• Guest, The rules for the P & N subforum have been updated to prohibit "ad hominem" or personal attacks against other posters. See the full details in the post "Politics and News Rules & Guidelines."

Why are there two 6db attenuators from the cable going into my cable modem?

nobb

Senior member
May 22, 2005
237
0
0
Hey.

I hope this is the right forum...but I am curious. I just got cable internet installed. In the back of the cable modem where the coax from the wall plugs in...the cable installer added two FAM-6HR attenuators inline with the cable before plugging it into the wall. So here is what it looks like: coax cable > FAM-6HR > FAM-6HR > cable modem.

My question is...what is the purpose of these attenuators? I tried removing them, plugging my cable directly into the modem and my internet still works.
 

TVisitor

Member
Jun 4, 2007
84
1
0
You could always try to check out the built in status page in the modem and see what your signal levels are. Perhaps the installer checked them and found that the signal was too hot without the attenuators, and installed them to cut back.
 
  • Like
Reactions: DaaQ

ScottMac

Moderator<br>Networking<br>Elite member
Mar 19, 2001
5,471
2
0
That will permit you to put in splitters at a later date without having to tweak the system.

A four-way will drop your signal ~6db. If you split, remove one of the attenuators


Good Luck

SCott
 
  • Like
Reactions: killster1

Paperdoc

Golden Member
Aug 17, 2006
1,857
95
91
Lucky you to have cable signals so strong they have to knock them down a bit!

Are you sure they are simply broad-band attentuators? Could they actually be bandpass filters designed to remove the cable TV signals and allow mainly the data bands through?

On my cable modem system, I've been told the download band is around 850 MHz among the high-channel signals, and the upload band is below 50 MHz where TV signals are absent. I don't know if there could be some advantage to cable modem operation if a filter were in the line to block out signals in a band, say, from 60 to 600 MHz.
 
  • Like
Reactions: killster1

nobb

Senior member
May 22, 2005
237
0
0
I am guessing my cable signals are "so strong" because my entire house is "smart wired." Thats what the builder said, but I am not entirely sure what that means. I do have some sort of distribution box in my basement which amplifies my cable and telephone signals before distributing it to the entire house.

I couldnt find any sort of data sheets on the attenuators, but it would make sense that they are some sort of bandpass filter because my cable tv gets fuzzier with the addition of them. However, in terms of performance boost for my cable modem, I do not notice anything. Ive run speedtests and ping tests, but there is no measureable difference in performance.
 

spidey07

No Lifer
Aug 4, 2000
65,481
3
76
Because your signal is too hot. Too high on the channels used for your cable modem. More does not equal better, signal to noise ratio does.

Much better to attentuate a high level than amplify a low one. It has nothing to do with your house and the BS your builder gave you. Well actually it does because they added an amplifier, hence the need for attentuation.

The amplifiers you have in your house are most likely the cause of your problems. The cable tech just did his best to fix a fubarred home wiring.
 

Noubourne

Senior member
Dec 15, 2003
751
0
76
You should leave them on. If the signal is too strong, it can overpower the reverse, and knock you offline. There is a sweet spot in signal strength that the technicians are shooting for, and the attenuators are probably putting you in it.

Cable modems can be very forgiving when some signals go out of spec, but that doesn't mean that you wouldn't eventually run into problems. I would leave them on.
 

RedB@nkReb3l

Junior Member
Oct 15, 2020
2
0
6
As many people have said earlier it was most likely to control the over hot signals out of the coaxial into your modem one on the feed line from the junction box on a splitter would be so who ever shares the signals with you can reliably connect at decent speeds even if other people were connected. This is just my interpretation of the several technical guides I browsed after the Comcast tech worked on our service. I had to replace an old modem and although I will have to upgrade our router next paycheck since it laughably only has a 2.4 GHz signal. Hey don't judge Lol I bought it in 2010 and it still works..... well I hardwire my PC so yeah it works for other people. heh heh
This is a basic forum to read https://www.speedguide.net/faq/what-is-a-cable-attenuator-488
This is pretty in-depth but I liked learning about it. https://infinity-cable-products.com/blogs/performance/attenuation-in-cable
 

ASK THE COMMUNITY