Cable Splitters and Barrel Connectors

[Alex2507]

You know how 2-way splitters say -4dB and 3 way splitters say -8dB?

I was wondering if barrel connectors also caused a drop in signal strength like that.

That's all.

 

[bandphan]

You know how 2-way splitters say -4dB and 3 way splitters say -8dB?

I was wondering if barrel connectors also caused a drop in signal strength like that.

That's all.

Minuscule <2dB. Same with grounding blocks. Single/double insertion shouldnt reduce signal of more than a percentage. If used outside and of poor quality issues may arise. Multiples can add up of off a single long run.

 

[Alex2507]

Minuscule <2dB. Same with grounding blocks. Single/double insertion shouldnt reduce signal of more than a percentage. If used outside and of poor quality issues may arise. Multiples can add up of off a single long run.

Okay. The reason I ask is that I have a cable going to a 2-way splitter after a 50' run. At the half way point I want to split the signal for a new computer hook up.

I was trying to figure out if I should use a 3 way splitter at the half way point and barrel connectors at the 50' point or just use a 2 way splitter at the 25' point and leave the 2 way alone at the 50' point.

Just the way it adds up it seems like I should avoid the barrel connectors as they just add to the signal loss incurred by using a splitter.

Regarding the splitters I also noticed that the cheapo's say -3.5dB but the more expensive Ideal brand say -4dB. Is it just a more honest rating?

 

[nibhaz]

My high quality Regal splitters state 3.5 db loss on each leg.

If you are going to be doing a tie in for a computer connection I would look into a DC cable tap instead of a splitter. Instead of having a 3.5 loss on each side, they usually have one connection that sees only a 1.5 db loss and the other side sees a 6 db loss. You’d want to use the tap with only 1-1.5 db of loss for your computer connection.

 

[bandphan]

Okay. The reason I ask is that I have a cable going to a 2-way splitter after a 50' run. At the half way point I want to split the signal for a new computer hook up.

I was trying to figure out if I should use a 3 way splitter at the half way point and barrel connectors at the 50' point or just use a 2 way splitter at the 25' point and leave the 2 way alone at the 50' point.

Just the way it adds up it seems like I should avoid the barrel connectors as they just add to the signal loss incurred by using a splitter.

Regarding the splitters I also noticed that the cheapo's say -3.5dB but the more expensive Ideal brand say -4dB. Is it just a more honest rating?

All breaks add resistance resulting in some db loss. I dont use el cheapos. Where is the headend? How many splits there? Id use a tap @ the 25' point.

 

[Alex2507]

Thanks for replying guys. It helped me figure out what to do.

I'm helping some friends redo their basement. Currently they have a 15dB signal booster with two 11dB boost legs. Their HSI is off of a (I think 'Regal') 2 way splitter. The cable going to the splitter is definitely not quad shield but going away it is quad shield but the F connectors are jammed on and held together by duct tape ... no sh!t.

They want to move the modem to a spot where I will put a new cable outlet. I think I am going to put the entire house on one of those +11dB legs and split the other leg with a 2-way for the modem and HD STB with all new quad shield and good compression connectors. I'm not there to fix the world. I just want my stuff right.

Nibhaz you mentioned one of those taps in the PM. I don't think I will need one but will look into them because my fascination with cable is what brought me to AH to begin with. Can you suggest a good power cord?

 

[Alex2507]

All breaks add resistance resulting in some db loss. I dont use el cheapos. Where is the headend? How many splits there? Id use a tap @ the 25' point.

Headend? I think that means where it comes into the house. That would be at the beginning of the 50' at a signal boost box mentioned in the previous post. I sort of outlined a plan in that post and nibhaz mentioned a tap in a PM. Thanks for the link. That's very helpful.

 

[nibhaz]

All breaks add resistance resulting in some db loss. I dont use el cheapos. Where is the headend? How many splits there? Id use a tap @ the 25' point.

Thanks for the link, I was being lazy.

 

[bandphan]

Of course I didnt read past Alex's second replay Tap makes the most sense. Be careful of amplification to the line as attenuation might be needed.

 

[Alex2507]

Thanks for the link, I was being lazy.

Yes, you were.

 

[bandphan]

No

 

[nibhaz]

They want to move the modem to a spot where I will put a new cable outlet. I think I am going to put the entire house on one of those +11dB legs and split the other leg with a 2-way for the modem and HD STB with all new quad shield and good compression connectors. I'm not there to fix the world. I just want my stuff right.

That plan may cause some problems for the internet connection. Most amps are not bi-directional, or if they are bi-directional they have a passive return with up to -8db of loss on the upstream, which is critical for a good internet connection. This is probably why the internet connection is currently split off at the cable entry point. They do make active amps that boost upstream (active return) such as this, but I can’t comment on their effectiveness.

Having good cables and proper crimp connections can go a long way.

 

[Alex2507]

The amp was put in by the cable company and everything works as it is now. It has two legs that put out +11dB. One of those legs feeds the modem after a 2-way split. I am essentially going to keep things exactly the same but with better cable and better connections.

I should go and do this thing now before you two talk me into launching a satellite.

It'll be a while before they actually move the modem over to the new location because of the whole renovation/paint process.

 

[nibhaz]

Just to let you know

The amp was put in by the cable company and everything works as it is now. It has two legs that put out +11dB. One of those legs feeds the modem after a 2-way split. I am essentially going to keep things exactly the same but with better cable and better connections.

Well, you should be fine then

Also Alex, you can use your cable modem’s diagnostics screen to read your downstream and upstream power levels. This screen can usually be accessed by typing this link in your browser: http://192.168.100.1

So if you have a laptop and power source for the modem, you can read the signal levels at various points as you change the wiring configuration.

Ideally you want the modem to see a downstream power level of 0dbfs, but the acceptable range is usually +/- 10dbfs.
On the Upstream, you would generally like to see something below 50dbfs. (The higher the number, the harder the modem is working to communicate back to the CMTS.)

 

[bandphan]

 

[bandphan]

This screen can usually be accessed by typing this link in your browser: http://192.168.100.1

or by manufacture

http://www.answersthatwork.com/Download_Area/ATW_Library/Networking/Network__4-List_of_default_Router_Admin_Passwords_and_IP_addresses.pdf

 

[Alex2507]

Wow ... I'll check this out later. Thanks. I've always wanted to know more about what all goes on with this stuff but for now I gotsta boogie.

 

[highfigh]

You know how 2-way splitters say -4dB and 3 way splitters say -8dB?

I was wondering if barrel connectors also caused a drop in signal strength like that.

That's all.

Barrel connectors are directly connected at each end. Splitters have a small ferrite ring with the wire at the input wrapped around it and the wire to each output also wrapped around it. This acts like a small transformer and the signal loss is due to the outputs not having a direct connection to the input- it's magnetically coupled and that's not as efficient as going direct.

More taps equals more loss. Any unused outputs should have a termination cap- this keeps the signal from bouncing (reflecting) when it reaches an unterminated tap.

If you use a splitter for cable TV, it may have a direct connection, which passes DC and doesn't cause much loss. This is important for using PPV but also helps the data transfer. Cable companies want the modem to get the signal before any amplifiers and splitters because they get fewer service calls when it's done this way.

 

[Alex2507]

They do make active amps that boost upstream (active return) such as this.

They have something similar in place.

Well, you should be fine then

Yesterday I replaced some RG6 wire that had barrel connectors all over the place with a single run of RG6 QS and ran it about 12" away from where the old one was: bundled with a bunch if high voltage Romex. I also replaced a couple of really badly installed F connectors. They were literally held on with duct tape.

They are currently running the modem off of a series of two 2-way splitters. Now that I think about it, they were running the modem off of three 2-way splitters but I eliminated one of them weeks ago.

Today I want to replace some more of their barrel connector spliced RG6 or RG59 with RG6 QS and run a new line to feed the future modem and future HDTV locations. I'm going to have them order this outlet for the HDTV.

This is really the kind of work that I like doing.

 

[MDS]

Remember that every split adds additional loss to the incoming signal level. A 2-way will lose 3.5 dB per leg, a 3-way 7 dB per leg, and a 4-way typically 11 dB per leg. Losses are cummulative as well so one leg of a 2-way connected to the input of a 3-way will lose 3.5+7 = 10.5 db at the output of the 3-way (in other words the same as just using a single 4-way).

You want to minimize splits as much as possible and/or use an amplifier where necessary. Of course it all depends on having the incoming signal level from the cable provider at an appropriate level - which is the cable company's job and they will come out and check things if you ask.

From the description of that bi-directional amplifier link: It is recommend a cable or telephony modem should be placed on a separate network segment from the amplifier as incorrectly amplifying or adding to[sic] great of a signal level may cause damage to the cable or telephony modem.

In general that is true and as a rule of thumb you don't want to amplify the leg going to the modem. My house is wired to a central wiring closet in the master bathroom closet and has eight cable outlets around the house.

I split the incoming feed with a 2-way splitter and one leg goes straight to the jack in my office where the modem resides (and is thus unamplified but loses a tiny 3.5 dB from the split) and the other leg goes into an 8-way 4 dB amplifier which feeds all the other jacks in the house. So basically, the cable jacks lose 3.5 dB from the inital split and then the amplifier adds back 4 dB for an effective 'no-op' - as long as the incoming level from the cable company is sufficient every outlet in the house works fine - and they do.