• What are the most common types of CATV wiring?
• Anatomy of a CATV Wire.
• Does the quality of the line for digital cable have to be better than analog?
• Will old wiring in my house cause problems with the new wiring?
• Why does my CATV co. need to install new cable for internet?
• I want use RG11 from my modem to the wall, will this be better than RG6?
• Chart of Signal Loss per 100ft
• What about connectors?
• Should flat coaxial designed for going through windows be avoided?

• you can buy rg11 cable fairly readily from electrical and low voltage distributors such as Anixter or Graybar - lookup a local office and walk in and buy it 'over the counter'. I don't use anything but rg11 in my home - yes thicker cable, meaning a larger bend radius and harder to properly terminate but much better grade of cable.

  2016-08-26 16:19:07

by Raydr edited by ergibbs
last modified: 2003-07-10 06:35:29

All conductors lose a certain amount of signal over distance. The "bigger" a conductor is, the less signal is lost over distance (you'll see why this is important later).

Also, dual/quad shield refers to how many layers of "shielding", or layers of "silver metal", cover the dielectric.

The dielectric is next, which is the opaque, white, waxy part of the cable. This is insulation from shielding.

The shielding is the layer of braided wire. The purpose of the shielding is just that. It shields the conductor from stray "outside" signals, also known as ingress (more on ingress later). It also keeps the signal being carried along the conductor INSIDE the cable (prevents egress, which is signal leaking OUT). Most RG6 has 2 layers of shielding (dual), but you can also find quad-shield (4 layers) cable out there. It is more expensive, and harder to work with.

The last layer, of course, is the rubber. This is just more insulation and there's no point in trying to describe what IT does.

Regular Coax Cable:


Dual-Shield Coax Cable:


Quad-Shield Coax Cable:


These pictures and more information on different types of coax can be found at:
http://www.smartwire.com/

• Many CATV coax use copper-covered-steel as the center conductor and shield for reasons of strength when used to span from telephone pole to house - as well as to curb cost. Solid copper center and tinned copper shield can provide much less loss on the signal than steel. What the coax is made of can actually be far more important than the number of shields.

  2016-05-09 09:57:34

• Regular cable has an aluminum foil tape applied over the dielectric then the braid, Tri-shield(not dual shield) has a foil tape over dielectric then a braided shield and then another foil wrap and the Quad-Shield looks good.

  2012-09-07 08:21:30

• ""The caps are a good thing, but most of the cable used is 75 ohm cable so you would need a 75 ohm cap or it will cause an impedance mismatch which can cause you problems."" very important quote, open ports will cause pop outs, from the pole to behind the tv. EVERYTHING MUST BE TIGHT

  2012-01-19 13:17:19 (drcable )

• The caps are a good thing, but most of the cable used is 75 ohm cable so you would need a 75 ohm cap or it will cause an impedance mismatch which can cause you problems.

  2011-09-11 20:15:42

• 4 12 11 Couple things. Yhe coax cable is actually a wave guide. At high frequency, somethink called the skin effect takes over in the wave propagation and the electrons only travel on the surface of the conductor and not in it so a center conductor diameter becomes irrelavant and thinks like quad shielding' proper line tremination, and not exceeding maximun cablle bend raduis wil produce faster, cleaner, less distorted, wavefroms, ie your signal. Also if use have splitters with unused connections, buy 50 ohm terminator caps at an electronics store for them. The center conductor diameter and legnth should insure a good electro/mechanicl joint at the connector mating. Also the materal with the highest electryon mobility, ie GOLD is the highest. So a gold plated copper center conductor would produce the best results. Or so they say. Neet trick. Apply (Fill ) the connector connections with de-electric grease. You get "0" corrsion, for many, years. Also works for aluminum flash lights(no more battery electrolisys, turn signal bulbs, etc. I've pulled apart these items 5, and 10 years later. Still like brand new. Bla, Bla, bla MichaelJoBillyJimBob.

  2011-04-12 15:03:53 (mvallino )

by Raydr
last modified: 2002-03-01 09:21:39

• All signals coming in are NOT analog. Analog signals appear as a sine wave whereas digital signals are a square wave. (High or low, no in between). All of the signals coming in are RF, but RF can be analog or digital, depending on the application.

  2014-11-10 09:19:24

• The thing about digital vs. analog loss: analog signals will get progressively worse on a slope as they lose signal - you will get a worse & worse picture as falloff increases. With digital, the impact is not noticeable at first, because the signal is carrying instructions for the digital set top, as opposed to actual video. So, it can tolerate loss up to a point - and when you reach that point, the failure is abrupt. That's why, when you lose signal in a digital set, the entire picture cuts in and out. In a nutshell, either you get a picture, or you don't. There's very little in-between.

  2013-08-23 03:41:23

• All Signals coming in from a cable are analog. The digital boxes can take the various frquencies and rebuild a digital signal. You loose signal by limiting the strength of the frequencies getting through so that a digital code cannot be rebuilt.

  2012-02-17 20:24:41

• Yes, but what is the difference between analog and digital? Aren't all the signals in broadband analog?

  2011-03-12 05:51:10

by Raydr
last modified: 2002-03-15 09:11:00

• If your old wire from the ground block is feeding the main splitter(s) in the house, maybe into an attic or basement, then the answer to the question is YES, especially if its an old 59 cable or has kinks in it and so on...

  2008-12-06 04:12:35

• Ok... This is the basics and it is somewhat Case specific. I live in a pretty large apartment building. I also used to work for a cable provider so have a bit more hands on knowledge. I use an amplifier on my cable internet connection and have for roughly 3 years now. There are some specifics in my case that very well may not apply to most. I am in a very large building (over 600 units total) (and thats just in my building which there 4 more 3 to 4 floors each depending). My amplifier is on the main incoming Coaxial. Then split on a three way splitter with my cable modem on the -3.5 connection TV's on the -7's. So that takes out a lot of the overhead interference. My cable modem works fine my internet connection work fine and I have used this setup for many years. So you can try it however, it will be a waste if there is not enough distance and splits between the modem and the amp. Also best to split the connection with the lowest negative number line straight to the modem. If you need more than 3 use a 2 way splitter then a 3-5 way splitter on the second coaxial out to the TV's (the lowest negative connection alway goes directly to the modem). Now if you don't have low incoming bandwidth this will not apply if you incoming is high and you amplify it, the splits then need to come after the amp. I would say negative seven straight to modem and negative 3.5 to -7 to another splitter for TV's. That should control the amperage slightly. However if you have high incoming bandwidth and/or there is another issue it will be a waste of money. You can also check the Coaxial wiring in your house, as sometimes pretty commonly your coaxial house wiring is old. This can be very specific as well in an older wiring scheme your splitters may not accept the bandwidth signal ratio your provider uses(This is VERY VERY common). Even if your splitters are good your Coaxial cable may be old. Or the line in may be old anywhere in between the line in within your house may have a single low bandwidth wire or splitter. These thing will definitely effect your connection. (case in point I once installed cable in a house tv and modem, but modem would lock I ran a new cable into the house to up the bandwidth, did'nt work new incoming splitter's amp and grounding, still did'nt work/new run into house to basement where modem was, no go found a single splitter in the roof under tile's in a small room in the basement which had a tan coaxial wire running to it and was also a low bandwidth splitter changed wire to the splitter and the splitter bam cable modem was locked when i got to computer room).

  2007-09-20 10:59:40 (rapid19 )

by Raydr
last modified: 2002-05-12 12:12:43

• It also has to do with the Upstream Transmit level of the modem on the currently installed lines. If you have multiple splitters or numerous live cable outlets in your home, then a new, dedicated line to your modem/emta will be imperative. The reason being is that you have to realize your modem/emta is heavily dependent on two-way communication with the CMTS on the other end of the node. Every split or even a single, 8+ way splitter is going to make it near impossible for your data device to communicate effectively with the CMTS, resulting in frequent dropped internet and/or voice service.

  2012-08-21 23:37:41

• Interesting. That would explain why changing rooms which has a different cable doesn't work even after I ensured the cable box outside was sending the right signal to the right port room.

  2012-07-31 00:11:32

by Raydr
last modified: 2002-08-31 21:49:03

• i agree with the comment, "...it would be an unnecessary waste of wire, room, and money (if it costs). RG11 wire is not very flexible, and a bit thicker than RG6, so it's harder to run as well.", but for the other commentors - you can just put an rg11 connector on the rg11 and it screws onto ANY f-81..

  2011-07-07 19:41:56

• Another reason not to bother: quality of signal is a function of the worst/weakest section of cable. If the entire run isnt higher quality, then only if you KNOW you have the big signal drop due to length of THAT run is it possibly going to help.

  2011-06-15 11:37:08

• Not only is the entire cable much thicker, the F-81s (bulkhead connectors) on the wallplates and CPEs (customer premise equipment) are not built to receive that thick of a center conductor. Connecting a feedthrough style connector where the centerconductor feeds through will result in damage to these interfaces.

  2009-06-11 19:24:09

by Raydr
last modified: 2002-10-24 22:56:04

• Thanks for having this table, but from what I can tell the RG59 column is way high, almost certainly meters, not feet. Comments about variability of vendors are absolutely true, but even more important: all cables degrade with time (particularly in the weather), and old RG-59U is particularly vulnerable.

  2017-11-30 14:09:17

• Yes, RG-59 looks very high, especially for current "quality" cable. Belden provides nominal figures for their "Series 59" broadband coax products at 4.66 db/100' at 400 MHz and 7.68 dB/100' at 1000 MHz. 10*log10(3.28) ~ 5.2 dB More data, including their "Series 6" and "Series 11" cable on page 6.92 of http://www.belden.com/docs/files/upload/06Coaxial_Cables.pdf page 6.92

  2017-09-13 19:18:07 (jef3 )

• There are many brands and quality levels of coax. This generic chart is not true for many coax. Some very cheap RG-6 may be much worse, and some high quality RG-6 may be much better. As 3 dB equals half the power, even small differences in dB loss specifications can have huge impacts.

  2016-05-09 09:52:22

• I think the rg59 column is way off it appears to be for 100 meters not 100ft.

  2014-06-25 05:28:31 (maxbrando )

by Raydr
last modified: 2002-12-15 10:15:35

• For diy without a compression tool i would recommend the new ideal push-on connectors over the old twist ons https://www.youtube.com/watch?v=m1n-j4H3HDM&hd=1

  2014-06-28 00:19:43 (maxbrando )

• Compression fittings are currently the best type on the market. Screw-ons, and crimp-ons allow moisture in the fittings and damage the cable as part of the process of installing them. When I say damage I mean it actually changes the velocity of propagation due to the fact that the "velocity factor mainly depends on the insulating material" which has been crushed by the crimp-on or shredded by the screw-on. I would have to say 90% of outside plant problems are from the drop to the customer premise equipment, and I would have to say 70 - 80% are screw-on and crimp-on fittings. It is these type of fittings that are most often installed incorrectly, induce noise, change the VOP, and allow moisture into the cable.

  2011-09-22 02:22:15

by wmgoat edited by ergibbs
last modified: 2003-09-02 11:45:58

Said by Darkk HERE.

quote:

---

There is no way you're going to avoid an impedance bump with "flat" coax, and that will definitely introduce undesirable effects on the signal in the cable that are detrimental to TV as well as HSI signals. Not to mention that ingress and poor common-mode noise rejection are a problem with this sort of cable.

---

Mainly this sort of cable is very poorly shielded, and should really be used as a last resort.

by Axilla
last modified: 2006-11-03 19:06:00