[SI-LIST] Re: Coaxial Cable crosstalk
- From: "Daniel, Erik S., Ph.D." <Daniel.Erik@xxxxxxxx>
- To: deibele@xxxxxxx, si-list@xxxxxxxxxxxxx
- Date: Tue, 5 Feb 2002 10:06:37 -0600
Craig-
I think you're right -- this is a hard problem. In our experience with good
quality coax cables in the lab, the crosstalk is so low (easily better than
-100 dB) that I think you'd find it extremely hard to predict -- much easier
to measure with a good spectral quality signal source and a spectrum
analyzer with fairly low noise / narrow resolution bandwidth. Because the
crosstalk between very good cables is so low, you may find that the
effective crosstalk between signals on the two cables is totally dictated by
what is happening at the cable ends (e.g., connection to a PCB where the
signal is not totally enclosed by ground).
If the cables you are interested in are not as high a quality (e.g., thinner
ground shield with a looser braid, etc.), it may be even easier to measure
the crosstalk, but it seems it would still be difficult to predict. Can you
give some more information on the type of cables you are interested in, the
approximate level of crosstalk you care about, and the frequencies of
interest? Our limited experience here in the lab was with good quality
flexible cables with SMA or 3.5mm connectors, looking at frequencies of a
few hundred MHz to a few GHz, lookinf for crosstalk at the ~-100 dB level.
Some cable manufacturers specify crosstalk per foot or some such thing
(assuming some cable separation I suppose). I think I've seen this for RG-6
cable before.
- Erik
==================================================================
Erik Daniel, Ph.D. Voice: (507) 538-5461
Mayo Foundation Fax: (507) 284-9171
200 First Street SW E-mail: daniel.erik@xxxxxxxx
Rochester, MN 55905 Web: www.mayo.edu/sppdg/
==================================================================
> -----Original Message-----
> From: C Deibele [mailto:deibele@xxxxxxx]
> Sent: Saturday, February 02, 2002 4:37 PM
> To: si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Coaxial Cable crosstalk
>
>
>
> Hi again,
>
> I am still working on the crosstalk issue, and I am trying to
> understand even
> an easier geometry.
>
> But the math doesn't seem so nice either.
>
> Does anyone have any rule of thumb for estimating what the
> crosstalk is
> between two coaxial cables? I don't have a nice setup for
> measuring it - so
> how does one design a set of cables based upon a crosstalk criteria?
>
> I must be doing something wrong, because this looks really difficult.
>
> -Craig
>
> ------------------------------------------------------------------
> 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 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
>
>
------------------------------------------------------------------
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 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
Other related posts:
