[mythtvnz] Reception problems with HVR2200

[John McKnight]

On 10/10/12 00:38, Curtis Walker wrote:

> On 9 October 2012 22:02, John McKnight<mcknight at paradise.net.nz>  wrote:
>> I am running Mythbuntu 12.04, combined frontend-backend, and I can't get
>> reliable reception with an HVR2200. The symptoms are random pixelation in
>> recordings, and when things are really bad, distorted sound.
>> I have a single UHF antenna - line of site to Kaukau from Maungaraki in
>> Lower Hutt. I use an internal splitter to feed the TV and HVR2200.
>> This seems to be a classic case of poor signal at the HVR2200, as bad
>> weather seems to make things worse. However, the TV never - and I mean never
>> ever - has any reception issues whatsoever.
>>
>> I have tried a Kingray internal amplifier replacing the passive splitter -
>> The TV was happy, but Mythtv could not get a lock at all.
>> I have tried swapping flyleads, and replacing the passive splitter - no
>> improvements.
>> I have tried removing the passive splitter and going direct to the HVR2200 -
>> no improvement.
>>
>> I am reluctant to splash out on a new antenna, as I am not certain that
>> there is anything wrong with the existing one, and looking at the archives
>> it seems that other people have had reception issues with HVR2200s in the
>> past. So I am leaning towards trying a different tuner card.
>>
>> Can anyone suggest a tuner card that is not quite as deaf as the HVR2200?
>>
>> Cheers,
>> John.
>>
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> I've got a HVR-2210, which is pretty similar (although slightly less
> mature driver support in linux). I'm having what I 8think* are
> reception problems, in the middle of Hamilton - in sight of the
> Hamilton infill tower, with a clean, well secured 91 element aerial
> pointed right at it. As with you, my TV reports great signal - 10/10
> strength and quality on all muxes (after some fiddling).
>
> Myth scans all channels properly, picture is generally good save for
> otherwise unexplained pixellation and drop outs every 20-30 minutes,
> similar to what you're describing. It seems to be occurring a little
> less frequently after some checking and redoing of connections, which
> suggests a signal problem to the card/PC (which is not shared by the
> TV).
>
> Trouble is - I'm not aware of any other readily available alternative
> cards in NZ which have dual terrestrial tuners. And even then, they
> could suffer similar problems or it isn't the card's fault, but
> elsewhere in the chain!
>
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>
>
There seem to be a few people with "reception" issues at the moment.
Just chipping in here to remind people that too much signal can overload
a tuner causing reception issues.  In particular a 91 element aerial
pointed at a "local" transmitter sounds like it could be overkill?

Me ... I am driving a HVR-1300 in my test system with a folded dipole
made from 300 ohm TV ribbon cable pinned to an indoor wall in a
downstairs room.  I am about 15km from kaukau and have line of sight.

Tony




Just reporting back on my reception issues with an HVR2200. I followed
Tony's suggestion and constructed a folded dipole with some leftover RG6
cable, an aerial balun, and a small cardboard box.

I followed the instructions and pictures here:

http://www.instructables.com/id/UHF-Folded-Dipole-Bowtie-Antenna/

My folded dipole is now sitting behind my TV - out of sight from She Who
Must Be Obeyed - facing directly at Fitzherbert.

I am feeding the HVR 2200 directly from this aerial.

Signal Quality seems good across all channels, and apart from issues with
pixellation approximately every 20 minutes, this works perfectly.

As I said earlier my folded dipole is pointed at Fitzherbert, and I have
the dipole sitting on its end, as the signal from Fitzherbert is polarized
vertically.

I believe the Pixellation problem every 20 minutes may have been due to missing
firmware. Specifically, my system was not loading the firmware for the tda10048
devices. It was successfully loading the saa7164, and tda18271 firmware, however
the tda10048 firmware file was missing.

I downloaded HVR-12x0-14x0-17x0_1_25_25271_WHQL.zip, and extract.sh from:

http://www.steventoth.net/linux/hvr22xx/

Then extracted the file dvb-fe-tda10048-1.0.fw using extract.sh, and copied the
firnmware file to lib/firmware.

Since then I have made four recordings with no pixellation issues whatsoever.
  
The Linuxtv.org wiki describes the tda10048 as a DVB-T demodulator.

I am not completely convinced that the pixellation issue was caused by this
missing firmware file. However results so far are encouraging.

What I don't understand is if this was the cause of the pixellation issue,
how then did the card manage to work while an apparently important component
- the tda10048 - was not actually functioning?

Cheers,
John.