Re: Fiberprobe PCB bulk order

Hi Mike, all,

> Original Poster: wwl-at-netcomuk.co.uk (Mike Harrison)

> ><<<< The real trick is getting connectors on the cable.  I us ST
>>style connectors (Bayonet) with ceramic ferrules.  These cost
>>about $9 bucks each and you need four.  It also takes
>>considerable "stuff" to put these on the cable)  Howver Digi-
>>Key sells 10 meter dual cables with ceramic conectors
> >already installed for $37.42.  So, I would think the pre-made cables
>>would be the way to go.

> Not necessarily. 'glass' fibre systems are usually designed for long
> runs (100s of metres). When using them for relatively short distances,
> you can usually tolerate the higher losses of less-than-perfect
> termination methods. I have hand-terminated (i.e. no special tools) a
> 100M length of fibre for a digital audio link with no problems. The
> trickiest part is stripping the thin clear plasic coating from the
> inner core without damage, but a sharp knife and several attempts
> generally works.

For our purposes, I think Iīll have to agree with Terry. An audio
hookup is much more tolerant of "failure bits" than measuring a
coil. Itīs pretty much the same as in "audio" vs. "data" CD. An
audio CD can be scratched up and mishandled a LOT before
you will notice any real difference. This is because audio systems
have exceptionally good error correction bits and if a single bit is
"flipped", you will NEVER hear the difference. Audio systems (CD
players) also have a very sharp cut-off, so RF harmonic
interference (i.e: anything much above 22khz) is simply snipped
away.  A data CD, on the other hand, might wreck real havoc if
a bit is "flipped" (from 0 to 1 or vice versa), esp. in an EXE or
COM file. The same holds true for our measurement system.
They (the probes) will be used in an electronics "unfriendly"
environment. Any reduction in dB (signal to noise ratio) might let
you "discover" something (a blip) on your scope, which in reality,
isnīt there. As to $36 (4 connectors) vs. ~$38 for a finished dual
10m cable, I donīt think it is worth the trouble to DIY, even if you
have the cable laying around (i.e.: for free).

Coiler greets from Germany,