[mythtv-users] Which Signal Strength/Quality Alternative is best?

[Hika van den Hoven]

Hoi Craig,

Friday, January 20, 2017, 9:56:49 PM, you wrote:

> On Fri, Jan 20, 2017 at 12:57 PM, Gary Buhrmaster <gary.buhrmaster at gmail.com>wrote:

> A couple of quick thoughts:
>  
>  First, be aware that no consumer device is calibrated,
>  so the readings are perhaps "in the ballpark", but not
>  accurate.  If you want accurate readings, you need to
>  use a (calibrated) meter.
>  
>  As I recall, the specifications require the devices to
>  support roughly -12 to +15 dBmV ("ideal" is 0dBmV),
>  and to decode 256QAM at a CNR of at least 33
>  (there is no limit, but in practice you do not see
>  numbers more than around low 40's except in
>  very tight plants).
>  
>  It is *strongly* recommended in practice to avoid
>  being near the edge ranges of any of those numbers
>  because real world plants have some variance
>  (a few dBmV changes across the year is not unheard
>  of).  And since you are using consumer equipment to
>  measure, it is even more important to stay well
>  within the middle of the ranges.
>  
>  A high quality amp, and/or a high quality splitter
>  (with appropriate cabling and connectors) should
>  really not be introducing ~2dB SNR noise. And a
>  high quality splitter is usually closer to -3.5dB
>  than a 4.7dB loss.  Whether is is an artifact of the
>  measurement or the splitter/amp/cables is unknown.
>  Something feels wrong there.


>  
> Gary,


> My EE experience hasn't been near RF in decades, so it's all rusty,
> but yeah I agree with all you had to say.  I just don't have
> anything better than the data the Ceton provides.  I guess I'll try
> the splitter for now and maybe see if one from a Comcast customer service office is any better.

> Most welcome would be the suggestion of a suitable amplifier (with
> or without a splitter incorporated) to use in place of the dinosaur
> that came from Radio Shack a couple of decades ago. Brand? Model? Vendor?

> --

> Craig.

As I said in your earlier thread I have a Technetix ITV kit solo I
bought from my cable provider and am very satisfied with it. It has
four outputs with different amplifications. I however am in Europe, so
different signals (dvbc). The local radio shop, which is absolutely
not bad, had none suitable. They were all pre-digital.
If your current amp is "a couple of decades" old, it is pre-digital
and will ruin any digital signal!


Tot mails,
  Hika                            mailto:hikavdh at gmail.com

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