Digital TV Reception

Hi there,
Has anyone got problems with there Dual Screen TV?
I am talking about the passengers ability to watch TV whilst on the move. My 62 plate Dynamic is unwatchable.. It continually Freezes and pixilates, LR dealer can't find anything wrong.. It's ok when stationary, only has a problem when moving..everything else works 100%.
Regards. Steve

The way UK Digital TV 'works' means that reception on the move will be pretty much useless.

Just consider the difficulties some people have in receiving stable TV on a home TV with a directional roof-mounted 18 element yagi pointed directly at the transmitter; now consider the situation in the evoque, with a pair of poor gain panel antennae mounted in the rear side screens, at barely shoulder height, being whizzed along amongst buildings or hedges/trees ... don't stand much chance.

On one of my work journeys I travel past (in good line of sight) the Mendip transmitter. Whilst i can get some reception, it is far from watchable, and as soon as I get a bit further away from it and amongst buildings and stuff, it is more off than on. However it usually works fine once I'm parked up.

The reason for this issue isn't necessarily signal strength, but quality of the signal and the fact that it's a digital data stream. There is only so much data that can be squeezed into each 'channel' and part of that will be error correction data, but simplistically, because in the UK they have tried to squeeze as many channels in as possible, and to try and enable the maximum number of people to receive it without ramping the power up, they have less 'error correction'. As a rule that's fine when your TV and aerial is stationary as there is no variable multi path distortion of the signal (seen as ghosting on the old analogue signal) but when moving, the signal strength and quality will be varying so much, there just won't be enough good data to be able to correct the errors. Some channels (such as the BBC/ITV) may be better than the commercial channels as there are less logical channels squeezed into each old UHF frequency.

DTT was never designed as a mobile service, and it annoys the hell out of me when the sales people try and tell you it is....

Thanks Trapdoor.
I have spoken to two dealers today that tell me it works fine in other Range Rovers / Evoques.
I see your theory, but why would they market and sell (as an optimal extra on some models) a TV that doesn't really work whist moving??

Sales gimmick. Never worked well in my X3 either, although before DSO when the analogue was still active on the 5 channels, it was passable to watch on the move. After DSO, a waste of time.

There are going to be some areas where it will work reasonably well, but the coverage of DTT in the UK is not that great, which is why many people need high-gain wideband roof-mounted aerials, whereas before DSO, most channels were well grouped into the standard aerial groupings A, B, C/D, E & K and depending whether you are on a main station or relay transmitter will dictate polarisation (H for main, V for relay). The car antennae is a flat omni-directional pair in diversity mode which helps, but it also has to cater for both H & V polarisation and a significantly reduced ERP (effective radiated power) at the transmitter end.

Finally, the transmitters don't send a signal of the same strength out in all directions. Have a look here:

http://www.ukfree.tv/txdetail.php?a=ST547775

This shows the 'radar chart' for Bristol Kings Weston relay. As you can see, parts of the radiation pattern to the North are severely 'restricted' and are some 10db down on Southerly aspects. each -3db HALVES the available 'signal power'. And then look at the transmitter power for each multiplex. 200W at best. Our local relay is 16W!!

There are just so many variables that for JLR to claim good TV reception on the move is pretty silly.

Thanks again Trapdoor

(20-02-2014 09:53pm)Steve.mckenna2 Wrote:  Thanks again Trapdoor

Yes, good comment from Trapdoor. It's interesting that on the RRS configurator at least, they don't guarantee this £800 option will work. Personally, I think it's a waste of time and I do not like to see it bundled in with non-optional option packs like the Lux pack. You cannot now buy the Si4 engine without the Lux pack and doesn't that include the TV tuner?

In what country? The new configurator lets you do a dynamic Si4 without lux pack and I have one on order and being delivered in march.

(21-02-2014 08:51am)MarkA_ Wrote:  In what country? The new configurator lets you do a dynamic Si4 without lux pack and I have one on order and being delivered in march.

Interesting, for some bizarre reason, that is true of the 5 door but not, apparently, the 3 door which what I have. Whether that is really true or just some web-site SNAFU, I have no idea.

I'd wager a snafu