|
|
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 |
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 |
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 |
Strange Happenings on Retuning a Digi Box
On Fri, 10 Jan 2014 22:04:15 -0000, 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 Some or all of: Upgrade to the latest firmware if you haven't already. Delete all your existing channels and do a manual tune for CP. Buy a variable attentuator and put it in the aerial feed while auto-tuning to get rid of the unwanted weak transmissions. Do not leave channels above 800 on a T2 as it can cause problems with Accurate Record. |
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 |
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 |
Strange Happenings on Retuning a Digi Box
"Ian Jackson" wrote in message ... 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. |
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. |
Strange Happenings on Retuning a Digi Box
In message , r brooks
writes "Ian Jackson" wrote in message ... 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 |
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 |
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 |
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 |
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 |
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 |
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 |
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. |
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 |
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 |
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 |
Strange Happenings on Retuning a Digi Box
In message , Bill Wright
writes 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. If you leave it in, and there's only a few dB between the wanted and the unwanted, if the wanted drop a little, they may become marginal, and you'll find that some channels drop out at times. People forget to use it when they do a retune OK, so maybe leave it connected in circuit as a reminder, but turn it to minimum attenuation. , and it could help with 4G (etc) problems. Maybe (when it's a case of severe overload). On the other hand, the relative levels of the TV and 4G signals won't change as you twiddle the attenuator. I suppose it depends on the mechanism of the interference. -- Ian |
Strange Happenings on Retuning a Digi Box
Ian Jackson wrote:
I usually leave it in as long as long as the wanted channels are plenty strong enough. If you leave it in, and there's only a few dB between the wanted and the unwanted, if the wanted drop a little, they may become marginal, and you'll find that some channels drop out at times. Yes agreed, but see below. Maybe (when it's a case of severe overload). On the other hand, the relative levels of the TV and 4G signals won't change as you twiddle the attenuator. I suppose it depends on the mechanism of the interference. I was really thinking, I suppose, about the situation where the attenuator is on the input to the distribution amplifier. In that case it could very likely reduce 4G problems. That would be the best place for it as long as there is a largish ratio between the wanted and unwanted TV signals. That is the most common situation after all. Given the extreme sensitivity of many modern receivers it is quite common to have channels appear in the 800s that are from muxes 40dB or more below the wanted signals. Bearing in mind the directional properties of the aerial, if the said aerial is properly installed and is not a turd on a stick there should almost always be a large ratio between the wanted and unwanted signals. Consider the case where the wanted and unwanted signals are of the same field strength. The directional properties of the aerial should be able to provide a decent ratio between them. The exception would be when they come from the same direction and have the same polarisation. Another exception is when reception is from a distant transmitter (most likely a main station) but there is a local relay close by. The relay cannot be used because it is Freeview Lite or because signals are hoplessly garbled by reflections. This happens in some of the urban areas near the Crosspool mast, where trees and topography conspire to deliver to some locations massively strong muxes that are mangled to death. Even if they are decodable they are unreliable. Aerials look towards Belmont, so passive filters are no help. At one recent job at a sheltered scheme we found the aerial producing signals from Crosspool that were dancing up and down and all over the place, but were around 10dB stronger than the (wanted) Belmont signals. This was only 2km from Crosspool but screened by trees on a high bank. The aerial was one of the popular huge wideband high gain things (it was a Superbo Antennisimo Fantastico Gereralisimo Grandioso with 164 elements and a built-in microvolt maximiser, as I remember). We installed two log periodics phased together, and achieved far better results. This sort of thing: http://www.wrightsaerials.tv/ourwork/018.shtml but the spacing was arbitrary because the ****e (Crosspool) was coming at us from all directions. Bill |
Strange Happenings on Retuning a Digi Box
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. If you leave it in, and there's only a few dB between the wanted and the unwanted, if the wanted drop a little, they may become marginal, and you'll find that some channels drop out at times. People forget to use it when they do a retune OK, so maybe leave it connected in circuit as a reminder, but turn it to minimum attenuation. , and it could help with 4G (etc) problems. Maybe (when it's a case of severe overload). On the other hand, the relative levels of the TV and 4G signals won't change as you twiddle the attenuator. I suppose it depends on the mechanism of the interference. Though sometimes if the level of the interferer can be taken down enough so that it doesn't drive the RX frond end into distress then that can be useful to permit reception of the weaker signal.. Bill W might know isn't there a new box out that you can prog your postcode into and it only tunes the allocated TX for that area?.. -- Tony Sayer |
Strange Happenings on Retuning a Digi Box
In message , tony sayer
writes 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. If you leave it in, and there's only a few dB between the wanted and the unwanted, if the wanted drop a little, they may become marginal, and you'll find that some channels drop out at times. People forget to use it when they do a retune OK, so maybe leave it connected in circuit as a reminder, but turn it to minimum attenuation. , and it could help with 4G (etc) problems. Maybe (when it's a case of severe overload). On the other hand, the relative levels of the TV and 4G signals won't change as you twiddle the attenuator. I suppose it depends on the mechanism of the interference. Though sometimes if the level of the interferer can be taken down enough so that it doesn't drive the RX frond end into distress then that can be useful to permit reception of the weaker signal.. Where something is being driven into nonlinearity by a strong signal, it's nonlinear for all signals, and the addition of a front-end attenuator is a well-established possible cure for a multitude of problems. Bill W might know isn't there a new box out that you can prog your postcode into and it only tunes the allocated TX for that area?.. That could lead to problems when the signal from your assigned TX is poor where you live, and you have to receive another. You would have to fiddle things by using a false postcode - one for the area definitely covered by TX you actually wanted to tune to (like you can do with Freesat if you want a specific ITV area local content). Maybe every TX should have had a 'tune to me' code for you to enter. On the other hand, it's probably a darn sight easier for every TV receiver and STB to be obliged to have manual tuning. -- Ian |
Strange Happenings on Retuning a Digi Box
tony sayer wrote:
Bill W might know isn't there a new box out that you can prog your postcode into and it only tunes the allocated TX for that area?.. Most of them now ask for your country and region. Unfortunately they often then go on to ignore the information. I don't know whether this is the fault of the receivers or the givers. Bill |
Strange Happenings on Retuning a Digi Box
On 19/01/14 13:36, Ian Jackson wrote:
In message , tony sayer writes 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. If you leave it in, and there's only a few dB between the wanted and the unwanted, if the wanted drop a little, they may become marginal, and you'll find that some channels drop out at times. People forget to use it when they do a retune OK, so maybe leave it connected in circuit as a reminder, but turn it to minimum attenuation. , and it could help with 4G (etc) problems. Maybe (when it's a case of severe overload). On the other hand, the relative levels of the TV and 4G signals won't change as you twiddle the attenuator. I suppose it depends on the mechanism of the interference. Though sometimes if the level of the interferer can be taken down enough so that it doesn't drive the RX frond end into distress then that can be useful to permit reception of the weaker signal.. Where something is being driven into nonlinearity by a strong signal, it's nonlinear for all signals, and the addition of a front-end attenuator is a well-established possible cure for a multitude of problems. Bill W might know isn't there a new box out that you can prog your postcode into and it only tunes the allocated TX for that area?.. That could lead to problems when the signal from your assigned TX is poor where you live, and you have to receive another. You would have to fiddle things by using a false postcode - one for the area definitely covered by TX you actually wanted to tune to (like you can do with Freesat if you want a specific ITV area local content). Maybe every TX should have had a 'tune to me' code for you to enter. On the other hand, it's probably a darn sight easier for every TV receiver and STB to be obliged to have manual tuning. In case of strong wanted and unwanted the trick is to align the antenna - a good directional one, - so the unwanted coincides with one of the nulls in the lobe pattern. Getting the main signal 'on beam' is far less important than getting the unwanted signal 'off beam' with luck you can also attenuate the main beam enough not to need reduction either. using a laptop with a tuner dongle in it up in the loft or even on the roof is a way to do all this. Though you would have to be very close to a transmitter to get into front end overloading. I've had no problems a couple of miles from e.g sandy heath.. -- Ineptocracy (in-ep-toc’-ra-cy) – a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers. |
| All times are GMT +1. The time now is 05:45 PM. |
Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
HomeCinemaBanter.com