(Adrian Young) So, with our
launch compensation set, we’re ready to run a test.
What I’ve got here is a little sacrificial
OTDR port fiber. We’ll talk about that in a moment
and the reason why I’m doing that. I’ve got my launch fiber,
I’ve got my tail fiber, and I’m connected to
my link on the test. And for those of you who saw
that CertiFiber Pro video I did, this is the same fiber that I’m testing. And there’s good reason for doing that,
when I download the results later on. So we’re going to be measuring this
in one direction and in the other direction. And we’re going to be disconnecting
from the OTDR. The reason why I’m using
this 12-inch, 30-centimeter cord, is to protect my OTDR port.
Because when I measure this link in the other direction, I’m going to be
disconnecting from the OTDR port. So by having this little,
short cord on there, this is the cord that gets
changed all the time. It’s certainly a lot easier
to replace this little cord than it is an OTDR port.
Now I can do this because it’s very short and it’s
within the attenuation dead zone of the OTDR port. You can never,
ever put a short cord on the end of your launch fiber to
convert it from one connector to the next. Because if you do that, you’re going to
end up measuring two events as one and potentially failing a link
that should not be failing. So this is okay. But never put this short
cord on the end of the launch fiber. So we’re all set up
and we’re ready to go. And we’ll just make sure
we’re on the “Home” key. We are. Go ahead and tap
“Test” for me, Amanda. When it does the test here,
you’ll see we got our OTDR port connection quality and
you can see our trace is building with our two little spikes,
representing this connection here and this connection here
on our table here. What comes up on the screen first
is EventMap. And on the EventMap here, you’ll notice that we have
3 segments of fiber. The first segment,
which is slightly grayed out, is our launch fiber.
The last segment, which is also slightly grayed out,
is our tail fiber. They’re slightly grayed out.
That tells me that we actually used launch + tail compensation. So
the length reported up here is only the length of the fiber
that we actually measured. Most people doing an OTDR measurement
expect to see an OTDR trace. So go ahead and tap on “Trace” there. And that’s exactly what you get
on this instrument, it is a full-blown, OTDR tester. Now this is what we call “sticky.”
So the next time you go and do a test, you’re not going to see EventMap,
you’re going to see the trace here. And lots of folks like to spend time
analyzing the trace. And again, you can do that with this OTDR.
It even has a pinch and zoom feature. So go ahead and pinch and zoom in
on one of those events. With this kind of phone, you can really do
all the analysis that you want to do. But in reality, most people these days
doing OTDR testing are not testing 12 fibers. They’re testing hundreds,
if not thousands of fibers. And it’s really just not practical to go
through and analyze every trace every time you do a measurement.
And that’s why we created EventMap. Now, if you don’t have an OptiFiber Pro,
what you might do is go to the table. So go ahead and tap on “Table” for me. And that kind of makes it
a little bit simpler. But you’ve still got to read
a whole bunch of numbers. But if we go to “EventMap,” it just makes life so much easier. And the event will also go to the
largest loss event that’s recorded. Now, you’ll see that there’s
another connector there, Amanda. If you want to tap on that
other connector for me, you’ll notice that the box jumps.
And now we’re reporting the loss on the other connector as well. And
that’s something unique to this tester is that you can bop around
the different connections on the link. If you have more than two connections,
maybe ten connections on your link, all ten connections are
going to be reported. Splices are reported as a little
round thing, and the connections are reported as you see
on the screen here. So that’s our measurement done.
It’s saved. But we’ve only done it in one direction.
And well, we haven’t saved it yet. Go ahead and tap “Save” for me. And you’ll notice
in the top right-hand corner here, it says, “N1.”
That’s important to note because we’re testing from
N1 so far. It should say “01A,” which is our cable ID sequence.
So go ahead and hit “Save.” And now it’s saved.
So what we want to do is, you want to make the measurement
in the other direction. So I’m going to disconnect
from my launch fiber here, and I’m going to cap it. Bring it around here. And Amanda’s going to
connect it in the other end and we’re going to measure
this fiber in the other direction. Now before we do that, there is
one other thing we need to do. Go and press the “Home” key
for me and the cable IDs. Remember, we were testing from N1.
We’re not testing from N1 anymore, We’re testing from N2. So go ahead
and move that over to N2. And down here. And so hopefully, on our home
screen now, it should say, “N2 01A.” (Amanda)
Uh-huh [affirm]. (Adrian Young) If you didn’t
change it from N1 to N2, what’s going to happen is,
if you try and save it in 01A again, the tester is going to complain that
you’ve already got that test result. But by swapping this cable ID to N2,
the tester is smart enough to go, “Aha, I know you already have a 01A,
but because you’re telling me it’s from the other end, then that’s okay.”
And it’s going to save that. And it will create one record for that
one fiber, testing in both directions. Go ahead and test now. And again, our OTDR port connection
quality is shown on the screen here. Ah, we have a warning on the screen.
And what is this warning, Amanda? (Amanda) It says, “Negative loss
of gainer, event found.” (Adrian Young) This is not a
familiar term to a lot of OTDR users. So what has actually happened here
is that one of these connections here, we have a slight mismatch in
backscatter coefficient between the fiber that we’re using to test
and the fiber under test. Now normally, that causes some fear.
But that’s not a problem in this instance. And I’ll show you in around why.
So go ahead and tap “Okay” for me. And go and tap the other connector
on the EventMap here. And does it show a
negative loss there? (Amanda)
Yes, -.05. (Adrian Young) Okay, so there’s
our negative loss value. Now, if you get more than -.2 db, you will get a warning
on your test report. Now how do you get rid of
that negative loss warning? The standards recognize that
this can happen. And so what they tell you to do
is to test it in both directions. Now, we’re testing it in both directions. The second part of that equation is,
you then download the results, and you average the directions
that you’re tested in. So in a moment, in the next video,
when we download the test results, we’re going to do the averaging
and that negative number is going to disappear and we’re going
to end up with a positive number. And not only is it going to be positive,
it’s going to be more representative of the loss that’s in that connection. Now, for those who are out there
are listening to this accent, you can probably tell that I’m not
from America, I’m from the U.K. And being from the U.K.,
I’ve set the unit to meters. And I know what you’re thinking,
“I want this in feet.” So Amanda, press the
“Home” key for me. And tap “Tools.” And swipe up to where we see
our feet and meter option. Okay, press the “Home” key. And tap “Unsaved Result.” Now our EventMap is in feet
and everybody can relax. So yes, you can flip this
between feet and meters and you can also do that
in the LinkWare software. We must remember though,
we need to save the result. So go and hit “Save.” There’s my cable ID list,
confirming it’s N2, hit 01A. Go ahead and hit “Save.” And now I completed my OTDR
measurement in both directions. But, before we go off and
download some test results, I am going to cut across
to another setup we’re going to show you what
happens when our link fails. So that was a passing test result. What happens when you
get a failing result? So an example I’ve got on
the table here is there’s a bad splice halfway down the link. And the
nice thing is, with EventMap, it clearly displays where that is. And I can go straight to that location
and figure out what’s going on. On a traditional ODTR,
if you’d like to tap “Trace,” you’re going to have to try
and figure out this trace, pinch and zoom in, and try
and figure out where that event is. But again, if you go and tap “EventMap,”
it just makes life so, so much easier. So that’s an example of
a passing result, an example of a failing result.
In the next video, I’m going to show you how to
download those results, print out those all-important test
reports, and get paid for that job.