Re: oh yeah?

Dave Casey

I'm in the same boat regarding the general unavailability of Diamond 3.5
patch cables. I'm sure they're out there, but nobody knows what they are.
So unless you find some in a bin at a surplus store, they're going to be
hard to come by. It's worth noting that HP used Diamond 2.5 in a few pieces
of gear, but by then it was called "HMS-10" (for single mode, multi mode is
HFS-13). The thread pitch and other dimensions are identical to Diamond
3.5, it's just the ferrule that's different. I've wondered if an HMS-10
cable could be used if one could shim the difference. The Diamond 3.5 is
HMS-0 in single-mode and HFS-3 in multi-mode. Vendors were offering patch
cables with the connectors on them as recently as 2000 per one datasheet
I've found. There's just not enough value in the resale market for them to
come out of the woodwork.

Dave Casey

On Sun, Aug 11, 2019 at 7:32 PM Dennis Tillman W7PF <@Dennis_Tillman_W7PF>

Hi Jim,

I uploaded another screen shot into the album I created last night.
The album is at
The photo is called 7) S-42 Internal Reflections.
It shows what happens to the S-42 internal reflections until they die out
about 1.5nSec after the optical pulse ends.

If you were doing optical work with fibers in the early 1990s you may have
been using Diamond 3.5mm optical connectors like the ones in the 7F10
Optical to Electrical Converter plug-in I have. I would like to be able to
use it but I have not been able to find that connector anywhere nor have I
found an adapter that would allow me to use a more common fiber optic
connector so I could plug the newer connector in one end of the optical
adapter cable and plug the other end of the optical adapter cable into the
7F10. That would allow me to use the 7F10 without trying to change the
Diamond 3.5mm connector.
Dennis Tillman W7PF

-----Original Message-----
From: [] On Behalf Of Jim
Sent: Sunday, August 11, 2019 2:01 PM

Dennis, it looks like the S-42 has a bit of reflections inside it. The
OIG-502 uses an ingenious scheme to avoid generating them at the source;
the laser diode is biased such that any current reflections on its input
due to imperfections in the termination are below the LD threshold
current. LD physics is such that the current reflections have no effeffect
on the optical output. Voila, reflection-free optical impulses! I assume
a brilliant engineer at Tek came up with that; correct me if I'm wrong. I
had one back in the mid 1990's at Lockheed Aircraft Service Co., housed in
a TM502 mainframe (the TM501 was unavailable at the time, IIRC).Jim Ford

Dennis Tillman W7PF
TekScopes Moderator

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