Can splitters overheat?

Reply

  #1  
Old 09-17-10, 10:44 AM
Gunguy45's Avatar
Super Moderator
Thread Starter
Join Date: Dec 2007
Location: USA
Posts: 21,107
Received 0 Votes on 0 Posts
Can splitters overheat?

OK..it's basically a cable TV kind of issue..but it affects my Internet more..so.....

I have a high quality, wide bandwidth (1Ghz 2 way?) splitter in the office just before it feeds to the cable modem. 1 (labeled OUT) to the modem, one (labeled TAP) to my wifes LCD TV.

We've been having issues where we just lose our connection. Everything seems fine til my wife gets on her PC..then maybe an hour later...we lose the connection. If I remove the splitter and go direct to the modem...it seems to come right back. I can then put the splitter back in (she likes her TV too) and it will work fine from then on.

I had a different splitter in there before (typical...input-2 4db outputs) and when we had this problem I swapped it for the current one. No problem for weeks, at least.

OK I'll fess up...I have pre-made slips fit cables going from splitter to modem..and from splitter to TV. But they don't get moved around and I have tightened them up so they aren't loose. I used 'em cause I ran out of compression connectors for the RG-6.

I plan on getting more comp fittings since I have to replace my modem this wknd anyway (DOCSIS 1.0 to 2.0)....but the question remains...can a splitter "overheat" somehow?

Also...since I don't have a signal strength meter to tell..is there any difference between the IN/TAP/OUT type splitter and IN/4db/4db?

Thanks Guys
 
Sponsored Links
  #2  
Old 09-17-10, 10:51 AM
HotxxxxxxxOKC's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Jul 2006
Location: USA
Posts: 8,044
Received 0 Votes on 0 Posts
Cable modems are very sensative. We had similar problems with ours last year with the same type of splitter. We had to remove the splitter from the cable modem and have a direct run from the NIC to the modem. This solved the problem.

The cable guys came out with their fancy diagnostic machine thingy and determined the splitters were dropping the dB.

What brand and model # cable modem do you have? Mine has a built in signal metering menu which can be accessed to determine levels.
 
  #3  
Old 09-17-10, 11:14 AM
Gunguy45's Avatar
Super Moderator
Thread Starter
Join Date: Dec 2007
Location: USA
Posts: 21,107
Received 0 Votes on 0 Posts
Well..like I said..changing modems tomorrow prob...but I'm pretty sure this 15 y/o thing doesn't have that. Toshiba PCX2200 though...since it just popped up in my brain.

I may have to do that direct line later..but the attic is too durn hot to get in it now. Actually...I think the main feed to that room IS off the main split from the NID...but I may have to run another for the TV.

It just gets to me that disco then reco seems to fix it.
 
  #4  
Old 09-17-10, 02:55 PM
Member
Join Date: Apr 2007
Location: Near Buffalo, NY
Posts: 4,239
Received 0 Votes on 0 Posts
For the record, you have a tap, not a splitter. Both can -- and do -- fail. Heat is a cause of failure. Heat and humidity can also cause connectors to fail. As with any electronic device, quality depends on cost. What's the brand name on the splitter? There are a lot of cheapos on the market -- mostly sold at high-volume retail outlets -- that are prone to failure.

A typical crimp connection to RG6 or RG59 has a high-end limit of around 900MHz. The compression connectors will pass well over 2GHz. Slip-ons and screw-ons really shouldn't be used at all. Jus' sayin'.

As you know, a splitter is used when a CATV line needs to feed two devices. A two-way splitter will drop 3.5 dB to each output. Technically, the 3dB drop is a result of splitting the signal in half, and the other .5dB is applied to both because of the insertion loss of the device.

A tap will also introduce a minimum .5 dB of loss between its "in" and "out" ports. The "tap" port attenuates according to the circuitry. I'm guessing that the modem is connected to the "out" and the TV is tapped.

If the modem is that close to the edge, my first thought would be, "is there another splitter upstream?" If so, move the modem connection further upstream.
 
  #5  
Old 09-17-10, 03:23 PM
Gunguy45's Avatar
Super Moderator
Thread Starter
Join Date: Dec 2007
Location: USA
Posts: 21,107
Received 0 Votes on 0 Posts
Thanks Rick....already replaced the cable between the splitter/tap and modem. Turned out I did have some compression fittings hiding in the bottom of the tool box. These connections are sitting on the edge of my wifes desk..not outside or a high heat area (IMO)..so it was messing with me. Yes...TAP is to the TV..OUT is to the modem.

Not sure if I can get further back upstream...IIRC this is a line directly off the splitter at the cable drop. We'll just have to see how it goes. No way I'm going in the 160 degree attic.

I seemed to remember that (back in the day) we used splitters with a TAP output when we were running TV signals to small compartments (single TV) on the ship. Why aren't these commonly available? Wouldn't they make more sense than regular splitters in many situations?
 
  #6  
Old 09-18-10, 06:41 AM
Member
Join Date: Apr 2007
Location: Near Buffalo, NY
Posts: 4,239
Received 0 Votes on 0 Posts
Cable distribution is actually quite a simple system. It uses combinations of "star" and "trunk" cabling methods. From the point of origin, called the Head End, splitters are used to create trunks, which then hit the neighborhoods. As the trunk passes a block of homes, a tap with multiple drops is used to "star" off the tap to each home. Inside the home, splitters are used to distribute the signal to individual rooms.

If one of the taps on the trunk happens to be a school or hospital, the building will have its own head end, and the process starts over starring into closets on each floor, trunking down the hallways, and tapping into the rooms.

The only real engineering challenge is to maintain the power (decibels, or dB) in the signal, because the cable itself attenuates the signal according to the distance it travels. Worse, the attenuation isn't consistent. High frequencies are attenuated more than low frequencies. Maintaining the signal is accomplished by adding amplifiers along the route with built-in high-pass filters that attenuate the low frequencies to match the highs. The overall signal is then increased to where it needs to be.

Most cable systems also require a "return path", which is backfed to the head end. The return path is the frequency band that's below channel 2, roughly 5MHz to 50MHz. The return path is used to provide two-way communication from the set top boxes and modems to the cable company.

Some splitters and taps will have "power pass" to remote-power the amplifiers. This power is removed from the line before it drops into the home so it doesn't damage equipment. Sat dishes require power-pass splitters to power the LNB.

All that said, the answer to your question is ... if your home is wired in a typical configuration, the cable is probably split several times before it hits the last TV. Taps would definitely help to reduce attenuation due to insertion loss at splitters.

However, because the length of runs in a typical home is relatively short, cable loss isn't really an issue. It's much better to pull all lines to a central location and use one splitter. In this case you may need an amplifier before the split to overcome the splitter's insertion loss. A splitter before the amplifier is also a good idea so the modem receives (and transmits) the strongest signal possible.
 
  #7  
Old 09-18-10, 07:08 AM
Gunguy45's Avatar
Super Moderator
Thread Starter
Join Date: Dec 2007
Location: USA
Posts: 21,107
Received 0 Votes on 0 Posts
Actually...I don't have that many connections. There were only 2 (out of 4 available at the drop?) in use when we moved in...and as I said...pretty sure the modem is directly off one of the previously unused..then the tap from there to the TV in the office.

I have one line leading to the big TV and BD player...then one line goes to my bedroom TV and the garage TV just on the other side of the wall. I still have an unused connection on the main splitter outside..but I couldn't easily get a cable to it from inside..and I plan on using that (eventually) for a flatscreen on the porch.

Last time a tech was here for an unrelated thing, he tested my signal strength at the drop and on the output of the splitter....said it was good. So...as long as I don't have a line split 2 or 3 times (which I don't)...my signal should OK.

Sure wish I could just bring my test equipment home overnite from the ship like I used to...lol.

Eliminating that push on pre-made cable may have taken care of my problem...no issues so far...new modem is at the PO waiting for pickup. That will prob create some sort of issue itself.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: