[mythtv-users] Best tuner?

[Stephen Worthington]

On Sat, 5 Dec 2020 16:48:30 -0800, you wrote:

>I posted a query a while back asking for advice on which tuner has the 
>best sensitivity and got a lot of "get your antenna/signal up", which I 
>have been working on, and have made significant progress.  I'm limited 
>by trees and covenants that limit my antenna(s) to attic installations, 
>but I'm close.  We have reliable recordings MOST of the time, but there 
>are still periods of drop-out on certain channels in certain weather 
>conditions and I am hoping that my old Dvico Fusion HDTV dual tuner card 
>(CX23885 chip) is not up to the task.
>
>One thing I'm considering is that, being a dual card, maybe it's got a 
>simple splitter that's cutting down the signal.  I'm wondering if a 
>high-sensitivity single tuner unit (card, USB, or network) would be a 
>better choice.  I'm getting enough channels, now, that two tuners is not 
>enough, anyway, so I thought a distribution amp and another tuner for 
>the weaker channels might just get us ready to dump Comcast once and for 
>all!
>
>For experimentation, I would like to have a portable (USB) tuner I can 
>plug into my laptop.  Any recommendations for a sensitive USB tuner?
>
>All recommendations, ideas and advice are appreciated.
>
>Dave D.

Using a distribution amp can be a bit hit and miss.  There are good
and bad ones, and the bad ones introduce significant extra distortion.
Older multituner cards normally just have a splitter on board, so a
two tuner card will have half the signal level at each tuner.  I have
seen four tuner cards with two inputs (each feeding a splitter to two
tuners) and also four tuner cards with four individual inputs.  In
both cases, you still need an external splitter and probably an amp,
depending on your aerial.

The best amps now are the ones built in on the card.  I have two TBS
PCIe cards built this way with the latest chipsets (TBS6909 DVB-S/S2
and TBS6209 DVB-T/T2/C).  They have 8 tuners each and have a low noise
amplifier on card ahead of their 8 way splitter.  They are set up so
that from a single aerial input, they send exactly the same signal
level as the aerial to each of the tuners, and that signal is only
degraded a tiny bit in the process.  So if you want multiple tuners,
that is the sort of tuner to get.  Unfortunately, TBS do not make any
ATSC cards that work like that.  Hauppague may - I do not follow what
the ATSC manufacturers are doing.

If you have marginal signal levels, as you seem to, then it is
probably best to get professional help.  A proper aerial installer
will have modern test equipment that will allow them to not only see
the signal levels, but also any distortion and interference.  That
allows them to work out the best aerial and signal path.  However,
that depends on finding a good installer - there are plenty of cowboys
out there.

As for choosing a more sensitive tuner, that is difficult.  It is rare
for the manufacturers to publish the sensitivity.  Unless you have
several different tuners, it is also pretty difficult for you as an
owner to work out which is more sensitive either.  The better approach
is to not rely on the sensitivity of the tuner, but to use an
amplifier as necessary to boost the signal level so that it is
mid-range of the usual sensitivity of tuners.  In a marginal signal
situation, this approach usually means that you will need to pay
rather more for a good amplifier which is low noise.  The cheap
amplifiers generally introduce significant distortion, but are fine to
use in good signal areas where all you are doing is compensating for
the loss through your splitter(s).  Most of the amplifiers available
to buy off the shelf are the cheap and nasty ones - you generally only
get the good ones from specialised suppliers of the TV installer
industry.