[Boostrail]

Hi

Can we please start a thread for discussion, feedback, and advice on the Sandy Heath DSO which is now only days away

A Major DSO starts on the 30th of March. My personal observations are:-

A transmitter which is rated as one of the highest power Analogue transmiters using the most efficient Group A wavelengths in Europe is about to be switched off.

Will the increased power digital transmissions cover the same service area as the od analogue service?

If you are already a Freeview user and live near to the transmiter will you have "over-signal" problems due to the very large increase in power?

Even if you already have satisfactory Freeview reception then you may find that the expansion to channels in the fifties will for many at a middle distance from the transmitter definitely mean you need a new aerial

[solidamber]

I'm on the outer edges of the signal from Sandy heath "near Newmarket" signal strength is low but get most channels with very occasional break up, just through an old bent aerial that was on the roof when we moved in, was told that the signal strength will increase after the switch over. we have sky and mutiroom, its only a small TV in the kitchen that has freeview so don't want to be installing a new aerial. What is meant by expansion to channels in the fifties and why is that detrimental?

[Rodders53]

NO --- oh you already have done.... ;-)

The 180kW digital erps (170 on COMs a bit later, as they don't increase immediately) are approximately 1/20th of the analogue peak erps (1000kW or 1MW, if you prefer) and are designed to offer similar coverage to the analogue and is likely to be slightly better, rather than worse.

Re-using the analogue frequencies for the PSBs final digital, as they are doing, should help this.

As the analogues do not currently give overload problems then when they disappear and are replaced by higher power digitals there is no reason for them to cause any issues with amplifiers then.

All group A aerials should be fine for the PSB muxes. All should need to be changed for reception of the COMs. Any aerials installed to get the existing digital service should already be wideband and suitable for the new arrangemants.... {although ch21+ reception - the HD mux - might be an issue with some aerial response curves, C4 analogue reception - on ch21 - ought to checked by viewers now - before it's too late to do so}.

The DSO transmission powers, frequencies and transmitting aerial patterns have been planned very, very carefully you know.

[Boostrail]

Originally Posted by Rodders53

As the analogues do not currently give overload problems then when they disappear and are replaced by higher power digitals there is no reason for them to cause any issues with amplifiers then.

My experience is that the accepted difference between a minimum and maximum acceptable signal is far less on digital than it was on analogue. I have already encountered one instance where nearer to the Tx the digital signal even pre DSO was problematic due to a too high signal whereas their TV's analogue tuner handled the enormous potential analogue over signal without difficulty!

Originally Posted by Rodders53

All group A aerials should be fine for the PSB muxes. All should need to be changed for reception of the COMs. .

I think this is a somewhat sweeping statement in respect of the COMS. I think it is dependent on location and distance from the Tx. I think lets wait and see and re-assess after April 13th

[Boostrail]

First stage is tomorrow- does anyone know what time?

[pault2007]

Originally Posted by Boostrail

First stage is tomorrow- does anyone know what time?

6am and same time on the 13th April - according to this site:

Digital UK - Relay transmitter switching times


Do we just need to do a full channel scan once tomorrow and can we do it at any time?

Will Freeview HD be available from tomorrow (I've bought an HD box)?

[Boostrail]

Thanks for that info re time pault2007.

As I understand it a fulll channel scan is recommended although only one Mux moves on to the (BBC2) vacated Ch27.

The bigger changes occur on April 13th when the HD multiplex also starts so 14 days 10 hrs 27 minutes to go!

[Boostrail]

Thinks - I must watch some analogue BBC2 tonight - end of an era.

I lived in London when BBC2 started. It was the first 625 line -576i in todays speak (and the first UK TV on UHF but still monochrome ) service in the UK. 1963 I think. The launch night was postponed to the following nght due to a massive power failure in the whole of London caused by what I cannot rememberl

[pault2007]

I fully expect to see the last ever analogue BBC2 programme on YouTube tomorrow morning (or at least bits of it).

I'm a bit gutted that I've got to wait another 2 weeks for HD to start - just hope my little 26" LCD makes it worth it.

[Boostrail]

Originally Posted by pault2007

I fully expect to see the last ever analogue BBC2 programme on YouTube tomorrow morning (or at least bits of it).

I'm a bit gutted that I've got to wait another 2 weeks for HD to start - just hope my little 26" LCD makes it worth it.

I use VM+HD on my main lounge TV so have had the benefit of HD on many channels for well over a year. However have bought a Freeview HD box to go with the bedroom (full HD) 22" LCD TV - will be interesting to compare with HD on (bigger) lounge TV (Also full HD)

[Ray Cathode]

The PSB muxes at Sandy do not reach full 180kW power until 2012 after the last retune.

Source Digital UK postcode search for aerial installlers.

[Boostrail]

Originally Posted by Ray Cathode

The PSB muxes at Sandy do not reach full 180kW power until 2012 after the last retune.

Source Digital UK postcode search for aerial installlers.

I agree thats what it says however it is obvious that the new (This morning) PSB multiplex on C27 is at an enourmously higher power than the previous BBC multiplex . I found this morning that I get a perfectly stable picture on this multiplex on a 2 metre length of aerial cable with no aerial on the end .

(After retuning my kitchen TV I decided to re route the aerial cable and disconnected it from the wall socket.To my amazement the picture continued on the TV as if nothing had happened. I thought at first that maybe I was acting as an aerial so I dropped the lead on the floor - could still watch BBC1/2 etc! Kitchen is on ground floor on side of house furthest from Sandy Heath. The house is 25km from Sandy Heath and at sea level near a river.)

[Tuddy]

Daughter's BUSH TV managed to pick up 28 TV channels using our ancient roof-top aerial today (at last). Been using 4 Sky digiboxes around the house including the HD box on main set for ages now.

Managed to receive "Yesterday" but not ITV, Channel 4 or 5, will these come on the 13th?

[Fen Star]

Originally Posted by Tuddy

Daughter's BUSH TV managed to pick up 28 TV channels using our ancient roof-top aerial today (at last). Been using 4 Sky digiboxes around the house including the HD box on main set for ages now.

Managed to receive "Yesterday" but not ITV, Channel 4 or 5, will these come on the 13th?

I re-tuned about 12.15am and managed to get 28 channels none of the main ones but did it again at 8.00am and it found 128 channels all of my channels are back including the ones you listed above so you should have them now as far as i know...

[Tuddy]

Tuned the TV at about 5pm. The aerial is old (at least 20 years). The rf is sent via a 4-way booster, this was done so the original Sky could be viewed else where in the house.

Her's is the only set with Freeview built in. I'll give it another try at the weekend then on the 13th.

[nwgarratt]

I posted this elsewhere but has anyone got stuttering on the BBC channels?

Sandy Heath and BBC

[tvnightmare]

Digital BBC1 and BBC2 were rock solid before switchover (although ITV and CH4 have been unwatchable on occasion). I'm getting the odd artifact since switchover - and my TV shows a reduction in signal strength, which was in the high 80's - now varies between 60 and 70.

I thought power was supposed to increase after switchover, but that doesn't seem to be the case. Will this happen in two weeks time? I live in a flat and have been at odds with the managing agent since ITV and CH4 have been bad (and no cable, not allowed a satelite dish...) and have been waiting for switchover to help, but it seems that wait was in vain. Unless the power is yet to be increased.

[nwgarratt]

I have been getting reduced signal on BBC too. Quality was between 7 and 8 and now it is 5-7. It takes a drop to quality 5 to get picture problems.

[figrin_dan]

Can you check that you are actually getting the Mux from Sandy (C27) and not one of the relays (C62)?

[nwgarratt]

Originally Posted by figrin_dan

Can you check that you are actually getting the Mux from Sandy (C27) and not one of the relays (C62)?

I get CH27 as manually tuned to it. I will try again after the second stage and see if it works. The Inverto PVR and the Sagem digibox are fine so they will get used instead for the moment.

[ozzyngage]

Receiving BBC Mux A on CH27 perfectly in Ryhall, nr Stamford even though the aerial on the roof is pointing to Waltham.

The Waltham retune on the same day prioritised BBC TV services from Waltham but the BBC radio services from Sandy Heath.

It will be interesting to see what happens when Belmont goes full power as I already get a weak Mux 1 on CH30 (these channels get stored in the 800s).

[D_A_R]

Currently getting pixilation, picture freezing and squeaks on BBC1 and 2 have complained to Digital UK to be told I may need an attenuator. Is anyone else having these problems?


Thank you for your email dated 2 April regarding TV reception.


Your postcode is PE28 4BQ which means you are likely to receive your TV signal from the Sandy Heath transmitter in the Anglia TV region Your local BBC news service therefore should be Look East and Anglia Tonight for ITV. This transmitter completes switchover on 13 April 2011. Any digital equipment that's attached to an aerial will need to be retuned on that date.

If you have an aerial amplifier or splitter booster this could be the cause of the problem. An aerial amplifier should only be used in poor digital TV reception areas. Signal boosters will not improve TV reception in strong signal areas, nor will they help reduce analogue TV picture ghosting. When an aerial amplifier is used in a good TV reception area it only serves to increase the likelihood of experiencing television interference and worsen the overall quality of reception. If you do have an aerial booster please remove it in the first instance.

The transmission power for some channels from the Sandy Heath transmitter was boosted as part of the switchover process, and it may be this that is causing your problem. With this type of problem you may be experiencing freezing, clicking and blocking with you reception, as your signal maybe too strong for your digital equipment to handle.

If the problem persists, you may require an attenuator, which is a small device that fits onto the coaxial plug that goes into your digital equipment and weakens the signal. We would advise that you wait until switchover is complete before taking any action to see how the situation develops. Once switchover is complete, if the situation is not resolved, it may be an idea to get further advice from a local trusted TV engineer or registered Digital Installer. You can search for a Registered Digital Installer in your area at their web site.

If you have any further enquiries regarding the digital switchover please visit our website at Digital UK - Home or call us on 08456 50 50 50.

Kind Regards,

Jim Davidson
Digital UK

[tvnightmare]

I don't think Cambridge gets it TV signal from the madingley relay - that is just channel 5 and FM radio, if I'm not mistaken.

I'd like to know if this is true - whether Sandy Heath is now broadcasting BBC1/BBC2 on full power. Does anyone know for certain? If so, why has it resulted in a weaker signal? I'm guessing it is the switch to 64QAM. If it is, I need to get the aerial sorted somehow - living in a flat with the cheapest coax in the wall and managing agents that just shrug their shoulders is not good....

[figrin_dan]

The BBC1/2 mux is certainly on much higher power than previously. Unfortunately, it has moved to another band and is jammed between the analogue signals. I would wait for a couple of weeks to see what happens after the remaining analogues are switched off.

[Boostrail]

Over on Digital Spy there is a poster who is receiving PSB1 (C27) in fair weather from Sandy in Lincoln! Thats about 85 miles away!

BTW I think it is possible that some people are confusing signal strength with signal quality which could go down if the signal is too strong. It depends on what a given DTT tuner displays.

I think we will see a number of people who live upto 20-30 miles from the TX and who were sold large "digital" aerials pre- DSO experiencing "over signal" problems.

[Boostrail]

Originally Posted by D_A_R

Currently getting pixilation, picture freezing and squeaks on BBC1 and 2 have complained to Digital UK to be told I may need an attenuator. Is anyone else having these problems?

I think this is probably right - you are it appears approx 8 miles from me and I believe you are on quite high (for round here) ground with probably a virtually clear line of sight to the Sandy mast about 16 miles due south of you. Have you recently had an aerial upgrade or do you have an original group A aerial?

If you were using an aerial amplifier for freeview then remove it from the system.

Otherwise as has been suggested wait until the 15th and see what happens after re-tuning then.

But one of these may be necessary?

[smjxm09]

Originally Posted by D_A_R

Currently getting pixilation, picture freezing and squeaks on BBC1 and 2 have complained to Digital UK to be told I may need an attenuator. Is anyone else having these problems?

Sandy Heath is unusual as not all of the muxes will be increasing power when the rest of the analogue stations are switched off next week. If you fit an attenuator this could have an effect on signal strength and quality on those muxes that will not increase power for another year.

As I side issue I have 7 TV's. 6 scanned OK while I had issues with one TV as it kept locking into London with its very week BBC signal. It got there in the end but it took several attemps.

[D_A_R]

Thanks Boostrail,

All was fine pre DSO with digital channels - have high gain aerial and distribution amp for feeding several rooms so removing it not an option, will wait until 13 April for phase 2 of the DSO and then will try attenuator.

Whole DSO doesn't seem that well planned in engineering terms, other DSO areas have suffered in similar ways and standard answers from Digital UK are buy new kit or use an attenuator which isn't very useful

[Rodders53]

Originally Posted by D_A_R

Whole DSO doesn't seem that well planned in engineering terms,

That is your impression but I can assure you the planning has been executed in a highly organised an efficient manner....

Communication via DigitalUK is another matter (but that's what you get when you out-source).

other DSO areas have suffered in similar ways and

I don't think so... each area has had its own, unique, set of problems. Sandy Heath is most unusual in that after DSO the COMs are not in the old analogue (group A) aerial response.

standard answers from Digital UK are buy new kit or use an attenuator which isn't very useful

Amplifiers should really only be used as a last resort.
Some people out of the target service area of the 'original DTT' transmitters have gone with OTT aerials and amplifiers to get the service ... these may be likely to overload - where an attenuator (before amplifiers) may well be the correct thing....
Of course a truly professional installer should have issued caveats/warned the user at the time.

[D_A_R]

Rodders53 when a service worked well before full switch over then doesn't after full swith over it does not equal good planning in my view; and on many of the engineering projects I've worked on 'reducing the service' would not be acceptable to the customer who is paying the bill!

Do a search on here about DSO and pixilation you will find others who've had problems, I admit there are other reasons but some similar.

I use a Televes distribution amp which has worked well for several years. Great to suggest a 'professional installer' who will offer a service then caveat it!

I'll wait for full DSO to complete then try an attenuator. Thanks for the comments though!