Just Sharing This 700Mhz clearance and potential interference to your TV

[jeallen01]

According to the Ofcom study, 600MHz does not actually mean 600MHz cutoff

The 600 MHz spectrum covers the range 550 to 606 MHz comprising seven 8 MHz
channels (channels 31 to 37) . The band was cleared of analogue TV on a region by
region basis during digital switch -over (DSO ). That process was completed in 2012

https://www.ofcom.org.uk/__data/assets/pdf_file/0026/42965/condoc.pdf

More info inside but it is a long read.

CH:

As you said, a very long read, and I only skimmed a little of that relating to the "600 MHz" band - looks to me like nothing is really a done deal as yet - but still means that the use of channels above Ch 30 may become progressively more vulnerable if used for local distribution in buildings.

Thinking that, assuming I stay with the existing Sky box with RF2 connector until it "dies", I might need to get that filter to put between the UHF antenna and the Loftbox. OTOH might have to try to "squeeze" the house distribution channel in between 2 of the existing DTT channels in the Ch 21-30 range = "fun" and some different filters with very sharp bandpass/rejection characteristics?

Might similar units be needed in communal distribution systems to protect the "whole" internal system?

Then again, what happens to that idea if the 2 (?) new DTT multiplexes (didn't get around to reading to see what they might be used for) in the 600MHz band do come on line ?

OTOH, looks like Ch 36 will stay free for the cross-border experiments - so maybe fit a Ch 36 "stopper" between the antenna and the Loftbox, and use that channel for the house system?

PS: If the existing Sky Box does dies (and it probably will at some time) then we get stuck with the new boxes with Wifi connection adapters - so even more congestion of the available Wifi channels? (Anyone know which of the 2.4 and 5GHz bands those adapters use? - I suspect the latter)

 

[davemurgtroyd]

PS: If the existing Sky Box does dies (and it probably will at some time) then we get stuck with the new boxes with Wifi connection adapters - so even more congestion of the available Wifi channels? (Anyone know which of the 2.4 and 5GHz bands those adapters use? - I suspect the latter)

The Sky HD WiFi boxes do NOT use WiFi for video distribution but merely for connection to the web. They have an IO port to which connects a "small black box" which provides an RF output in exactly the same way as earlier boxes. So basically they have swapped from an inbuilt RF modulator and external WiFi to an inbuilt WiFi and external RF modulator - so basically no change in mode of operation.

Sky Q boxes can use any of WiFi, ethernet or powerline to communicate with the mini boxes.

 

[jeallen01]

Dave
Thanks - my misunderstanding, and probably a misinterpretation of the description of the adapter.

So, do you know which channel(s) they use, as it seems that we could be back to the same issue of possible interference from the forthcoming changes in services above Ch 30?

 

[Channel Hopper]

Channel 36 might be kept as an open channel for this purpose since many video recorders and add-on modulators used this frequency by default.

 

[davemurgtroyd]

Dave
Thanks - my misunderstanding, and probably a misinterpretation of the description of the adapter.

So, do you know which channel(s) they use, as it seems that we could be back to the same issue of possible interference from the forthcoming changes in services above Ch 30?

Exactly the same range of channels and the firmware in the box gives exactly the same menus and options

 

[jeallen01]

Channel 36 might be kept as an open channel for this purpose since many video recorders and add-on modulators used this frequency by default.

CH: maybe that's why Section 4.14. of the Ofcom paper says this about Ch 36:
"
4.14 Any service that involves the use of a single channel will be subject to differing usage rights and experience markedly different levels of incoming interference in different parts of the UK. The exception is Channel 36, which, for historical reasons, is relatively unencumbered. Each channel carries its own unique set of rights and therefore some channels may be more or less suitable for a particular use than others. Further information on the current spectrum usage rights of the UK and its neighbours on channels 31 to 37 (including sources of incoming interference) is given in Annexes to this document."

So, looks like Ch 36 is the one to aim for - just as long we don't get any experimental "long distance" stuff" as discussed in 4.25 of the Ofcom paper (see the italicized bit) :
"
4.25 As mentioned above, the cleared 600 MHz band includes one channel – Channel 36 (590-598 MHz) – which is free from any issues of differing usage rights in different parts of the UK. Under our original 600 MHz award plans, we had considered it suitable for provision of a UK-wide single frequency network (SFN). However, for historical reasons connected to previous uses, Channel 36 is also clear across most of the rest of western Europe. This presents a valuable opportunity that is not often encountered in the UHF spectrum, for a European cross-border signal propagation study. Existing data is relatively old and incomplete and an understanding of signal propagation could aid future spectrum planning. The proposal is for a study to set up a temporary mesh network of about 15 transmitters and up to 40 receive sites covering the eastern part of Ireland, England, Wales, and areas of France, Belgium and the Netherlands bordering the English Channel and North Sea, i.e. in areas where channel 36 is presently unused. "

Exactly the same range of channels and the firmware in the box gives exactly the same menus and options

Dave:

Thanks - not having one of the newer boxes, I didn't know what options they have.

 

[scopus]

Going a bit off topic, but CH30 was little used throughout the country in analogue days, and when I bought my first NICAM VCR within a week their was a lift on and I received my first stereo signal from Crystal Palace up here in Staffordshire, long before Sutton Coldfield was converted. I think it was Jonathon Ross on with music from Natalie Merchant. Still have the recording somewhere....

 

[Channel Hopper]

Channel 30 was allocated to (Channel) 4 from Crystal Palace

 

[rolfw]

Just been to a seminar on 700mhz clearance, would appear that COM 7 and 8 multiplexes may disappear after 2020, for example, they will be temporarily moved to the mid 50s, sitting between where the up and downstream mobile frequencies will eventually be. Their future from there on is up in the air.

 

[jeallen01]

Just been to a seminar on 700mhz clearance, would appear that COM 7 and 8 multiplexes may disappear after 2020, for example, they will be temporarily moved to the mid 50s, sitting between where the up and downstream mobile frequencies will eventually be. Their future from there on is up in the air.

Rolf
What are the COM 7 and 7 multiplexes?

 

[Analoguesat]

Limited coverage low power muxes carried on some of the big transmitters.

 

[jeallen01]

Limited coverage low power muxes carried on some of the big transmitters.

A/S - many thanks - so probably not an issue for most of us in large urban areas if we use the major beams then?

 

[Analoguesat]

COM 7 seems to have the HD stuff on it and a whole load of minor interest stuff

As you are in London heres the Crystal Palace info:

https://ukfree.tv/transmitters/tv/Crystal_Palace

 

[jeallen01]

So both COM 7 & 8 changes ARE likely to affect DTV in London - not that we ourselves use DTV very much

 

[Analoguesat]

I gave up with DTT shortly after DSO. The signal was just awful here (~7 miles from Selkirk tx). In fact I took our tv aerial down & we went 100% satellite distribution. Never had any problems apart from the very occasional drop out when the monsoons have arrived or 6 inches of snow has built up on the arm of the dish

 

[PaulR]

Contrariwise, nearly all of our viewing is using Freeview in the UK.

COM 8 does not hold much of interest for us but COM 7 most certainly does. I would be sad to lose the HD versions of BBC4, C4+1 and 4seven, although the SD versions will still remain. The same can't be said about the wonderful Talking Pictures TV channel. An SD channel already (albeit transmitted using HD protocols) there is no other terrestrial alternative.

 

[jeallen01]

Paul

Given the continued development of technology I rather think that SD broadcasts will go the way of the old Band I/III 405 line analogue broadcasts when the 625 line UHF system came into operation - that could conceivably free channels for HD versions of the current SD channels.

 

[PaulR]

I would have absolutely no problem in the cessation of SD channels in favour of HD channels already being transmitted - although the BBC and, to a lesser extent, ITV would need to sort out their local content in HD.

HD versions of the films being shown on Talking Pictures TV would probably not add much TBH!

 

[william-1]

We still get Meridian ITV-1 HD in West Essex FreeView & Cable Why
So I watch Anglia East ITV-1 HD via Satellite as it covers my location,
Eventually Free-view will be just 2 Multiplexes per region by 2025 as the Mobile Broadband pockets are much deeper & will price Free-view out

 

[Topper]

HD versions of the films being shown on Talking Pictures TV would probably not add much TBH!

Upscaled sharper fringe patterning of B&W films showing men tweed jackets perhaps?