NTL MMDS\Digital signal question

por

Does anybody know if NTL can test the signal for a customer prior to subscribing for MMDS?
Apparently the house I rent always has had trouble getting MMDS (even though it is available from NTL in the area) and on the basis of that decided to go with Sky when I moved in. But now that NTL has a Digital MMDS service and I would like to give it a try, but test it before subscribing. Also will the new MMDS Digital increase the quality of the signal over the analogue version?

crawler

Por - digital has 2 states - working and not working analogue simply gets poorer and poorer until it becomes unwatchable.

If you PM me with your address I'll check it for you to see if you are in the coverage area.

Gwynston

por - where are you?

I'm getting NTL's MMDS Digital 10 miles north of Galway. It's been OK since installed in the summer, but it remains to be seen how it is during the winter months.

Last winter with MMDS analogue, picture quality was often terrible. With digital the picture is good, but if the signal is mediocre, the picture will just break up and/or freeze completely.

At least with analogue I could watch something in poor conditions. I'm afraid this winter I might simply lose pictures completely from time to time

crawler

Gwynston - Digital is far more resistent to interference than analogue - Analogue uses a carrier wave that is modulated and "noise" will greatly interfere with this. digital uses a combination of 2 states - "1"'s and "0"'s - and smarts for error correction etc....if Digital has been working well then it will probably continue to do so.

With any wireless link though you can get "outages" due to extreme weather - in particualr if lightening zaps your mesh!

Gwynston

Hi crawler,
Yes I understand the technology differences, but like you said yourself, digital either works or it doesn't. There's no dropoff like with analogue where at least if the signal is poor, you get something, even if it is not pretty.

By observing what happens when the MMDS digital system has problems, I've deduced that when signal quality gets down to a certain level (above which all that happens is some acceptable mild pixellation), the decoder struggles to keep up when having to do a lot of error correction.

Example: the image starting to skip frames with associated sound interference. As this goes on for a few seconds (as the signal continues to cause problems), more and more frames get dropped until eventually the picture freezes. Eventually after about 10 secs frozen, the decoder seems to abandon trying to catch up on it's processing and just jumps forward to the current signal and works OK again for a couple of minutes before this sequence repeats.

I've only seen this a couple of times, but I hope it doesn't get more frequent during the winter. Last night was stormy in Galway, and it was OK, so I'm keeping my fingers crossed.

crawler

Useful feedback - thanks.....