Discussion
Today I got a Sony Freeview box for my ageing mother, who's virtually chair-bound and so TV is her only form of entertainment.
I was expecting possible problems with signal strength but there's one puzzle I can't figure. Most of the stations are 100% OK with a few, eg Channel 5, very broken up. However I was surprised to see that not only were 3 (ITV) and 4 (Channel 4) completely missing. I did the auto-tune procedure twice and it found 65 channels, but absolutely *nothing* for 3 and 4... not a peep.
My questions are: (1) What's the simplest/cheapest way of boosting the signal to get C5 etc, and (2) can anybody tell me why 3 and 4 are completely missing?
Cheers all
I was expecting possible problems with signal strength but there's one puzzle I can't figure. Most of the stations are 100% OK with a few, eg Channel 5, very broken up. However I was surprised to see that not only were 3 (ITV) and 4 (Channel 4) completely missing. I did the auto-tune procedure twice and it found 65 channels, but absolutely *nothing* for 3 and 4... not a peep.
My questions are: (1) What's the simplest/cheapest way of boosting the signal to get C5 etc, and (2) can anybody tell me why 3 and 4 are completely missing?
Cheers all
The channels are fed in different groups, called multiplexes (or "muxes" for short).
It's a binary thing - you can either receive a mux or you can't, depending on your signal strength. Different muxes reside on different frequencies and are allocated differing bandwidths (terrain, weather and distance from the transmitter all contribute to determine what you can or can't receive), so just because you receive one doesn't mean you'll receice another.
Check out this link. ITC and C4 appear to reside on Mux 2, and if you're not getting those channels then you won't get anything else on Mux 2.
The solution is to get a signal booster or a better aerial, of course assuming that there is a decent signal to receive in the first place.
For signal boosters, you can either get a masthead amplifier (one you stick right next to the aerial) or an in-line one that is actively mains powered and just boosts the signal along a string of coax cable that runs to your TV.
Remember that signal boosters boost do not reduce the signal to noise ratio - they boost just as much rubbish as they do actual signal, but it may just pump up your signal beyond the digital reception thresholds so that the error correction can do the rest.
In my case signal boosters make it worse!
You can get them from Argos or B&Q.
It's a binary thing - you can either receive a mux or you can't, depending on your signal strength. Different muxes reside on different frequencies and are allocated differing bandwidths (terrain, weather and distance from the transmitter all contribute to determine what you can or can't receive), so just because you receive one doesn't mean you'll receice another.
Check out this link. ITC and C4 appear to reside on Mux 2, and if you're not getting those channels then you won't get anything else on Mux 2.
The solution is to get a signal booster or a better aerial, of course assuming that there is a decent signal to receive in the first place.
For signal boosters, you can either get a masthead amplifier (one you stick right next to the aerial) or an in-line one that is actively mains powered and just boosts the signal along a string of coax cable that runs to your TV.
Remember that signal boosters boost do not reduce the signal to noise ratio - they boost just as much rubbish as they do actual signal, but it may just pump up your signal beyond the digital reception thresholds so that the error correction can do the rest.
In my case signal boosters make it worse!
You can get them from Argos or B&Q.
-DeaDLocK- said:
The channels are fed in different groups, called multiplexes (or "muxes" for short).
Excellent work sir
It seems to be Multiplex 2 that's missing. I got a signal booster today and that's fixed the problem on the weak channels, but there's still no sign at all of ITV or Ch4. Looks like the only answer is a better aerial, but that'll be £100 I guess so she'll probably stay with analogue for 3 and 4. 
£100, we got one with all the cable and installed it ourself for < £40 (the cable was £10). When I got freeview for my TV we picked up another aerial at £11 and it works better than the expensive one for the main TV.
All I need to do is figure out how to stop it popping and banging cheaply and I'm set. I know it's frequency and spikes on teh main ring, but I'm blowed if I'm paying £14.99 at Maplins for a 4-way to solve it.
>> Edited by docevi1 on Tuesday 29th March 18:30
docevi1 said:
Whilst I'm a DIY man I don't have the necessary ladders to work on the roof, so that £100 included labour.
docevi1 said:
When I got freeview for my TV we picked up another aerial at £11 and it works better than the expensive one for the main TV.
Is that a set-top one? I saw one in B&Q but it was ugly and small and I didn't think it would do much.
>> Edited by simpo two on Tuesday 29th March 18:39
simpo two said:No, mine goes through the ceiling and into our loft (as does the one for the main tv). It gets a damned good signal considering out location on a valley side mind.
When I got freeview for my TV we picked up another aerial at £11 and it works better than the expensive one for the main TV.
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