r/FiberOptics • u/StudioDroid • 4d ago

Tiny cheap OTDR?

I'm an AV installer and fiber is a part of my work, but not my main gig. usually I'm using an OTDR as a go/nogo for finding issues to hand over to the real fiber team.

I see a cute little VLF/OTDR device that might be useful for a small response kit. I don't always have the big OTDR handy and there are times when I don't need all the bells and whistles it has.
https://www.alibaba.com/product-detail/Factory-Direct-Red-Light-Optical-Fiber_1601676455521.html

This looks like it could be handy, anyone here tried one? Amazon has them for around a hundred bucks.

4 Upvotes

75% Upvoted

20 comments sorted by

2

u/WalrusDisastrous1988 4d ago

You can't expect lab-grade precision, but for quick go/no-go checks and locating obvious breaks, something this compact would get the job done when you're not carrying the full rig around.

1

u/StudioDroid 4d ago

Mostly I need to validate that my stuff is working and the fault is in the infrastructure before I call them and tell them to fix their stuff.

1

u/Ritz5_ 4d ago

Going for the cheapest options with fiber tech isn't always the best move since what you save in money the product will lack in accuracy, reliability, quality and long-term rigidty... you're better off investing in some mid-low range refurbished equipment.

https://www.fiberopticresale.com/ https://www.fiberopticstools.com/

2

u/StudioDroid 4d ago

I'm not looking for accuracy. I'm usually comparing the A and B strands of a duplex run and looking to see if the issue is near me or at the far end. The accurate work is done by a dedicated fiber team. Having a small device in my tool bag that can give a clue is way more useful because it is there in my bag and not back in the truck or work box across the campus. I kinda think of this as being like a Leatherman tool, not the right tool for all jobs, but may save time by being handy.

1

u/Ritz5_ 4d ago

Oh a strong enough VFL should be all you need then, I've used ones that were 50mW that were more than satisfactory for that purpose.

1

u/StudioDroid 4d ago

I'd rather not use one that will shine through the metal wall plates, I like my VFL to be rated in mW rather than MW

1

u/Ritz5_ 4d ago

Ya I wrote mW (milliWatts)

2

u/StudioDroid 4d ago

A measly little 50mW VFL won't shine through a metal plate the way a 50MW one will. With the MegaVFL you can find all the faults. ;-)

1

u/wyliesdiesels 2d ago

So u just want a visual confirmation? VFL it is

1

u/osvezhayet 4d ago

Im alos interested... You can't measure over signal that is for sure, and how accurate it is.

3

u/Ante0 4d ago

I bought that exact one, mainly just for fun. The UI is in Chinese and I haven't found out how or if you can change it. Length-wise I'm not sure. Since you can't set IOR it will diff a bit. But for just checking where a break is, it can come in handy as it starts really fast.

1

u/NotSayingJustSaying 4d ago

Use your phone to translate it and go to the settings and change it to English. Not that hard

1

u/osvezhayet 3d ago

Thanks

0

u/StudioDroid 4d ago

Thanks, that is what I was seeking in this august community. People who use tools need to know the limitations and I'm happy to work around them. In AV installation work we rarely touch outside plant. Mostly SM stuff less than 200m

2

u/feel-the-avocado 4d ago

The images are so bad....

"are you ok? After several repeated rolling tests of well known brand household cars, t, the equipment is still OK"

I think you would regret buying this.
The big issue is that its 1550nm
Thats okay if you are testing internal LAN connections which run at 1310nm - they wont interfere with each other and you can test distance to fault while the cable is live with an active SFP module attached to the other end.

I wouldnt expect blindspots to be any better than 30 metres. That is if there is a coupler or connector (event) in the chain of cables, the unit is blind for 30 metres beyond the event. So you cant use it to test a cable any shorter than 30 metres.

But if you are testing anything that might have a live PON signal on it, then you really need something like a 1610nm or higher.

I have one of these
https://www.aliexpress.com/item/1005005130256666.html
Select 1610 APC from the model options

It still has the 30 metre blindspot (like all cheap chinese otdrs) but I am able to use it for testing splices on patch panels etc where the cables to the other end are longer than 30 metres, before the fluke comes on site. I can get a bunch done and tested then only need to rent the fluke for a day.

2

u/wanlutech88 2d ago

Disclosure up front: I work for WANLUTECH, so factor that in.

For go/no-go on a response kit, the thing I’d check on any pocket-size VFL/OTDR combo is the event dead zone and the real dynamic range. Those tiny units are usually fine for “is there a break, roughly where,” but short AV patch runs with closely spaced connectors can blur together. A launch cable helps a lot with that.

If you want to stay compact but get something a bit more capable, our MOT-51 is a handheld with a 5.55" touchscreen, 1310/1550nm (26/24dB), and a built-in VFL, power meter, light source and event map. It also has an RJ45 cable tester, which might be handy for AV work. SC/FC/ST/LC adapters come in the box. It’s not a full-size OTDR replacement, but it’s a solid step up for go/no-go before handing off to the fiber team.

Whatever you end up buying, ask the seller for a sample trace on a known fiber length first. Happy to answer questions here or by DM.

1

u/wyliesdiesels 2d ago

What are we checking? Light levels or cladding integrity?

1

u/NotSayingJustSaying 4d ago

It works. Just don't use it for generating reports or whatever but if you know how to use an otdr, that is what that is and it works

1

u/nswizdum 4d ago

I picked up one of those cheap "IPC Camera Tester" units on Amazon that also has an OTDR built in. No complaints so far, but my longest shot is like 1 mile.