[mythtv] Problems with Hauppauge Nova TD Dual Tuner USB Stick and Mythtv, no problems in Windows!

Gary Buhrmaster gary.buhrmaster at gmail.com
Fri Apr 12 16:46:29 UTC 2013


On Fri, Apr 12, 2013 at 1:39 PM, Stephen Worthington
<stephen_agent at jsw.gen.nz> wrote:
...
> As it is a dual tuner, it will need to split the aerial signal to feed
> it to both tuners.  A splitter typically causes around 6 dB of signal
> loss.

As I recall, that would have been more like ~3.5dB (about half
power (which would be 3.0dB), but there are insertion losses too).
One would have to be purchasing very cheap splitters to see a
6dB loss.

> So that means that any dual tuner will be that much less
> sensitive than a single tuner.

With the presumption that the tuner uses only a splitter.
While most low cost devices do (and Hauppauge is a low
cost device), there are alternatives (including using an
internal amp) which can mitigate such issues.

I will point out that whether the splitter is internal or
external, the losses are (approximately) equivalent.
So dual vs. single is not the issue (two singles with
your splitter is no different than a dual with an internal
splitter).  Adequate power level to the tuner is.

Note too that the design of the tuner (whether in a tuner
card/dongle, or a TV) can impact the signal sensitivity.  It
is common in "fringe" areas for one TV to get a subset of
channels that another TV receives fine.  Tuner cards are
no different (which is why the "it works with my TV, why
does my tuner card not see channel X" simply suggests
that the signal may be marginal to begin with).

Unfortunately, to validate the real signal power and quality
requires equipment that few individuals will have access
to.  So most are left to try this, try that, and try the other
thing.

I do agree with Stephens conclusion though, adequate
signal level (with low noise) is the key.

Gary


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