Outside of my house - where does my signal go?

[Dillinger]

Now love the stuff about the fiber.. would love to know in more detail the infrastracure of fiber network you hasd mention what the node is i woudl love to hear like how its build setp by step form wherever its starting to when is at your house. like where the real fiber starts and where stops and what happens after that.

 

You got it. 

[Dirty Dog]

Yeah, pretty much what Lukasz said.  Maybe do a piece on the Internet backbone? I've heard the term a million times, but have no idea what it is.  

 

And what about the mysterious cable that links the UK to the US?

[Netduma Crossy]

And what about the mysterious cable that links the UK to the US?

 

Yeah, that would be interesting. It's kind of amazing to know that you can ping a server in the US (from the UK) and receive a response back within a ~10th of a second.

[Dillinger]

 

Yeah, pretty much what Lukasz said.  Maybe do a piece on the Internet backbone? I've heard the term a million times, but have no idea what it is.  

 

And what about the mysterious cable that links the UK to the US?

 

 

And we have officially reached the limits of my tech knowledge....  

 

Sorry boys, I have no "international transmission" experience.  I can safely assume a few things about it, based on experiences where I do have hands on, or eyes on, knowledge, but I honestly can't say for certain.  I would suspect there are a combination of deep ocean, heavily armored and protected lines and there are a combination of burst and standard transmission aerial systems using low and high altitude orbit, geosynchronous located satellites.

 

But, things are about to take a turn for the more technical for those of you interested.  Please feel free to raise a hand if you are an interested party and the next part gets a bit complicated. 

 

Or long winded.... Or just plain boring.      

[Netduma Crossy]

And we have officially reached the limits of my tech knowledge....

 

Sorry boys, I have no "international transmission" experience.  I can safely assume a few things about it, based on experiences where I do have hands on, or eyes on, knowledge, but I honestly can't say for certain.  I would suspect there are a combination of deep ocean, heavily armored and protected lines and there are a combination of burst and standard transmission aerial systems using low and high altitude orbit, geosynchronous located satellites.

 

But, things are about to take a turn for the more technical for those of you interested.  Please feel free to raise a hand if you are an interested party and the next part gets a bit complicated. 

 

Or long winded.... Or just plain boring.      

 

Ah, no worries!

 

I'm interested in the next part

[lukasz]

dude when you finish the whole thing i will print each of it to my self and the put it all together and study it.  grate work

 

P.S  BYe BYE black bird

[Dillinger]

Outside Plant:  The 201 class

Okay kids, buckle up for this one as I take the training wheels off and give you a shove down the driveway. J

 

 

For this section it might help if you think of everything flowing from one source, like the faucet on the side of your house, with the plant (Coax, Phone, and Fiber) acting like your hose.  We will be talking about just one flow of data traffic, from BROADCAST to CUSTOMER.  In the example, the faucet would be the broadcast and the flowers would be the customers. 

We have talked about the different mediums that physically bring signal to your house (coaxial cable, twisted pair/phone, and fiber), but now we are going to expand on their abilities and get our hands a little dirty.

 

The keys to selecting what medium will be used to build the plant for your customers, are dependent on a lot of items you, as the service owner, can’t control.  Examples of these are:

·         Miles of plant in your service area

·         Existing easements you have in place

o   Aerial

o   Underground

·         Easements you have to acquire (which is basically how much $$ are you going to have to give to buy your "Rights" or easements)

o   Aerial

o   Underground

·         Permits to build

o   City/Cities where you want to offer service

o   Counties you have to travel through between cities

o   Rural considerations (how many miles must I build to pass a pay-back number of homes)

 

Without going in a long, drawn out table and math formula, just take confidence that I have done this a time or two and I can assure you, assigning a random budget number before all these costs are in, will be a waste of your time.

 

One of the greatest “failures” of this model was the Tacoma, Washington Public Utility, who in the late 90’s decided to OVERBUILD the entire city with their own fiber/coax hybrid plant to cut out AT&T Cablevision, who later became Comcast.  After selling excess power to California, and a couple of other states, during the energy crisis, the City was flush with a little more than USD $100,000,000.00 (That’s ONE HUNDRED MILLION 1997-ish US DOLLARS)  in “surplus” revenue, so they decided to build themselves their own backbone and call it  Click! Network

 

That is a little about the business side of determining HOW to service your area, but let’s talk about why.

 

All “outside the house” infrastructure, in this aspect as well as power and gas (I worked for them too), fall into a couple of categories.

 

·         Actives - Those devices or components which produce energy in the form of Voltage or Current are called Active Components

·         Passives - Those devices or components which store or maintain Energy in the form of Voltage or Current are known as Passive Components

 

The easy way to think about this, for me, is that an Active always need a power source to work correctly (it needs a few things really, but we will get into that later) and a passive will work if there is power on the line or if there is no power on the line.  (Passives also work backwards, meaning they are intentionally inserted output feeding input, but for different applications we will cover later on).

 

Examples of an Active:  Amplifier, Line Extender, Repeater, EDFA, etc.

 

Examples of a Passive:  Splitter, directional coupler/combiner, taps/ports/home connections, termination panels and connection lugs, etc.

 

Passives usually feed customers.  Actives are in place to combat “Attenuation” and insure everyone gets good performance/signal/low-loss of transmitted data.

So what’s Attenuation and why does it matter?

 

Well, let’s see if I can explain it here in a way that makes sense.

 

Let’s push pause on street view and just think about a single, lone carrier in a world full of time and space.  This next image is a JD Original, so if you want signed copies, you are shi’ite out of luck. J

 

 

This represents (1) analog type signal, at one frequency, with a completely static noise floor.  In essence, this is the perfect world for one analog signal to live in and operate.  The signal has a clear peak, it has no other impediments at that level, and it has a good clearance from that horizontal state on the bottom, which is called the noise floor.

 

The noise floor is defined as (Wiki: In signal theory, the noise floor is the measure of the signal created from the sum of all the noise sources and unwanted signals within a measurement system, where noise is defined as any signal other than the one being monitored.  The noise floor isn’t “bad”, it’s just an unfortunate by-product of the delivery method.  But it does play hell on all those signals you want to broadcast.  (Note: it’s much rougher on analog than it is on digital, which is why digital suddenly got very busy in the 90’s as well). 

 

The difference between the measured peak of the signal, and that flat bottom line called the noise floor, is the "Signal to Noise Ratio" or SNR.  This will come up in a few posts, so don’t worry about catching it all right now.

 

Now that last image represents (1) signal, but the broadcast that comes to you from your cable or satellite provider, is actually hundreds and hundreds of these individual tee-pee shaped units, all along a bottom scroller, run to the right, type of thing.  The further to the right you scroll, the HIGHER the frequency level goes., so if you started at 50Mhz, where this example was, and went to the right to say, 85Mhz, there would be 5 or 8 “channels” in between.  (Again, this is an analog signal for ease of understanding – a real “analog channel” has more components, takes up more space and several other facets to it I haven’t broken down yet).

 

So at 50MHz the signal in the picture is measured at 40dB (decibels), this is a very strong signal.  Now imagine that for every 1,000 feet/metres that you push this signal through one of your mediums (coax, phone, fiber) and away from the source, you lose 1dB.  So at 5,000 feet/metres from the source, you have lost 5dB, so you now have 35dB.  At 10,000 feet/metres, you have lost 10dB, so you have 30db, and on down the line. 

 

The further you go from the source, the weaker the signal strength gets and the CLOSER it gets to that noise floor on the bottom. 

 

Now imagine the same picture as above, but the signal is located at 350MHz in the frequency band.  It’s much further to the right from the 50Mhz signal, and it actually loses about 1.5dB for every 1,000 feet/metres traveled.  So at 5,000, you actually only have 32.5dB and at 10,000 feet/metres, you only have 25dB

Then you have a signal like the one above at 600Mhz and it loses 3dB per 1,000 feet/metres traveled.  And the signals up around 800Mhz lose 5dB for every 1,000.  And so on the further you go OUT in the spectrum (higher in frequency).

 

This is called Attenuation.  The further you go, through any medium, the more signal you lose.  The higher the frequency you push through that medium, you lose even MORE signal going the same distance.   The more signal you lose; the closer you drive that crisp, clean signal down into the messy, problematic noise floor.  (*Note, if you picked up on the fact that the signals in question are ALWAYS going to be slanted, from a high point on the left (lower frequency measured), to a low point on the right (higher frequency measured), you get a gold star for this lesson  )

 

And this is where we begin talking about ACTIVES and PASSIVES in the plant you chose to build with….

[Netduma Crossy]

Another very interesting post Dillinger. That one's going to take a little time to process but once it has I'll probably have some Qs

[Dillinger]

Another very interesting post Dillinger. That one's going to take a little time to process but once it has I'll probably have some Qs

 

If it didn't, I'd know I either found the Chosen One, or I have awoken in the Twilight Zone.   This understanding is after about 15 years of learning it, working it and teaching it to new-up-and-comers looking for a raise.  I have forgotten more than I remember and even then I really only ever knew enough to be slightly dangerous.  

 

Post 'em up and I will do my best to assist.

[fuzzy clam]

That's a ton of info to process.I guess I'll be busy for the next month or so...thanks JD...

[Netduma Fraser]

Great again Dillinger, I think I might make a PDF out of all these when I get a bit of time

[Zennon]

To compress it, signal losses strength over distance (attenuation), thats why fibre uses cabs closer to your home, its like bringing the exchange to your door step so to speak, that is why you can gain much faster speeds.

[lukasz]

To compress it, signal losses strength over distance (attenuation), thats why fibre uses cabs closer to your home, its like bringing the exchange to your door step so to speak, that is why you can gain much faster speeds.

i would add to that that also the biger bandwhit in terms of mhz you use then you lose even more at this smae sistance is that right?

 

Sort of if you had a 1.5 l bottel of water and you make a tiny hole one the bottom the waterr will fly further but the bigger the whole the smaller distance water will trawel right?

[Dillinger]

i would add to that that also the biger bandwhit in terms of mhz you use then you lose even more at this smae sistance is that right?

 

Sort of if you had a 1.5 l bottel of water and you make a tiny hole one the bottom the waterr will fly further but the bigger the whole the smaller distance water will trawel right?

 

I believe you are correct lukasz in your version.  If you have signals at (50, 200, 400 and 800MHz respectively), the signal at 50MHz will lose LESS overall strength versus the signal at 800MHz, when measured over the same distance from the source.  This is attenuation and is inherent with every transmission medium (coax, phone, fiber and even AM/FM and Satelitte signals - the further they go, the weaker they get).

[lukasz]

Yesb i not that stupid after all it makes perfect sens to me because the lover the bandwith the more of of that singnal strenght can go on that particular freqq. On the other hand the more bandtwith same singla have to cover the more it have to spread its strength to do so there fore travels less.

[lukasz]

And thast why the medium is soimprotant. Not only by the facct that it phisacly brings te signal to your doorsteps.

 

I mean in those times in such all connected world you need both very strong signal that can carry trought huge spectrums spetrums and the good medium that will handle such strenghts over such huge spectrum

[lukasz]

Sorry it may be wrong but i just got A Picture of it in my head.

 

So instead of sending a analog singnal on a smal bandwith they use a very strong signal a lot stronger for one person on a huge bandwith to a cernty area and then let people share it until that one to much person sing in and the problems starts.

 

And thats wy fiber its they way to go as it allows you to seng powerfull signals on huge bandtwith.

 

All that stuff about passive and active is there to ensure that incoming signal gets to destination witch is the sharing point as less degradated as possible.

[lukasz]

And just thinking about it now the time factor ties in to this theory beacuse the loger it takes the more degradeted its get so again that reinforces the fiber

[Dillinger]

Easy man, your mind is spinning at an impressive rate, but we might be losing the rest of the class.

 

Let me see if I can clarify a couple of assumptions, but I see I need to get my pencil and graph paper out because I can't find the BIG PICTURES that Double D was looking for.

 

Signal Strength:  The strength of the signal has a minimum and a maximum from the noise floor to allow for good, clean signal.  Too low, close to the noise floor, and you get corruption of the signal being transmitted.  Too high, further from the noise floor, and you get into something called "harmonics", which is a story for a much later day.  But essentially for those that want to read ahead, if your signal is too tall/too strong, it creates images of itself on other portions of the bandwidth and is described as: "all the discrete second & third order inter-modulation distortions (IMD2 & IMD₃) that are produced at a channel or around a carrier when two or more signals are of different frequencies are input to a device or system with non-linearity."

 

Fiber:  Fiber is the current medium that is considered the most viable option, when all the factors are represented evenly.  It may, or may not, be "the best" medium for transmission of data, but it does offer a lot of very interesting possibilities like DVDM.  DVDM, or Dense Wave Digital Multiplexing, is a ridiculous science of dividing a single strand of fiber into several "layers - like on a cake" of different colors from the rainbow spectrum.  In each color "band" you can choose if you want signal to leave you and head out (Broadcast), or leave somewhere else and head back to you (Return Path).  In EACH COLOR BAND, you can transmit gigs and gigs of data per second, which sounds like the PERFECT solution for everyone.  And it would be, if the rest of the plant backbone was able to make use of it.    

[lukasz]

So were all of that assumptions i had actually true

[Dillinger]

So were all of that assumptions i had actually true

 

Some were and some were close. 

 

The total amount of signals on any given medium, don't determine the loss (or attenuation).  The lower frequency signals will always lose less strength then the ones in the higher frequency spectrum.  

 

"And that's why fiber is they way to go as it allows you to send powerful signals on huge bandwidth" <-- Not exactly.  The signal isn't any stronger on Fiber, (within operational standards), but it has the ability to travel a lot further from the source.  If you break that signal out, it doesn't really go any further (within operational standards) once the actives and passives are factored into the mix.  Fiber is cool.   Until you have to work with it. 

 

"All that stuff about passive and active is there to ensure that incoming signal gets to destination which is the sharing point as less degraded as possible" <-- Really close.  I'll most likely be addressing Passives/Actives and how they are used in the next big post.

 

"And just thinking about it now the time factor ties in to this theory beacuse the loger it takes the more degradeted its get so again that reinforces the fiber " <-- Not exactly.  Fiber does transmit at the speed of light (minus about 30% through a medium) and that signal is faster than the same type of signal sent through copper/phone/coax and open air forms like radio and satellite.  However the amount of signal degradation is based on the condition of the plant.  If you send the same signal through 10,000 metres of plant, side by side, and all the plant was in perfect condition, neither final signal would have a significant degradation to quality outside of the loss due to attenuation. 

[lukasz]

Well i will proces those info and come back here soon.

 

Still not bad i think for a guy that comes across those stuff for the first time.

[Dillinger]

Well i will proces those info and come back here soon.

 

Still not bad i think for a guy that comes across those stuff for the first time.

 

Given that it's not your primary language, you might be my best student ever.

[lukasz]

Yebs thats sometimes a obstical but will love to actually get on the job etc with you and see and learn that stuff in really that is the fastes way a learn things.

[procreate]

Given that it's not your primary language, you might be my best student ever.

 

i always read his posts in the voice of Da Ali G.

 

 

 

nice to know being in the 3% means very little. i did get a fresh drop on my line a few trips back from the techs. the other thing with cable if there is a lot of construction around you and more customers coming in i found out is sometimes they dont keep up the signals as well as they should which requires another call. i did have one tech tell me about a single customer who had a grounding issue knock out a whole node.