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RG11 Installation Advice Needed

477 Views 4 Replies 3 Participants Last post by  bfoster
A friend of mine lives a distance off the road and wants to get broadband internet service from the local cable company. How far can we run RG11 underground and still maintain enough signal to make the cable modem work properly? He will not be using the cable for any TV service, only for internet.

Thanks, rm6565
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Here is the attenuotion chart for Belden 1523A RG11 cable.

Freq (MHz) Atten(dB/100 ft.)


55 ------------0.97

211------------ 1.81

270 ----------- 2.05

300 ----------- 2.15

350 ----------- 2.32

400 ----------- 2.47

450 ----------- 2.65

550 ----------- 2.94

750 ----------- 3.50

870 ----------- 3.84

1000 ---------- 4.23

Now I am, going to go out an a limb here and say that's probably pretty typical for RG11, I am sure there are better and worse types of cable out there.

This also brings up a few more questions.

1) What frequency range is broadband internet on?

I believe the down stream is near the 870-1000Mhz range and the upstream is closer to the 55Mhz area. But don't quote me on that ;)

2) How strong is the cable signal to start with?

I really do not know.

3) What are the signal levels the cable modem needs to operate?

Here is a excerpt from Broadband Reports cabe FAQ:

Q: What kind of signal levels do I want on my cable modem? (#3412)

A: Downstream Power:

You generally want between -12db and +12db. Most modems are rated from -15 to +15. Anything less or more than that and you may have quality issues.

Upstream Power:

The lower this number is, the better. If it is above 55, you may want to see if you can reconfigure your splitters. Anything above 57 is not good and should be fixed ASAP. (This is getting pretty close to not being able to connect.)

4) Will the cable company use your self barried cable?

Good question!
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Cable companies typically will only go up to about 500' with drop cable, some less. Anything over that would require hard line.
The distance will be over 500 feet but I have a plan that has worked before. I hope to run the RG11 to about 400 feet then mount a weather proof enclosure to house the cable modem. The run Cat5 from the cable modem the rest of the distance to a router located in the house. I have done this before and documeted it on my blog. It won't let me post a link on here yet because I am new to this forum. Perhaps I can soon. You might find it interesting.
If you have power available there would be no reason to run RG11. Let the cable co install to a location within their parameters then put in a WAP.
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