[RichO]

I have a quick question about TV signal splitters. I am using OTA for all my TiVo channels now and when the cable guy installed the wires he put on a 2-way splitter. Each output was labeled as -3.5dB. I needed to add a third TV so I used a 3-way splitter I had laying around. The outputs on that one are 2 of them at 7dB and one at 3.5dB.

I am puzzled by these numbers. I understand that it has to do with signal loss but why is one different than the other 2 and how does it affect my signal? I did check one TV and some channels do not seem as clear.

Thanks for any help.

 

[Wil]

I have a quick question about TV signal splitters ... The outputs on that one are 2 of them at 7dB and one at 3.5dB

That's a type of tap rather than what is usually referred to as a splitter. If you want equal splitting of a signal, i.e. if all of your lengths from the splitter are approximately the same, you would want a splitter. But if, say, you want to tap off 2 lines then continue your main feed on to tap off one or more later on, the tap you have in hand would be more appropriate.

 

[snerd]

It is an "unbalanced" 3-way splitter. Internally, it is built from two 2-way splitters. The input port connects to the input of the first stage, and one of the outputs of the first stage is connected to the input port of the second stage. Signals passing through both stages have a loss of 7dB while signals passing only through the first stage have a loss of 3.5dB.

The signal from the 3.5dB port will be about twice as strong as the signal from the two 7dB ports.

If you want the same loss on all ports, get a "balanced" splitter which typically has 5.5dB loss on all ports.

 

[RichO]

Well, for the most part, the lengths are the same, give or take 20 feet so I guess I would want an actual splitter with equal dB at each output.

Local stores have a cheap looking splitter that just says IN and OUT OUT OUT with no specs printed on the splitter. It's also only $3 so I can't imagine it's the best quality.

 

[Wil]

Local stores have a cheap looking splitter

There really can be an observable difference in quality correlated to price and brand reputation. But OTOH there used to be a ubiquitous "RCA" branded gold-colored splitter that actually tested out just as well as expensive splitters but I don't know if that's still the case.

 

[RichO]

Yes, it's this one that contains no details about the outputs.

 

[dlfl]

Are there signs the -7 dB signals are degrading reception? If not, don’t worry about it! Tuners have a wide range of acceptable signal strengths. Or if one of the three devices has a weaker tuner, use the -3.5 dB port for it.

 

[RichO]

Are there signs the -7 dB signals are degrading reception? If not, don't worry about it! Tuners have a wide range of acceptable signal strengths. Or if one of the three devices has a weaker tuner, use the -3.5 dB port for it.

Not sure. At times the picture looks a big grainy in HD but not on all channels and I did not compare it to when it was the balanced 2-way splitter

 

[dlfl]

Not sure. At times the picture looks a big grainy in HD but not on all channels and I did not compare it to when it was the balanced 2-way splitter

Not sure what you mean by "grainy" but weak signal usually causes intermittent break-up of the video, often called pixellation, not what I would describe as grainy. Again if one of the sets is worse than the other two, hook it to the -3.5 dB port.

 

[cannonz]

This series clearly explains it. --

 

[RichO]

Not sure what you mean by "grainy" but weak signal usually causes intermittent break-up of the video, often called pixellation, not what I would describe as grainy. Again if one of the sets is worse than the other two, hook it to the -3.5 dB port.

No breakup in the signal, just that I noticed the picture was not as clear as I would expect for HD on some channels, but probably unrelated to the splitter

 

[cannonz]

On my cable some OTA channels are grainy you could call it (looks like VCR) while the same one off antenna is great, I guess they compress it too much.

 

[mblloyd]

Well, for the most part, the lengths are the same, give or take 20 feet so I guess I would want an actual splitter with equal dB at each output.

Local stores have a cheap looking splitter that just says IN and OUT OUT OUT with no specs printed on the splitter. It's also only $3 so I can't imagine it's the best quality.

The difference in price is related to the frequency response of the splitter as well.

 

[snerd]

The difference in price is related to the frequency response of the splitter as well.

Splitters are like cables, priced outrageously from most sources because people just don't know better. monoprice.com is one solution.

 

[RichO]

As a follow up to this question, some strange things are happening, most likely related to the splitter. I have 3 TVs, and a few channels don't tune in on certain ones, while they do on others. Would I just want to go with a balanced splitter, or perhaps a signal amplifier? The TiVo must be picking up signal on certain channels when doing a scan since it adds the channel to the list but there is no picture when trying to tune it in.

The cable runs are in the ballpark of 80' from the splitter, which is about 25' from the antenna in the attic.

 

[JoeKustra]

I hate to ask, but what model TiVo? What signal strength does it show in Diagnostics?

 

[RichO]

OK, some really strange things going on, not sure when it started:

TV #1 - Roamio:
Ch 11.1 - unable to tune in, signal strength peaks around 85
Ch 11.2 - unable to tune in, signal strength peaks around 85
Ch 11.3 - tunes in but displays the programming airing on 11.1
Ch 12.3, 12.4 and 12.5 have signal and tune in but they are clones of 11.1, 11.2 and 11.3 respectively. These channel numbers are not labeled and have no guide info.
Other channels that tune in fine have a peak signal strength in the 70s.

TV #2 - TiVo Premiere
Same issue as with TV #1, but signal strength is low 90s for 11.1 and 11.2. This one is connected to the -3.5 output on the splitter. The other 2 are on the -7 outputs.

TV #3 - Direct connection, no TiVo
All channels tune in just fine. 11.1, 11.2 and 11.3 all have correct shows matching program guide

 

[kpeters59]

No breakup in the signal, just that I noticed the picture was not as clear as I would expect for HD on some channels, but probably unrelated to the splitter

Ch 11.3 - tunes in but displays the programming airing on 11.1

11.1 is likely the only actual HD Channel on all the 11.x channels.. The sub-channels are very typically a much lower bit-rate picture. That would explain why it seems "grainy".

It's not surprising that all the 11.x, 13.x and what-not channels have the same signal levels...they're the same channel, just different sub-channels on the same Carrier.

Did you say where you're located? It sounds like some of this is due to the Channels being re-packed.

You may need to submit a channel lineup issue to TiVo:

Tivo Customer Support Community

-KP

 

[RichO]

11.1 is likely the only actual HD Channel on all the 11.x channels.. The sub-channels are very typically a much lower bit-rate picture. That would explain why it seems "grainy".

It's not surprising that all the 11.x, 13.x and what-not channels have the same signal levels...they're the same channel, just different sub-channels on the same Carrier.

Did you say where you're located? It sounds like some of this is due to the Channels being re-packed.

You may need to submit a channel lineup issue to TiVo:

Tivo Customer Support Community

-KP

Thanks! I just submitted a detailed lineup report. I hope it submitted correctly because when I hit submit, the page cleared and the reloaded with a blank form, no message that the info was received.