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Posted by
Recognized Contributor
Member Since: ‎10-23-2003
Posts: 194

Three-Way Splitter = Bad Idea?

I have both HDTV and HSI with Comcast.

 

I split the incoming signal two ways, with one wire going to my set-top box and the other going to my cable modem. This arrangement seems to be working very well.

 

Now I'm thinking of going for broke and splitting the signal three ways, with the third wire going to the RF connector on my television. This would allow me to have picture-in-picture with the unencrypted (basically, local) channels.

 

Is this a bad idea - will I degrade the signal too much by splitting it three ways? The alternative would be to buy a simple antenna and attach that to my television's RF connector, but there's no way of knowing in advance what kind of reception I'll get.

Posted by
Cable Expert
Member Since: ‎03-02-2007
Posts: 13,706

Re: Three-Way Splitter = Bad Idea?

There is no way to tell if switching to a three-way will hurt your signal until you try it, unless it's checked with a signal level meter.

 

What you do want to look for is a balanced 3-way which has equal loss at all 3 ports, which would be -5.5db loss.  A 2-way is -3.5db at each port.

 

The other type of 3-way is a unbalanced splitter which has -3.5db loss at one port, and -7db loss at  the other two ports.  The unbalanced splittters are really like adding a 2-way behind another 2-way.

 

So going to a balanced splitter would only cause 2db more loss at each port, where using a unbalanced 3-way would cause another -3.5db loss at two of the ports, and loss at the third port would be the same as you have now.

 

If you want to search out a balanced 3-way, look for something similar to these that Comcast uses and approves.  LINK

 

Going to the local Comcast office might only get you another 2-way splitter, where flagging down & asking a Comcast tech would most likely get you a balanced 3-way splitter.

 

Your signal level might very well be strong enough for the loss of the extra ports, and either adding another 2-way behind one of the legs of the existing 2-way might work out.

 

Any more on this, please ask.

Posted by
Recognized Contributor
Member Since: ‎10-23-2003
Posts: 194

Re: Three-Way Splitter = Bad Idea?

Thanks for your help. Unfortunately, I'm not knowledgable enough to know whether an extra 2db of loss from a balanced three-way splitter (5.5db vs. 3.5db) would make any difference in my case. Thus far (with a two-way) I seem to be having trouble whatsoever.

 

Would it be helpful if I measured my existing signal strength and reported the results? I think I can do this from the interface of my Motorola cable modem.

 

On the other hand, considering how little a good quality splitter costs - at Monoprice - I suppose I could just try it and see what happens.

 

 

Posted by
Cable Expert
Member Since: ‎03-02-2007
Posts: 13,706

Re: Three-Way Splitter = Bad Idea?

2db usually doesn't do much, as if your that close to the edge you will already have some erratic issues.

 

I would only recommend Comcast approved splitters that meet all specs including EMI from Mfr's such as Regal, Antronix, Commscope, Holland and Extreme Broadband.

 

Your source has not proved to me that what they offer meets the specs needed for a modern digital cable system.

 

Hit up a Comcast tech for the proper part.

Posted by
Recognized Contributor
Member Since: ‎10-23-2003
Posts: 194

Re: Three-Way Splitter = Bad Idea?

Okay. I'll talk to Comcast. In my area (Boston) I usually find knowledgable Comcast reps at Best Buy. Thanks again.

Posted by
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Member Since: ‎05-13-2011
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Re: Three-Way Splitter = Bad Idea?

You will be fine.  I am a tech in VA and our specs for modem is +8 to -8 so as long as you use the -3.5db side for the modem.  That way it will not change your signal for modem.  Comcast doen't provide us with 3-ways no more so to hook up a modem and 2 tv we use a 2-way to a 4-way.  Hope this helps.

Posted by
Email Expert
Member Since: ‎05-21-2006
Posts: 29,136

Re: Three-Way Splitter = Bad Idea?

Posted by
Connection Expert
Member Since: ‎12-24-2003
Posts: 46,868

Re: Three-Way Splitter = Bad Idea?

[ Edited ]

TechinVA wrote:

 so as long as you use the -3.5db side for the modem.  That way it will not change your signal for modem.


Sure it will. It will technically drop the forward and raise the return by 3.5dB but if the stats are adequate in the first place, it won't matter.
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