All posts by Mr K
Below are all of Mr K's postings, with the most recent are at the bottom of the page.
Just to update and say that these missing channels returned around 9pm shortly after I posted the above.
A BBC engineering page actually says that "COM7 CH55 reception variable you may not receive all these service..." when I put my address into it. Very odd. I'll see what happens today.
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Thanks for the info Chris, all is still good and levels have remained so since. A real mystery.
Out of curiosity I tried seeing how much attenuation the TV feed would stand before these missing channels became visibly pixelated/drop outs. I got to between 24 and 30db so very very odd that they all fell to zero on that day.
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I'm about 4 miles north of Blackpool and use a log rooftop aerial. My set up is the aerial feeding into the loft and into an (old now) Antiference four way distribution amp.
The feed to the main lounge is split 3 ways in the lounge (passive Triax splitter) and feeds a Sony 43" Android TV, a Panasonic HD recorder and an older Sony HDD recorder.
Moel Y Parc has always been an issue with the Sony as intermittent reception can confuse the timer settings for BBC in particular with it selecting the Moel Y Parc transmitter if the programme times happen to be different between that and Winter Hill.
That problem is 99% solved by adding a 15db attenuator to the Sony feed. The Triax splitter will already be adding around 6db to each of the three feeds.
The Sony TV reports CH55 @ 63% strength and 100% quality. CH54 is @ 99% strength and 100% quality.
The Sony with its massive attenuation reports all receivable channels at 100% quality. Signal strengths are:
CH21 @ 35%
CH32 @ 92%
CH37 @ 87%
CH40 @ 44%
CH49 @ 79%
CH50 @ 79%
CH58 @ 60%
CH59 @ 57%
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Chris.SE:
Well it used to be an Antiference RX20 but a few weeks ago it took a direct hit from what I assume was a seagull... it sounded like the roof was falling in. The old aerial was left pointing at Blackpool Tower rather than Winter Hill and so it all got replaced with a new Log type which I don't know the brand of unfortunately.
So all those signal levels are with the Log aerial.
Given that we will end up on Group A when its all over and done with even has me wondering whether a loft Yagi such as an XB10 might be viable.
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Chris.SE:
Postcode is FY5 2HS. There is enough space in the loft for something like an XB10 with there just being a central chimney running through the middle of the loft space. Should be enough space at the side though. I do realise it's one of those things you would have to try for real and that in the end it's an 'unknown' until you do.
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Chris.SE:
Thanks Chris. Out of curiosity I tried adding more attenuation to the feed to the Sony TV... so that is already a 3 way split and so around 6db down and I added a further 10, 12 and then 15db in turn.
Quality was 100% for the 10db, 99% for the 12db and 25% for the 15db. Digital cliff edge approaching rapidly I think. Signal strengths were 30, 25 and 13% respectively.
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Chris.SE:
Thanks for the link, those kind of things are really useful actually.
The big problem/s I have with juggling attenuators are these:
1/ The Sony HDD recorder (HXD870) has no means of preventing it background scanning for channels when in standby. Although any rogue entries can be deleted from the EPG and seeming got rid of that way I find that timer recordings still get confused and consequently the program from the wrong region will be recorded.
2/ The much newer (still current) Panasonic HD HDD recorder has a well documented issue of locking up and becoming unresponsive, usually overnight. Lots of customer reports of this. I've noticed it happens every time there is a change to the Freeview platform and so that leads to suspect it also locks up when out of region transmissions are strong enough to be logged as a new channel or a change in channel lineup. So I have an attenuator in that feed as well.
I'm hoping both these issues will be improved once the final shuffling is done.
The Sony TV just sorts everything automatically and never blinks.
Amplifying only to attenuate again breaks all the rules but it seems to provide a workable solution in my case. It would be interesting to see how much attenuation the incoming signal from the aerial could stand and perhaps use that as a basis for how well a loft aerial might perform... but you know what it's like... its a bit a chore going up there and running up and down ladders to look at the effect as you change something.
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Chris.SE:
That very problem you mention of HDMI leads and cable routing is something I came across a couple of years ago with this set up. I had wondered if I could dispense with the amplifier altogether and which is in the loft by the way and not external... and all seemed OK until the Sony recorder was turned on, and when it was BBC4 HD and News24 HD etc went AWOL. If I separated the leads somewhat then it was OK but having untidy wiring is something that drives me nuts and so the amplifier stayed. I hadn't got the Panasonic at that time.
I must admit I time shift pretty much everything and aside from the Sony's little tendency to want to grab out of band signals I have to say that it has been the single best bit of kit I have owned. On average I bet it has seen 4 to 5 hours daily use... it may even be more. The attenuators have pretty much 100% fixed those other issues though.
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Saturday 25 April 2020 7:31PM
I've lost COM7 today (never had issues before) on both a Sony Android TV and a Panasonic HDD recorder.
Fylde coast Cleveleys using large Antiference RX20 Yagi rooftop aerial.
It was fine at 12 noon today (25th April) as I recorded News24 in HD for 35 minutes. When watched live at 1:30pm all HD channels on this MUX had gone. The Sony has auto deleted them from the YouView lineup and the Panasonic just reports 'No Signal'. A signal check on the Panasonic show 0% for all these channels, all other MUXES and channels are good.
No hint of reception issues before this.