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#1
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
Grateful for any advice on my situation with a Digi Box, when i've just done
a *factory-default* on a Humax HDR Fox T2, which I did because i was missing some TV channels. I'm located in Finchley North London near a Relay Station, but my main transmitter is Crystal Palace. When i did my factory default the BBC TV programs were rubbish (picture breaking up). I remembered some advice to use a 'splitter' to reduce the signal strength for some reason when doing the re-tune. After re-tuning using the splitter the BBC stations as well as all the other stations seem to work OK. But I now get some HD stations in the channels numbered in the 800s' as well as the 100s. The HD channels in the 100s work ok, but all the HD channels in the 800s are still breaking up. Grateful for any advice on what I might usefully do further. Thanks |
#2
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
r brooks wrote:
After re-tuning using the splitter the BBC stations as well as all the other stations seem to work OK. But I now get some HD stations in the channels numbered in the 800s' as well as the 100s. The HD channels in the 100s work ok, but all the HD channels in the 800s are still breaking up. If the channels in the 800s are duplicates of the ones in the 100s, ignore them. They won't eat anything. Bill |
#3
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
Well Crystal Palace does seem to lose channels when I do a retune. I've
found that doing a factory retune with no aerial, even though the box was reset first makes this better. I think though that your main issue is that you are getting two transmitters and the box is throwing them in as it finds them. If you are lucky they end up with the weaker ones up on the high channels but this does not always happen as I discovered here during a tropo lift last autumn. I guess an attenuator is not really what you want unless you know for sure that the signals from the relay are lower, which I'm guessing they are not even though they may be cross polarised. Does the box in question allow you to see the channels the multiplexes are on that you have in your main channels and if they are not the ones you want there, then you need some way to re order them. Trouble is after any retune things tend to get scrambled again. Brian -- From the Sofa of Brian Gaff Reply address is active "r brooks" wrote in message ... Grateful for any advice on my situation with a Digi Box, when i've just done a *factory-default* on a Humax HDR Fox T2, which I did because i was missing some TV channels. I'm located in Finchley North London near a Relay Station, but my main transmitter is Crystal Palace. When i did my factory default the BBC TV programs were rubbish (picture breaking up). I remembered some advice to use a 'splitter' to reduce the signal strength for some reason when doing the re-tune. After re-tuning using the splitter the BBC stations as well as all the other stations seem to work OK. But I now get some HD stations in the channels numbered in the 800s' as well as the 100s. The HD channels in the 100s work ok, but all the HD channels in the 800s are still breaking up. Grateful for any advice on what I might usefully do further. Thanks |
#4
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
On 10/01/2014 22:04, r brooks wrote:
[...] After re-tuning using the splitter the BBC stations as well as all the other stations seem to work OK. But I now get some HD stations in the channels numbered in the 800s' as well as the 100s. The HD channels in the 100s work ok, but all the HD channels in the 800s are still breaking up. Grateful for any advice on what I might usefully do further. Thanks Try a manual retune - page 53 in the user guide and http://www.digitaluk.co.uk/coveragec...anual_retuning -- Andy |
#5
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
In message , Andy Wade
writes On 10/01/2014 22:04, r brooks wrote: [...] After re-tuning using the splitter the BBC stations as well as all the other stations seem to work OK. But I now get some HD stations in the channels numbered in the 800s' as well as the 100s. The HD channels in the 100s work ok, but all the HD channels in the 800s are still breaking up. Grateful for any advice on what I might usefully do further. Thanks Try a manual retune - page 53 in the user guide and http://www.digitaluk.co.uk/coveragec...anual_retuning Unfortunately, not all set-top boxes give you the option of doing a manual tune (or maybe the facility is hidden somewhere in the menus). If you have to do an automatic tune, rather than use a splitter, a 20db variable attenuator will give you better control of the signal level. I was in B&Q yesterday, and I saw they do one (£7?) - which, if you need one quickly, might be more convenient than getting one elsewhere online. -- Ian |
#6
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
"Ian Jackson" wrote in message news In message , Andy Wade writes On 10/01/2014 22:04, r brooks wrote: [...] After re-tuning using the splitter the BBC stations as well as all the other stations seem to work OK. But I now get some HD stations in the channels numbered in the 800s' as well as the 100s. The HD channels in the 100s work ok, but all the HD channels in the 800s are still breaking up. Grateful for any advice on what I might usefully do further. Thanks Try a manual retune - page 53 in the user guide and http://www.digitaluk.co.uk/coveragec...anual_retuning Unfortunately, not all set-top boxes give you the option of doing a manual tune (or maybe the facility is hidden somewhere in the menus). If you have to do an automatic tune, rather than use a splitter, a 20db variable attenuator will give you better control of the signal level. I was in B&Q yesterday, and I saw they do one (£7?) - which, if you need one quickly, might be more convenient than getting one elsewhere online. -- Ian ---------------------------------------------------------------------------------------- Ian thanks. Two questions: What function does the use of a splitter serve, I understand it weakens the incoming signal but what is the purpose of that please? If I get a variable attenuator from b and q, what kind of adjustment would I want to be making with it? Thanks. |
#7
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
In message , r brooks
writes "Ian Jackson" wrote in message news In message , Andy Wade writes On 10/01/2014 22:04, r brooks wrote: [...] After re-tuning using the splitter the BBC stations as well as all the other stations seem to work OK. But I now get some HD stations in the channels numbered in the 800s' as well as the 100s. The HD channels in the 100s work ok, but all the HD channels in the 800s are still breaking up. Grateful for any advice on what I might usefully do further. Thanks Try a manual retune - page 53 in the user guide and http://www.digitaluk.co.uk/coveragec...anual_retuning Unfortunately, not all set-top boxes give you the option of doing a manual tune (or maybe the facility is hidden somewhere in the menus). If you have to do an automatic tune, rather than use a splitter, a 20db variable attenuator will give you better control of the signal level. I was in B&Q yesterday, and I saw they do one (£7?) - which, if you need one quickly, might be more convenient than getting one elsewhere online. -- Ian ------------------------------------------------------------------------ ---------------- Ian thanks. Two questions: What function does the use of a splitter serve, I understand it weakens the incoming signal but what is the purpose of that please? If I get a variable attenuator from b and q, what kind of adjustment would I want to be making with it? Thanks. I mistakenly thought I saw someone advised inserting a splitter in the aerial feed (to lower the signal level) - but looking back, it must have been in another thread! However, sometimes inserting a splitter in the aerial feed is suggested (as these are readily available). This will lower the TV signal level by 4 dB (6 for the cheap resistive ones) - and this might just may be sufficient to make the set-top box, when it's doing the automatic channel scan, ignore the unwanted, weaker signals and detect only the stronger wanted channels. Obviously, with a splitter (or any other fixed attenuator), you don't have much control over how much signal loss you put in (other than use more than one of them). The variable attenuator (as suggested by Paul), enables you to control how far you reduce the signal. A variable 20dB attenuator will enable you to reduce the signal by a maximum of 20dB (1/10th of the original), so with a bit of trial and error, you should be able to persuade the set-top box to 'see' only the strongest channels, and ignore the rest. Once you've done the scan, you should remove the attenuator, and only use it again if you need to do another scan. An obvious problem with the above is if the unwanted signals are stronger than the wanted ones. This might be the case if you want to receive the full complement of TV channels from the main transmitter, but a stronger local relay transmitter is offering a reduced number of channels (as many do). As you see, it's all a bit of a fiddle. It's a lot easier if your set-top box or TV set does allow you to do a manual tune. To do this, you'll need to enter (in turn) the individual transmission channel numbers. For Crystal Palace (standard definition) they are 22, 23, 25, 26, 28 and 29, with 33 and 37 for high definition (see link): http://www.ukfree.tv/txdetail.php?a=TQ339712&PGSTART=0 -- Ian |
#8
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
Ian Jackson wrote:
An obvious problem with the above is if the unwanted signals are stronger than the wanted ones. This might be the case if you want to receive the full complement of TV channels from the main transmitter, but a stronger local relay transmitter is offering a reduced number of channels (as many do). Much depends on the receiver. Does is simply chose by signal strength or does it chose by signal quality? Bill |
#9
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
r brooks wrote:
Ian thanks. Two questions: What function does the use of a splitter serve, I understand it weakens the incoming signal but what is the purpose of that please? The idea is to weaken the signals so that the weaker set (from the 'wrong' transmitter) are too weak to be stored. Meanwhile the stronger ones remain strong enough to be stored. If I get a variable attenuator from b and q, what kind of adjustment would I want to be making with it? Thanks. Trial and error until you achieve the above. Start at the max atten end. Bill |
#10
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
Ian Jackson wrote:
If you have to do an automatic tune, rather than use a splitter, a 20db variable attenuator will give you better control of the signal level. I was in B&Q yesterday, and I saw they do one (£7?) - which, if you need one quickly, might be more convenient than getting one elsewhere online. Or the free option, a loosely coupled pair of faraday loops (if that's the proper name for them). Bill |
#11
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
In article , Bill Wright
scribeth thus Ian Jackson wrote: If you have to do an automatic tune, rather than use a splitter, a 20db variable attenuator will give you better control of the signal level. I was in B&Q yesterday, and I saw they do one (£7?) - which, if you need one quickly, might be more convenient than getting one elsewhere online. Or the free option, a loosely coupled pair of faraday loops (if that's the proper name for them). Bill Well hats a nice idea.. And cheap too!.... -- Tony Sayer |
#12
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
tony sayer wrote:
Or the free option, a loosely coupled pair of faraday loops (if that's the proper name for them). Bill Well hats a nice idea.. And cheap too!.... When I was rigging for DER they wouldn't pay for attenuators, and the sets of the time needed one when in Ponty and Barnsley. So I made loops. My old German mentor showed me the trick, when I was a kid. Did I ever mention Hans? He was in the Hitler Youth as a lad, and then in 1945 him and his family lived in a sewer for months. He came to the UK on holiday in the late 40s and stayed. A good immigrant. Bill |
#13
Posted to uk.d-i-y
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Strange Happenings on Retuning a Digi Box
On Saturday, 11 January 2014 11:14:32 UTC, Ian Jackson wrote:
Try a manual retune - page 53 in the user guide and http://www.digitaluk.co.uk/coveragec...anual_retuning Unfortunately, not all set-top boxes give you the option of doing a manual tune (or maybe the facility is hidden somewhere in the menus). I suspect this one does given it's on page 53 of the user guide! ;-) |
#14
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
On 10/01/2014 22:04, r brooks wrote:
Grateful for any advice on my situation with a Digi Box, when i've just done a *factory-default* on a Humax HDR Fox T2, which I did because i was missing some TV channels. I'm located in Finchley North London near a Relay Station, but my main transmitter is Crystal Palace. When i did my factory default the BBC TV programs were rubbish (picture breaking up). I remembered some advice to use a 'splitter' to reduce the signal strength for some reason when doing the re-tune. After re-tuning using the splitter the BBC stations as well as all the other stations seem to work OK. But I now get some HD stations in the channels numbered in the 800s' as well as the 100s. The HD channels in the 100s work ok, but all the HD channels in the 800s are still breaking up. Grateful for any advice on what I might usefully do further. Thanks Your aerial is picking up signals from two different transmitters. When this happens Humax non YouView boxes replicate channels by placing them in the location you have cited. There is a solution but one way is to have your aerial realigned. |
#16
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Strange Happenings on Retuning a Digi Box
Gareth Davies wrote:
There is a solution but one way is to have your aerial realigned. Because of the extreme sensitivity of many modern DTT receivers this is unlikely to help, unless the aerial was grossly wrong in the first place. Bill |
#17
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Strange Happenings on Retuning a Digi Box
"Bill Wright" wrote in message ... Gareth Davies wrote: There is a solution but one way is to have your aerial realigned. Because of the extreme sensitivity of many modern DTT receivers this is unlikely to help, unless the aerial was grossly wrong in the first place. Bill ----------------------------------------------------------------------------------------- Conclusion: Bought a variable attenuator on line for £3.15 inc postage. screwed it out for maximum resistance (less one complete turn out of five turns) and it eliminated all channels in the 800 range on the factory default/automatic retune. Many thanks to all for helping me get good results. |
#18
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
In message , r brooks
writes "Bill Wright" wrote in message ... Gareth Davies wrote: There is a solution but one way is to have your aerial realigned. Because of the extreme sensitivity of many modern DTT receivers this is unlikely to help, unless the aerial was grossly wrong in the first place. Bill ------------------------------------------------------------------------ ----------------- Conclusion: Bought a variable attenuator on line for £3.15 inc postage. screwed it out for maximum resistance (less one complete turn out of five turns) and it eliminated all channels in the 800 range on the factory default/automatic retune. Many thanks to all for helping me get good results. Good conclusion. You can take it out until you do another scan. -- Ian |
#19
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
Ian Jackson wrote:
In message , r brooks writes "Bill Wright" wrote in message ... Gareth Davies wrote: There is a solution but one way is to have your aerial realigned. Because of the extreme sensitivity of many modern DTT receivers this is unlikely to help, unless the aerial was grossly wrong in the first place. Bill ------------------------------------------------------------------------ ----------------- Conclusion: Bought a variable attenuator on line for £3.15 inc postage. screwed it out for maximum resistance (less one complete turn out of five turns) and it eliminated all channels in the 800 range on the factory default/automatic retune. Many thanks to all for helping me get good results. Good conclusion. You can take it out until you do another scan. I usually leave it in as long as long as the wanted channels are plenty strong enough. People forget to use it when they do a retune, and it could help with 4G (etc) problems. Bill |
#20
Posted to uk.tech.digital-tv,uk.d-i-y
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Strange Happenings on Retuning a Digi Box
r brooks wrote:
"Bill Wright" wrote in message ... Gareth Davies wrote: There is a solution but one way is to have your aerial realigned. Because of the extreme sensitivity of many modern DTT receivers this is unlikely to help, unless the aerial was grossly wrong in the first place. Bill ----------------------------------------------------------------------------------------- Conclusion: Bought a variable attenuator on line for £3.15 inc postage. screwed it out for maximum resistance (less one complete turn out of five turns) and it eliminated all channels in the 800 range on the factory default/automatic retune. Many thanks to all for helping me get good results. For maximum reliability of the wanted signals try again with less attenuation, and again and again, until the unwanted signals reappear, then go back a step or two. Bill |
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