Re: Cable length [was: Contact Information for Electronics]

[Gerard Visser <gvisser@indiana.edu>]

Hi Elke, Fernando,
	I am completely fine with this point of view - it simplifies 
everything, one (or maybe two, FDC+CDC) design for the ADC board 
(equalization filter component values), one design of cable assembly to 
order. [By the way I think Joe's statement is right on the mark, that we 
don't want to assemble those connectors ourselves, it is better to have 
that done by a cable assembly vendor]. The only caution is, people 
planning the cable trays need of course to allow space for the extra 
cable - let's be sure not to forget this small point.
	I will carry on assuming now a single cable length for all of FDC, 21 m 
(though we expect actual 16 m according to the table from Tim, it is 
better to do the testing under a worst-case condition). Similarly for 
CDC we expect actual length of 14 m, I suggest that the test cables (for 
chamber/preamp/cable/ADC prototyping) are made with a length of 18 m.
	Thanks,

	Gerard

Elke-Caroline Aschenauer wrote:
> On Tue, 27 Nov 2007, Fernando J. Barbosa wrote:
> 
> Dear all,
> 
> I can only agree with Fernando, to have different cable length for each
> FDC package seems really not a good idea. concerning the same length for
> the fdc and cdc, I would have less strong feelings, but if there are big
> differnences in lenght which would influence the settings for the
> electronics, than we should rethink as it makes to keep track on spreas
> much harder.
> 
> cheers elke
> 
> 
> 
>> Date: Tue, 27 Nov 2007 09:36:31 -0500
>> From: Fernando J. Barbosa <barbosa@jlab.org>
>> To: Gerard Visser <gvisser@indiana.edu>
>> Cc: Tim Whitlatch <whitey@jlab.org>, Joe Beaufait <beaufait@jlab.org>,
>>      FDC email list <halld-tracking-hw@jlab.org>
>> Subject: Re: Cable length  [was: Contact Information for Electronics]
>>
>> Hi Gerard, Tim and Joe
>>
>>     From a cost, manufacturing and installation stand point, let me
>> suggest we keep the lengths the same for each of the CDC and FDC
>> detectors, or maybe both. Different cable lengths also imply different
>> shaping constants and one fADC-125 model/rev would be preferable.
>>
>> Regards,
>> Fernando
>>
>>
>>
>>
>> Gerard Visser wrote:
>>> Hi Tim, Joe,
>>>     Thanks, this is good information - especially that it includes all
>>> the detectors. But I still have the question, what will the range of
>>> cable lengths for FDC and CDC be? The longest FDC cables, according to
>>> this table, are 52 feet. What proportion of the FDC cables have that
>>> length? What is the length of the shortest FDC cable? There is no
>>> electrical reason to match the lengths exactly, but of course this is
>>> an option, if you have tray space for it. Please let me know your
>>> thoughts on these questions... Thanks,
>>>
>>>     Gerard
>>>
>>> Tim Whitlatch wrote:
>>>> I have attached a table we made last year showing the cable lengths.
>>>> These are based on already installed configuration. Joe has added 7' to
>>>> the numbers. This is good since there will be additional length needed
>>>> for installing the FDC and CDC. This of course should be revisited for
>>>> the final assy.
>>>>
>>>> Cheers,
>>>>             Tim
>>>>
>>>> Joe Beaufait wrote:
>>>>> The longest run calculation done on autocad showed 52 ft, I made the
>>>>> test cables 59' or 18 meters. the 3m connectors are difficult and I
>>>>> would suggest sending assemblies out for construction.
>>>>> the cables I delivered today are not guaranteed.
> 
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