No DVB-T2 signal fine

[Bill]

Hi,
Anyone know why my 6220 only shows DVB-T channels? This is in MediaPortal, as the card is not recognised at all in TBS software.
I can get very weak HD which is barely watchable. I tried a Humax box with the same aerial, and it reported a strong DVB-T2 signal with 100% quality.

[CyberSimian]

I can get very weak HD which is barely watchable. I tried a Humax box with the same aerial, and it reported a strong DVB-T2 signal with 100% quality.

I have got a TBS 6284 card which I use with Windows Media Center. But I also have a Humax HDR-Fox-T2 DVR. I have noticed that the tuners in the Humax seem to be much better at coping with weak signals than the tuners on the TBS 6284 card. (I think that the 6220 uses the same tuner module as the 6284.)

At my location, there is one MUX (a DVB-T MUX) that is unwatchable when the weather is unfavourable; every few seconds the picture blanks, and then re-appears in pixelated form before reforming fully. In contrast, under the same conditions the Humax picture has barely any interruptions. The TBS and Humax tuners are fed from the same aerial, but pass through different amplifications, such that the Humax tuners receive a less-amplified (i.e. weaker) signal than the TBS tuners; but the Humax still gives the better result!

I don't know whether the Humax tuners are more sensitive, or whether they simply perform better error correction than the TBS tuners.

The problem that you have with your DVB-T2 MUX may be because it is weaker than the other MUXes. Have you tried using an aerial amplifier?

-- from CyberSimian in the UK

[Bill]

We live just outside the shadow from a line of hills which just clips our signal from the Sutton Coldfield transmitter. So I've put up a whopping XB16B aerial on a 4m pole (from ATV Aerials). I have an 8-way distribution amp in the loft, and this goes direct to the 6220. The HUMAX box reports a DVB-T2 signal with 98% quality, and has no problem with HD channels, so I don't think I have a weak signal. I've even tried fiddling with a variable attenuator in case the signal is too strong.

Looking at the details for the Sutton Coldfield transmitter, the HD channels are only broadcast on the PSB3 MUX, using 256QAM which is DVB-T2. (http://www.ukfree.tv/txdetail.php?a=SK113003)
The 6220 has never given any indication of picking up DVB-T2, but does show weak HD channels, similar to the symptoms you describe, so it must be receiving DVB-T2.

I think its just that TBS's tuner is pants compared to Humax's.

There's not much choice out there yet. Does anyone have better experience with BG or Hauppage nanostick?

[CyberSimian]

The HUMAX box reports a DVB-T2 signal with 98% quality, and has no problem with HD channels, so I don't think I have a weak signal.

Do you mean 98% quality, or 98% strength?

98% quality indicates that the Humax is receiving an imperfect signal, which might be too imperfect the the TBS tuners to handle. On the other hand, 98% strength would be a very strong signal and might result in overload. (I note that you tried a variable attenuator, presumably with no improvement.)

For comparison, my Humax gives perfect DVB-T2 reception with 100% quality and 73% strength.

-- from CyberSimian in the UK

[Bill]

The Humax was reporting 98% Quality. Could't see a strength figure, and didn't have much time to look.

I've also had a look through our BT Vision box down in the lounge. We're getting 90dBuV strength and 100% quality and 19dB carrier to noise ratio on all non-HD channels.

The 6220 via MediaPortal shows 50% strength and 52% quality on BBC1HD. It also says its a DVB-T signal. The 1 to 22dB attenuator on the 6220 made no change in strength/quality readings from one extreme to the other, which is puzzling.

The word is that over 80dBuV will need an attenuator. There's good info here: http://www.aerialsandtv.com/ampsandsplitters.html

I'll try the attenuator between the aerial and the amp next, instead of on the TBS input.

[Bill]

Putting the attenuator before the amp did the trick. Twiddled the pot until the TBS quality max'd out. TBS signal quality now up to 62, strength 50. HD works fine now.

BT Vision box now reporting 62dBuV, 100% quality.
I guess the Humax box has a much more robust receiver than the TBS card.
Now I just need to find out why the TBS software can't see the card.

The ATV Aerials web site is an excellent source of info.

Thanks for your help CyberSimian.