[mythtv-users] mythtv-users Digest, Vol 144, Issue 7

[Mark Perkins]

> On 5 Mar 2015, at 11:26 am, "James Linder" <jam at tigger.ws> wrote:
> 
> 
>>> On 5 Mar 2015, at 6:06 am, mythtv-users-request at mythtv.org wrote:
>>> 
>>> I would think ?OK the dongle is broken? except other channels *do* record and restarting backend ?fixes? the issue.
>> 
>> Just to clarify, do other channels, using the same cardid (1)
>> record after the failure?  Or does once the cardid fail, it stays
>> failed, but only for the Science Channel?
>> 
>> And what usb dongle is this exactly?  I do not recall any
>> dual ones other than hybrid analog+digital (which are not
>> exactly dual)
>> 
>> If this is one of the hybrid analog+digital devices, have
>> you configured the inputgroups so prevent use of the
>> (shared) tuner at the same time?
>> 
>> I would not be surprised that there are additional
>> issues (I know of one during initialization) with the
>> hybrid usb dongles that internally share various
>> components, and take time to transition from one
>> type to the other.  The best advice was usually
>> to dedicate any particular device to either analog
>> or digital (it avoided the sharing challenges).  Yes,
>> it should all get fixed.  I am sure the usual answer
>> applies.
> 
> Hauppage NOVA-TD USB Dual Digital Tuner
> 
> http://cplonline.com.au/hauppage-nova-td-usb-dual-digital-tuner-with-mce-remote-novatdusb.htmlgclid=Cj0KEQiA99qnBRDnrYCkt4ClzZABEiQAvqPaLKmOh-iN1LIZe4fzTT2iIQMtEz3IhXbyO7Y5bVs3EdIaAi-x8P8HAQ
> 
> My box with 2 DVICO and a TWINHAM (pci) card was getting the occasional 0 byte recording, was also getting occasional pixelated and squarky recordings despite being in metro Perth with a decent outside antenna 
> http://www.bunnings.com.au/antsig-metro-medium-digital-outdoor-antenna_p4360384
> and no obvious obstructions. 5Km line of sight to the city over the river then a further straight line 10Km to the transmitters. 
> 
> Hence new backend box with USB tuners since the box was a NUC
> 
> The channels that pixelate tune with a signal strength of 25%, the ‘good’ channels tune with 60% both say S/N of cica 2 db.

Please do not reply to digest emails, it destroys the threading.

Where are you getting these figures from?

Rule of thumb is usually that the reporting of these figures by tuners is somewhat arbitrary and in general only useful for comparing against figures from the same tuner over time. But I generally assume any signal strength less than 70% is too low and liable to pixilate at some point.

Having said that - heavily pixilated should not equate to zero byte files either?

I didn't look at your antenna but over those distances and conditions I would have expected far better signal strengths. I understood 2db s/n margin to be very much unacceptably low. Maybe you have damaged or poor quality cable and connections? Does your antenna point in the same direction as your neighbours and have the same polarisation?
> 
> I’ll do more research to see what is the ongoing status, usually the response to a failed-recording is to restart quick before the next recording is due
> 
> OfCourse after days of failed recordings it's purring along with perfect results
> 
> James
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