There was a spacecraft failure caused by a metric/American conversion issue. 

I want to say it was a Mars lander which made it all the way to Mars and then 
crashed.

 

From: AF <af-boun...@af.afmug.com> On Behalf Of ch...@go-mtc.com
Sent: Friday, August 30, 2024 11:14 AM
To: AnimalFarm Microwave Users Group <af@af.afmug.com>
Subject: Re: [AFMUG] fiber patch cables

 

Just went and check myself, it was the field cap that reflected the light.  A 
non reflective coating had worn away and make the reflection come from a point 
1.3mm closer.  In any event it was a measuring instrument error.  Not a metric 
imperial thing.  

 

 

From: ch...@go-mtc.com <mailto:ch...@go-mtc.com>  

Sent: Friday, August 30, 2024 9:11 AM

To: AnimalFarm Microwave Users Group 

Subject: Re: [AFMUG] fiber patch cables

 

It was an error caused by a temporary cap on a rod in the instrumentation error 
on the mirror grinding setup.  The protective cap had a hole in it.  When when 
they went to check the mirror that hole let laser light through rather than 
blocking it telling them to remove the cap and calibrate the machine properly.  
Only about a 1.5mm error but it was bad in terms of wavelengths of light.  The 
guy in charge of grinding that mirror later offed himself.  They skipped double 
checking the focus prior to installation and launch.  Wanted to save time and 
money they said.  They could have caught it.  

 

Best Regards,
Chuck McCown

McCown Technology Corporation 
8401 N Commerce Dr
Lake Point, Utah 84074
801-250-9503 Office
435-830-4306 Cell
www.mccowntech.com <http://www.mccowntech.com> 
www.microtrench.pro <http://www.microtrench.pro> 
www.terabitnetworks.com <http://www.terabitnetworks.com> 

 

From: Ken Hohhof 

Sent: Friday, August 30, 2024 9:02 AM

To: af@af.afmug.com <mailto:af@af.afmug.com>  

Subject: Re: [AFMUG] fiber patch cables

 

Was the Hubbell Telescope screwup related to metric vs 'merican?

---- Original Message ----
From: "Shayne Lebrun" 
Sent: 8/30/2024 9:55:43 AM
To: "AnimalFarm Microwave Users Group" 
Subject: Re: [AFMUG] fiber patch cables

v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* 
{behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} 

Say, did you know that the Apollo Guidance Computer, from the first iteration 
in 1958, did all of it’s internal calculations in metric, then converted to 
imperial for display to the astronauts?

 

So yes, America went to the Moon on metric.

 

Shayne Lebrun  

Senior Systems Analyst



Support: supp...@lakelandnetworks.com <mailto:supp...@lakelandnetworks.com>   
705-640-0556 | TF: 844-444-4249 

Direct: sleb...@lakelandnetworks.com <mailto:sleb...@lakelandnetworks.com>   
705-646-1846 x583 |  <http://www.lakelandnetworks.com/> 
https://www.lakelandnetworks.com/faqs/

 <http://www.lakelandnetworks.com/> Lakeland Networks

 

From: AF <af-boun...@af.afmug.com <mailto:af-boun...@af.afmug.com> > On Behalf 
Of Josh Luthman
Sent: Wednesday, August 28, 2024 9:12 AM
To: AnimalFarm Microwave Users Group <af@af.afmug.com <mailto:af@af.afmug.com> >
Subject: Re: [AFMUG] fiber patch cables

 

' 

 

EXTERNAL Email Disclaimer 

CAUTION: This email originated from outside the organization. Exercise caution 
when clicking on links or opening attachments even if you recognize the sender. 

Totally missed that last part XD

There are two kinds of countries:  those that use the metric system and those 
that have been the moon.

 

On Wed, Aug 28, 2024 at 8:52?AM Ken Hohhof <khoh...@kwom.com 
<mailto:khoh...@kwom.com> > wrote:

Because he used metric, or because he spelled it metre?

---- Original Message ----
From: "Josh Luthman" 
Sent: 8/28/2024 7:40:18 AM
To: "AnimalFarm Microwave Users Group" 
Subject: Re: [AFMUG] fiber patch cables

OK Euro guy...let the American's get the job done.

 

On Tue, Aug 27, 2024 at 11:59?PM Ryan Ray <ryan...@gmail.com 
<mailto:ryan...@gmail.com> > wrote:

We use EXFO otdr's on some spans that are 160km and we can get it down to the 
metre. 

 

On Tue, Aug 27, 2024 at 7:07?PM Josh Luthman <j...@imaginenetworksllc.com 
<mailto:j...@imaginenetworksllc.com> > wrote:

Don't you document where your splices are?  If you see your splices every 33k 
and see it's broken 1 mile from the last splice it should be pretty obvious, no?

 

On Tue, Aug 27, 2024 at 6:26?PM <ch...@go-mtc.com <mailto:ch...@go-mtc.com> > 
wrote:

Magical device called a fusion splicer.  Our reels were typically 33,000’

 

 

From: Josh Luthman 

Sent: Tuesday, August 27, 2024 3:51 PM

To: AnimalFarm Microwave Users Group 

Subject: Re: [AFMUG] fiber patch cables

 

I don't see how you have a 50 mile span.  Even if you get 80k reels that's 15 
miles.

 

On Tue, Aug 27, 2024 at 5:19?PM <ch...@go-mtc.com <mailto:ch...@go-mtc.com> > 
wrote:

When you have spans up to 50-75 miles at times, you have to use longer high 
power pulses.  There is a lot of variability in velocity of propagation, earth 
temperature, splice slack loops, fiber twist.  1 mile error over 50 miles is 
only 2%.  You can easily be off by several thousand feet.  You can’t just go 
dig.  You have to go to the closest splice point and test again, even then if 
you it show the fault 2000 feet away and you dig at 2000 feet you may be off by 
20 feet or more.  I have been doing this for decades.  Takes lots of digging to 
actually find it.  

 

From: Josh Luthman 

Sent: Tuesday, August 27, 2024 3:01 PM

To: AnimalFarm Microwave Users Group 

Subject: Re: [AFMUG] fiber patch cables

 

A mile?!  IDK how that's possible.  Every time we turn a new splitter on the 
sequentials and OTDR are within a few feet - we lose a couple of feet in butt 
splices and our sequentials end up wrong.  Every new reel gets tested on 
delivery and it's right on. 

 

When we had a broken fiber (ants) it was right on the case.  When we had a 
broken fiber (ribbon got knicked with installation) it was between two cases.

 

On Tue, Aug 27, 2024 at 3:48?PM <ch...@go-mtc.com <mailto:ch...@go-mtc.com> > 
wrote:

Wow, sometimes looking for gopher damager over 20 miles I have been off a mile. 
 

 

 

 

From: Josh Luthman 

Sent: Tuesday, August 27, 2024 1:30 PM

To: AnimalFarm Microwave Users Group 

Subject: Re: [AFMUG] fiber patch cables

 

So far every time we've used the OTDR it's been accurate within 1 foot.

 

On Tue, Aug 27, 2024 at 12:55?PM Trey Scarborough <t...@3dsc.co 
<mailto:t...@3dsc.co> > wrote:

The only thing you have to worry about with shorter cables is the reflection. 
In some instances with dirty connector at just the right connector you can get 
reflection back in to the transmitter that can cause errors, the tx to shut 
down or premature failure. This is very uncommon with LR 10G and less optics 
and can be prevented from making sure you have clean connectors. Check the RX 
and TX levels and make sure you don't have excessive loss. With 100G its a 
little different story due to the combined power of multiple channels, but 
still can be prevented by cleaning connectors, but in some instances Ive had to 
use attenuation when mixing different vendor optics.

The using no launch on an OTDR most automatically calibrating OTDRs will work 
without one. Your results can be off though. Most of the lower cost ones are 
also lower powered and have less of an RX sensitivity so they don't suffer as 
much from the reflections interfering when testing. I can test all day long 
with my little otdrs without one, but my long range 200k+ units I have to have 
a minimum of a 1k spool on it or you see ghosts. They will show up as repeating 
events at even intervals. Not something you will see on shorter runs either.

 

On 8/26/24 4:31 PM, Ken Hohhof wrote:

I should note that apparently I used to do this with direct attach cables (DAC) 
but I think that was a pain, one more thing to stock and to bring with for 
projects.  Whereas I’d always have boxes full of SFPs and fiber patch cords.

 

From: AF mailto:af-boun...@af.afmug.com On Behalf Of Josh Luthman
Sent: Monday, August 26, 2024 4:20 PM
To: AnimalFarm Microwave Users Group mailto:af@af.afmug.com
Subject: Re: [AFMUG] fiber patch cables

 

People say you need a launch cable but our cheap china OTDRs have no issues 
seeing the connector at the end of the patch cable and stuff beyond.  I bought 
a big launch cable back in the day and never use it anymore.

 

Might be different with AE?

 

On Mon, Aug 26, 2024 at 5:16?PM <ch...@go-mtc.com <mailto:ch...@go-mtc.com> > 
wrote:

Only minimum length I know of is the OTDR dead zone.  If that is a problem you 
purposely lengthen the cable with a launch cable.  

 

From: Josh Luthman 

Sent: Monday, August 26, 2024 1:59 PM

To: AnimalFarm Microwave Users Group 

Subject: Re: [AFMUG] fiber patch cables

 

Reddit is wrong.  Gasp. 

 

Connectors are loss, there is more loss in either one of the connectors than 
there is the single mode glass.

 

Between a switch/router in a rack what I see all the time is long (like 5/10/15 
feet) cables and then put the slack in a loop along the posts.

 

On Mon, Aug 26, 2024 at 1:19?PM TJ Trout <t...@voltbb.com 
<mailto:t...@voltbb.com> > wrote:

Patchbox makes some great products, their fiber system is pretty slick but 
expensive.  

 

Cable length is irrelevant it's optical budget / Rx signal strength. Normally 
on 2-20k LR optics you are ok with any length cable, 40km+ needs a pad on short 
spans. (Attenuator)

 

On Mon, Aug 26, 2024, 8:29?AM Ken Hohhof <khoh...@kwom.com 
<mailto:khoh...@kwom.com> > wrote:

Is there a minimum length for a single mode fiber patch cable?

 

I have been using 1 meter cables and they are almost always too long, I’m 
talking about going between routers and switches in a rack, stuff like that.  I 
see that FS sells 0.5 meter cables, but I saw somewhere like maybe on Reddit 
someone claiming there was a minimum length.  Given SM fiber and LR optics, I 
don’t see how 0.5 or 1.0 meter would be different they are both essentially 
zero length.

 

Probably there’s some kind of cable tray or cable management solution I could 
be using but I’ve never liked such things. 

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