New HD channels pixellate on T2

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New HD channels pixellate on T2

(12 posts)

Maximax

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Please could anyone help with a pixel problem? We have line of sight about 12 miles to our transmitter (Divis, Belfast) and never had signal problems with Freeserve until the introduction of new HD channels. We have Com7HD on Channel 33 carrying Al-Jazeera, BBC4HD, BBC News24 and CBeebies.

These channels are perfect on the TV, but when Humax input is selected they are badly pixellated, they freeze for a second or so, and the sound breaks up every few seconds. I tried a manual tune of the Humax but no difference.

We had a high-gain aerial erected on the chimneyabout 5 yrs ago with incoming cable to Humax then to Sony TV. Signal detection figures are 42 on Ch33, and 44 to 49 on the other channels. Advice very welcome!

| Sat 18 Jan 2014 12:20:45 #1 |
grahamlthompson

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Hi welcome to the forum. Try plugging in a variable attenuator like this one and tweak for best quality.

http://www.ebay.co.uk/itm/TV-Aerial-Attenuator-Variable-0-20Db-Freeview-Digital-/150673681690?pt=UK_ConElec_TVAerials_RL&hash=item2314d9ed1a

| Sat 18 Jan 2014 12:31:34 #2 |
Martin Liddle

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Maximax - 10 minutes ago »
We had a high-gain aerial erected on the chimneyabout 5 yrs ago with incoming cable to Humax then to Sony TV. Signal detection figures are 42 on Ch33, and 44 to 49 on the other channels. Advice very welcome!

The Humax reports signal strength and signal quality; are the figures you have labelled signal detection the signal strength? What is the signal quality on the channels with problems?

| Sat 18 Jan 2014 12:33:28 #3 |
Maximax

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The signal strength on our problem Ch33 is 42, the figures for the remaining channels range between 44 and 49. The signal quality on all channels including problem ch33 is 100.

| Sat 18 Jan 2014 12:56:35 #4 |
Owen Smith

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I agree with the attenuator option. 12 miles away line of sight to a big transmitter like Divis should mean using a Log Periodic antenna to combat ghosting etc. while keeping gain down. The signal may be clipping in the HDR Fox T2's receiver and the reported value may be completely erroneous.

Why did you have a high gain antenna put up may I ask? Was there a different problem at the time pre DSO?

| Mon 20 Jan 2014 14:49:07 #5 |
Maximax

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The high gain aerial was recommended by the installer as TV signal has never been good in this area. We are on top of 150ft hill and Divis can be seen from our roof but rest of town is well below our level. The new channels are fine on the TV, just the Humax has the problem which is why I thought the signal was too weak, but I shall try an attenuator. Many thanks for your advice.

| Mon 20 Jan 2014 17:03:01 #6 |
Owen Smith

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Direct line of sight 12 miles from Divis and the installer said you had a weak signal? Very strange. More likely high gain antennas were all he had on the van, or he thought he could charge more for high gain.

Was there actually a problem with your reception before you had the high gain antenna installed? Ie. why was the installer called out in the first place?

An issue with the HDR Fox T2 has occured in the past, it seems to have more sensitive tuners (or did before a recent hardware change) than much other equipment. This is great in weak reception areas, but there have been cases before of everything else receiving find but the HDR Fox T2 needing an attenuator to avoid clipping. If the signal level goes up not down at some point as you attenuate then that's the problem.

| Mon 20 Jan 2014 17:37:43 #7 |
Maximax

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The installer was called out because our old aerial fell down after 15+ years and we needed a new one for HD anyway! The local TV shop recommended high-gain because both radio and TV signals had always been poor in the town which as I said is in a hollow. Anyway I shall obtain an attenuator and report back. Thanks again.

| Tue 21 Jan 2014 12:56:51 #8 |
Owen Smith

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The attenuator is at least cheap and easy to try, and will conclusively prove whether your signal is too strong or not.

| Tue 21 Jan 2014 13:34:02 #9 |
Maximax

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The attenuator arrived from Amazon this morning and we have perfect pictures on all channels. I didn't even turn the adjustment screw, just plugged it in and our problems were solved. Many thanks, folks, for your expert advice

| Sat 25 Jan 2014 16:28:02 #10 |