > > >=3D3D3D3D20 or to administer your membership from a web=20
> page, go =3D
> to:
> > > > > //www.freelists.org/webpage/si-list
> > > > >=3D3D3D3D20
> > > > > For help:
> > > > > si-list-request@xxxxxxxxxxxxx with 'help' in the =
Subject=3D3D20
> > > > field =3D3D3D3D20=3D3D20
> > > > >=3D3D3D3D20 List technical documents are available at:
> > > > > http://www.si-list.net =3D3D3D3D20
> > > > > List archives are viewable at: =3D3D3D3D20
> > > > > //www.freelists.org/archives/si-list
> > > > > or at our remote archives:
> > > > > http://groups.yahoo.com/group/si-list/messages
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> > > > > http://www.qsl.net/wb6tpu
> > > > > =3D3D3D3D20
> > > > >=3D3D3D3D20
> > > > >=3D3D3D3D20
> > > >=20
> ------------------------------------------------------------------
> > > > To unsubscribe from si-list:
> > > > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the
> > > Subject field
> > > >=3D3D20 or to administer your membership from a web page, go to:
> > > > //www.freelists.org/webpage/si-list
> > > >=3D3D20
> > > > For help:
> > > > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject
> > > field =3D3D20 =3D3D20
> > > >List technical documents are available at:
> > > > http://www.si-list.net =3D3D20
> > > > List archives are viewable at: =3D3D3D20
> > > > //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
> > > > =3D3D3D20
> > > >=3D3D20
> > > >=3D3D20
> > > >=20
> ------------------------------------------------------------------
> > > > To unsubscribe from si-list:
> > > > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the
> > > Subject field
> > > >=3D3D20 or to administer your membership from a web page, go to:
> > > > //www.freelists.org/webpage/si-list
> > > >=3D3D20
> > > > For help:
> > > > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject
> > > field =3D3D20 =3D3D20
> > > >List technical documents are available at:
> > > > http://www.si-list.net =3D3D20
> > > > List archives are viewable at: =3D3D20
> > > > //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
> > > > =3D3D20
> > > >=3D3D20
> > > >=3D3D20
> > > ------------------------------------------------------------------
> > > To unsubscribe from si-list:
> > > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the=3D20
> > Subject field
> > >=3D20
> > > or to administer your membership from a web page, go to:
> > > //www.freelists.org/webpage/si-list
> > >=3D20
> > > For help:
> > > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject=20
> field =3D20=20
> > >=3D20 List technical documents are available at:
> > > http://www.si-list.net =3D20
> > > List archives are viewable at: =3D20
> > > //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
> > > =3D20
> > >=3D20
> > >=3D20
> >=3D20
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>=20
> or to administer your membership from a web page, go to:
> //www.freelists.org/webpage/si-list
>=20
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>=20
>=20
> List technical documents are available at:
> http://www.si-list.net
>=20
> 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
>=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:
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Old (prior to June 6, 2001) list archives are viewable at:
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