03-08-2015 12:39 PM
I have seen messages in this forum that indicates that the cable connection to tuners cannot be daisey-chained behind a TA as the TA does not pass the entire frequency range. This directs me to ask if a TA can be daisey-chained behind another TA.
If the answer is yes, could you also list the SNR and dBm requirements for the correct operation of a MTR-700? I have not been able to locate this information elsewhere.
Your guideance is appreciated!
03-08-2015 03:30 PM - edited 03-08-2015 03:41 PM
you want to put the tuner on the thru port on the cisco TA's, all that in and out port is a 2 way splitter. it has 3.5 db loss.
Do not use an external splitter.
Why do you want 2? Your Tivo only needs 1, it's a cable modem and handles multiple tuners
03-09-2015 04:09 PM
My question is specifically if the Motorola MTR-700 TA's can be daisey-chained.
My configuration is perhaps a little more complex than the norm and hence signal quality and the number of splitters (external or imbedded) in use is of real concern. This is why I would like to understand if the signal quality requirements of the TA's are different from the tuners themselves.
In my current configuration I have two Ceton tuners and two MTR-700's in the same location. The signal quality is blanced (as much as possible) across all four devices.
I am wonderfing if the TA's might have slightly less stringent requirements for signal quality (when compared with the tuners). *IF* this were the case, then perhaps the TA's might perform just as well if they were behind another splitter and I could consider adding a third tuner.
Does this make sense?
03-09-2015 08:49 PM
I assume you have TWC internet. Copy and paste the modems signal level page and where 's connected in respect to the outside line and the tv's.
What you probably need to do is replace the 2 way splitter with a 3 way equal port splitter. It will have 5 db loss on ech port. Feed each into a TA and then the output of the TA to the individual Ceton. they will have 8.5 db loss
if the modem/ tv splitter is a 2 way, that's an additional 3.5 db of loss making the TA's at -8.5 and the cetons @ -11
hopefully you have downstream levels at the modem of around 0 dB or higher and the upstream is lower than 40 dBmv...
otherwise you're going to need a bidirectional amp on the tv side of the 2 way.
03-11-2015 08:35 AM
It is obvious that you have some experience in the field. Thank you for sharing your experience and suggesting a solution.
However since the current environment is generally working pretty well, I want to fully understand the existing infrastructure before considering or implementing any changes. For me, this “as is” foundation involves not only documenting the various signal levels but also validating how these current levels compare to the defined requirements and/or official TWC (Motorola, Ceton....) recommendations.
Over time, I have queried various TWC technical representatives regarding the correct signal levels for the TA's. As you might imagine, there has been some variance in their responses as they were generally speaking from memory rather than referencing any official documentation. Using their responses, I have been able to develop a generalized ROT (rule of thumb) to define the approximate “suggested” signal levels required by the Motorola MTR-700.
However, since this ROT is imprecise at best (or completely wrong at worst!) I continue to seek an official documented source of this information as well as an official TWC recommendation or guideline. Perhaps some active TWC technical resource visiting this forum can help me with that by providing consistent TWC guidelines or a quote from the Motorola MTR-700 documentation.
Currently, my tuners and TA’s are in a “star” configuration as recommended by TWC under “Tuning Adapter Installation” for “…a computer connected device” at http://www.timewarnercable.com/en/support/tv/topics/cablecard.html . I recognize that the “passthru” configuration that you are suggesting is valid according to Ceton and other documented sources but I prefer to follow the documented TWC recommendation for a couple of reasons:
I hope that this post serves to explain my quandary: Basically, I know that the signal levels reported by the Ceton tuners are good. The signal levels reported by the TA’s seem to be a little high (at least according to the unofficial ROT). However, without an official reference to use as a guide, I am unable to assign any significance to the possibly high levels being reported by the TA’s. Since things are working well, I tend assume that the levels are actually OK.
Without putting an external signal meter on each of the coax drops, I have to assume that the differences that I am seeing is the result of instrumentation & reporting differences between the Ceton tuners and the Motorola TA’s.