Re: cable

[Joe Beaufait <beaufait@jlab.org>]

Mike
Gerard was looking to see if we could get a little better dialectic 
without going all the way back to the expense of the halogen free.
the number of the cable is here:
The number ordered was 169-3099-786.
Gerard's email is gvisser@indiana.edu
please give him a buz and see if we can do any better.
thanks
Joe beaufait



Mike Sigmon wrote:
> I am the representative for Spectra Strip. Can you tell me the part number
> involved?
>
> -----Original Message-----
> From: owner-halld-tracking-hw@jlab.org
> [mailto:owner-halld-tracking-hw@jlab.org] On Behalf Of Gerard Visser
> Sent: Thursday, November 29, 2007 4:36 PM
> To: Joe Beaufait
> Cc: FDC email list
> Subject: cable
>
> Hi Joe,
> 	I have been making measurements on the cable sample (the 25-pair
> cable 
> for FDC/CDC readout). Definitely I am coming to the conclusion that it 
> would be _better_ [I don't say it is _necessary_, just better] to have a 
> better quality dieletric in the cable - the current design uses PVC and 
> this has a high dielectric loss and furthermore the loss is 
> significantly temperature dependent. The end result is, it will be 
> rather difficult to cancel the frequency-dependent losses in this cable 
> with a simple analog circuit. Of course, we might consider using digital 
> tail cancellation (which can be adjustable, unlike the analog version), 
> or we might just live with it. I'm not ready to draw any final 
> conclusions on this yet.
> 	But I am at a point where I think it would be worthwhile to make a
> cost 
> comparison between the present cable (our default choice) versus one 
> where the wire pair insulation is a better material. Everything else 
> about the cable can remain as it is, in particular the outer jacket 
> material can certainly remain PVC.
> 	Since you have handled all the recent discussions with Amphenol, it 
> would probably be best if you could make this inquiry.
> 	Specifically, I would like to know whether they can make version of
> the 
> cable with better dielectric on the wire pairs, either FEP or any other 
> material they can recommend. FEP is a far superior dielectric material 
> (loss factor 0.0005 vs. 0.025). There are probably other choices. Their 
> halogen-free cable uses polyolefin, I don't know its dielectric loss 
> factor, probably it is better than PVC though. We would be happy if the 
> dielectric loss is 10X lower than this present PVC cable, and relative 
> temperature dependence no worse than PVC. So, we're asking for a 
> dissipation factor of 0.0025 or better, I think.
> 	If they can make such a cable, of course the question is then how
> does 
> the cost compare? If it doubles the cost I suppose it will be out of the 
> question...
> 	Can you make inquiries? Or if you prefer I ask them directly, let me
>
> know, and tell me who is your technical contact person for the cable.
> 	Thanks,
>
> 	Gerard
>
>
>