All posts by TK
Below are all of TK's postings, with the most recent are at the bottom of the page.
T
Two new Freeview channels - almost everywhere | Freeview newsSaturday 4 January 2020 10:48PM
Colchester
I think as old non-internet connected TV/receivers die off it would be useful to have ALL +1 channels removed from OTA DVB-T/T2 and placed as a red button option on each channel supporting it to stream the +1 channel content and free up OTA Freeview multiplexes for unique channels with the original OTA channel still being available for delayed viewing using PVR facility that is quite common via dedicated devices or external USB storage. Similar to how 4Music provides other streaming channels via the MHEG controlled buttons or some programs offer a HD internet stream of their normally SD content. (I wish more broadcasters would do that while freeview HD is such a patchwork for coverage of the full 15 HD channel service)
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T
Two new Freeview channels - almost everywhere | Freeview newsSaturday 4 January 2020 10:56PM
Colchester
L Wilkins: are any of your sky package you want on NOW TV platform? There could be a cheaper option to stream using a NOW TV subscription alongside FreeviewHD+ Play
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T
Why did the BBC just use 1.1 Million TV Licences to buy UKTV frSaturday 4 January 2020 11:15PM
Colchester
Robert: In my life people that have achieved something or have a desired attribute do not have to resort to say they have that attribute, it should be self evident.... like the person that says "I am extremely intelligent" or "I am a very interesting person" or "I am very funny" or in your case "I'm the height of witty ness", Isn't that supposed to be "wittiness"? the individual feels it needs to be said because it is NOT self-apparent means you may think it but no one else in this discussion or social interaction noticed it, thinks it or believes your proclamation of it! Jealousy of those that earn more or have more is unbecoming.
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T
High pressure causing channel loss through "Inversion" | FreeviSaturday 4 January 2020 11:42PM
Colchester
What would be really useful is to know the signal path and transgressing distant Freeview region signal so we could feasibly alter our aerial array to null out as much of the interfering signal as possible in the hopes of still receiving a signal with *enough* integrity from the local transmitter... I find it astounding that an entire set of local multiplexes can be obliterated by a single distant regions set of multiplexes! Did Freeview not consider the folly of placing multiplexes on the same UHF Channels/Frequencies across regions that have been known to suffer co-channel interference. They could have ensured at least ONE multiplex remains unmolested by the out of region transmitter! In my experience Areal erectors spend all their time maximising signal strength from the local transmitter and that's it... no consideration is given to the fact that DVB-T/T2 does not provide any picture improvement or stability once the signal reaches a certain signal level and quality threshold. The aerial orientation should be optimised to reject temperature inversion based long distance propagation while still providing a reliable local signal to reduce the impact of out of region co-channel interference.
It *should* be well known by industry experts what regions will interfere in any given atmospheric conditions and therefore there should be a database or map compiled for what regions are likely to interfere with any other given region based upon many decades of research going back through last century... after all the same propagation occurs to both analogue and DVB-T/T2 signals at any specific frequency.
This chuck it up and point it at the transmitter mast and get the strongest signal possible is not good enough to deal with sporadic overwhelming temperature inversion based propagation and Freeviews poor regional multiplex allocations.
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T
High pressure causing channel loss through "Inversion" | FreeviMonday 6 January 2020 3:58AM
Colchester
Chris.SE: Well yes and no... If it's coming from the rear or the array then one just needs to find a null point in the polar pattern and null out the rear signal and get it away from one of the spurious rear lobes. If there is polarisation twist then one should be able to null out the interfering co-channel off horizontal but not vertical signal by setting the array to perpendicular to the co-channel off horizontal but not vertically polarised signal and because there is significant acceptance off perpendicular the original horizontally polarised signal will be favoured over the null twisted originally horizontally polarised signal. In addition IF the interfering co-channel signal is arriving at receiving array at a different vertical incident angle then one should be able to aim the array away from that angle and past the desired signals optimum point so the co-channel signal may be at say the -12dB to -20dB point or greater in the array and the desired local transmitter signal may be -1dB to -3dB still a plenty strong enough local signal but significantly reducing the acceptance of the interfering co-channel signal. Of course IF the atmospheric propagation manages to arrive on exactly the same polarisation and incident angle AND bearing as the locally transmitted signal then I agree it should be a non-starter but from what I have learned over the past few decades I believe it's very rarely ever that since there is always some polarity skew through tropospheric ducting as I learnt it... Of course not all education of the past has turned out to be true in reality but I have no indication that the fact is incorrect.
Not all the transmitters can possibly interfere via tropospheric ducting since not all are in line with the a decent gain lobe on the array and so will be rejected, ALL the Freeview lite and other dead spot transmitters are V polarisation and tiny ERP so could not interfere... Not to forget that transmitters on different even adjacent channels will not interfere like they did on PAL analogue standard. What I found strange last night and to some extent tonight is the Sudbury multiplex broadcast on UHF channel 37 was and still is experiencing co-channel interference and did fall to no signal for several hours it's now at around 7% quality when it is normally at 100% quality... one of the other multiplex is very slightly down on quality 85% but not noticeable when watching the rest are apparently untouched in the high 80% signal strength and 100% quality yet not a single out of region multiplex is detected on any of the channels that are not in use by the local Sudbury transmitter... I guess that is suggesting an out of UK signal on UHF ch37 that is not in a compatible modulation scheme to UK DVB-T/T2 is the cause! It is a non-analogue TV signal as nothing is detected at that frequency using ATV manual scan... I find it difficult to believe nothing can be done to mitigate any of these tropospheric ducting problems. Much of it is understood quite well, but digital receivers make it difficult to fine tune aerial array alignment to favour one signal over another on the same bandwidth... Just for a test using the 602MHz compromised Sudbury multiplex ... not being able to use my normal large log periodic array as it's communally shared by other flats in the building I dug out an old set top 3 director one reflector aerial and determined the interfering signal is coming from Europe using an incompatible modulation so our DVB-T2 receivers will not demodulate and decode it... and the polarisation was originally Horizontal and had been skewed such that by adjusting my aerial OFF horizontal to the 10 past 8 angle as opposed to 15 past 9 standard my receiver was able suppress some of the back end Euro signal enough for the local NNW Sudbury signal to be resolved and scanned. OK this is not a conclusive test but it does suggest to me that it is possible on an individual basis to optimise aerial array placement to reject certain sources of interference by adjustment in real-time. It is unlikely that a single position would be found that would cater to all sources of tropospheric propagated signals but the ability to rotate in 3 axis an array could mitigate many incidences of such co-channel interference enough to let the encoded FEC to produce a watchable view-able DVB-T2 signal.
Also found that I am currently receiving PSB1 and PSB2 from Dover (Kent) on this old indoor aerial just clean enough to search and find the channels on them manually with a polarity skew of a few degrees off horizontal, no doubt if I had a 20+ element log-periodic outside on a rotating mount I could probably watch it and get the other lower power MUX's at the moment too but those are not the interfering out of area transmissions as they are all on non-conflicting channels with Sudbury MUX's Just got a 84% signal strength on Sudbury CH37 MUX using the indoor tiny aerial and 100% quality compared to 50% signal strength and 82% quality on loft 24 element log periodic originally aligned for optimum clear of atmospheric interference as advised by Arial erector experts. To me that is proof of concept... both aerials are using same branded same gain and noise specs distribution amplifiers just for fairness. 100% quality and practical rejection of the rear EU signal was achieved when pointing the aerial downward around 10 degrees off horizontal but facing towards Sudbury this allowed near perfect reception of the MUX that was not at no signal but was less than optimal quality and signal strength due to co-channel interference from a rear'ish out of region tropospheric tunnelled signal.
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Saturday 4 January 2020 10:10PM
Colchester
Why can't local regions switch in their regional SD or HD content in up-scaled if necessary trans-coded on the fly to replace the national HD regional content OR the national Regional content temporarily altered to a fixed bit rate for its duration of a slightly lower bit rate that will work with all other content on the HD multiplex so regional providers can encode their regional content to that spec for switching in when regional news items and other regional shows are broadcast rather than forcing viewers to either watch Meridian regional content or a stupid animated graphic for the duration of the regional slot... Most people would prefer up-scaled SD being inserted in the HD regional slots than having to either switch channel to a full SD local feed or suffer a completely pointless animation and sound track on BBC streams or an out of region program in commercial HD channels. Also Why does Freeview ALLOW BBC to waste CBBC & CBBC HD night time bandwidth when it is transmitting no content just a pointless animation and repeating filler audio stream? That bandwidth could be allocated to another HD channel or 3 to 5 SD channels or even some community run streams....