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Regular Contributor
Posts: 61
Registered: ‎11-10-2006

Another "Do I Need a New Modem" Question

Last April I received an Email from Comcast saying they’ve increased their download speeds up to 25 Mbps and upload speeds up to 5 Mbps and suggesting I need a DOCSYS 3.0 modem to take advantage of the speed increase.  My current modem is a DOCSYS 2.0 Motorola SBS5120 SURFboard and gives me 20 Mbps download and 5.5 upload speeds.  However, occasionally a signal drop requires me to reset the modem in order to restore it.  (I don’t know if this is a modem or router issue.)  Is it possible a DOCSYS 3.0 modem would fix my dropped signal issue, or should I just keep my DOCSYS 2.0 one

Connection Expert
EG
Posts: 41,850
Registered: ‎12-24-2003

Re: Another "Do I Need a New Modem" Question

What do the modem's signal stats look like ? Get them here; http://192.168.100.1

Please post the *Downstream Power Level*, the *Upstream Power Level*, and the *SNR* (Signal to Noise Ratio) numbers.


Regular Contributor
Posts: 61
Registered: ‎11-10-2006

Re: Another "Do I Need a New Modem" Question

Downstream Power Level...   -2 dBmV

 

Upstream Power Level...  52 dBmV

 

SNR...  36 dB

 

 

Connection Expert
EG
Posts: 41,850
Registered: ‎12-24-2003

Re: Another "Do I Need a New Modem" Question

With the upstream power that high you'll likely get disconnections no matter what modem is used. That said, here is my standard spiel of things you can try;

 

The upstream power is borderline / too high and may be intermittently fluctuating even higher out of spec.That will cause random disconnects and spontaneous re-booting of the modem. In an effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured ? Any splitters that remain should be high quality and cable rated for 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, etc. 

 

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.

Regular Contributor
Posts: 61
Registered: ‎11-10-2006

Re: Another "Do I Need a New Modem" Question

There are 2 two way splitters, both from Comcast.  Originally there was only one, and it fed two TVs.  When I switched from dial up to broadband Comcast sent me an installation kit with an additional  cable, splitter and instructions to connect it to the original one and feed the modem and one of the TVs out of the new one.  I can switch them around so the modem feeds from the original one and both TVs come out of the second one and see if that helps.  But I just painted the floor there today so I will have to wait for it to dry first.  Or would it be better to just buy a 3 way splitter? Where would you suggest I get one?

 

There is one piece of non-Comcast cable in the route.  When I bought a new desk last year the origianl Comcast cable wasn't long to put the modem where I wanted to relocate it, so I bought a short coax extension from Radio Shack. Would this make any idfference? 

Bronze Problem Solver
barbie123
Posts: 3,679
Registered: ‎10-18-2008

Re: Another "Do I Need a New Modem" Question

Use 1 two way splitter first. One leg of the splitter should go to the modem. The other leg should go to everything else. Split that leg if you have to.

Connection Expert
EG
Posts: 41,850
Registered: ‎12-24-2003

Re: Another "Do I Need a New Modem" Question

Couldn't agree more with barbie123 !

Regular Contributor
Posts: 61
Registered: ‎11-10-2006

Re: Another "Do I Need a New Modem" Question

OK, I'll switch the connections after the paint drys on the floor.  Thanks.

Regular Contributor
Posts: 61
Registered: ‎11-10-2006

Re: Another "Do I Need a New Modem" Question

OK, the floor is dry and I switched the conncetions.  It makes no difference.  But in checking the forum more I see I am not the only one with the problem.  It abounds with threads about connectivity interuptions and drops.  All this leads conclude that the problem probably is not at my end.

Connection Expert
EG
Posts: 41,850
Registered: ‎12-24-2003

Re: Another "Do I Need a New Modem" Question

Then you need a tech.