[mythtvnz] HD HomeRun vs HVR-2200 for DVB-T?

[Stephen Worthington]

On Sun, 08 Sep 2013 08:00:43 +1200, you wrote:

>On Sat, 07 Sep 2013 23:35:16 +1200, Steven Ellis <steven at openmedia.co.nz>  
>wrote:
>
>> Has anyone here done a comparison on the two devices when dealing with
>> marginal signal issues.
>>
>> My TVNZ and Mediaworks reception is OK but Kordia is a bit marginal on my
>> HVR-2200, but fine on my Samsung TV.
>>
>> Steve
>>
>I'm in a fringe area (50km from the transmitter,no line of sight) and  
>experience occasional pixellation during rain and high winds (mainly due  
>to nearby tree movement).
>Both the HVR-2200 and HDHR are about the same for this and about 80% as  
>stable as my Panasonic TV.
>
>Paul

Does your HDHR have dual tuners?  If so, then like the HVR-2200, the
internal splitter will be dropping the signal level compared to the
direct feed to the TV's single tuner.  The signal levels at all tuners
in multi-tuner devices will always be lower than in single tuner
devices due to that problem.  So you will always get better signal
levels at the tuners if you have one external multiway splitter that
feeds your TV and multiple single tuners than if you have a dual
splitter that feeds one leg to the TV and the other leg to a dual
tuner.  The leg going to the TV is not split.  The leg going to the
dual tuners gets the same signal level as the leg to the TV, but is
then split in half.  This is a fundamental problem with using multiple
tuner devices that catches people all the time - they say their TV has
a better tuner, when the tuners themselves are not to blame, it is
just the level of signal that is getting to them is different.

Which is not to say that there are not tuners out there with different
sensitivities - there are.  But the tuners in TVs almost certainly use
the same chips as the ones in PC tuners - TVs do not have inherently
better tuners.  But all the time there are people posting about
problems where their dual tuner is not picking up the weakest signals
and their TV is, and it is usually just the geometry of the signal
splitting that is causing the problem.  Feed a tuner less than half
the signal level and it will perform worse.

The reason why the Kordia multiplex is the one that usually has
problems is that it is normally the highest frequency multiplex.  Any
fixed aerial system working over a range of frequencies is always
going to perform best at a certain part of that range, with the
performance declining as the frequency of the signal is further away
from that best frequency.  Kordia, at its higher frequency, is usually
the multiplex that is further away from the best frequency and
therefore gets the least signal at the tuners.