Freeview: Crystal Palace (Greater London, England) Full Freeview transmitter
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Full Freeview on the Crystal Palace (Greater London, England) transmitter

Google StreetviewGoogle mapBing mapGoogle Earth51.424,-0.076 or 51°25'26"N 0°4'32"WSE19 1UE

4G at 800MHz (at800) Freeview reception issues

When 800MHz 4G mobile broadband services start there will be 3 multiplexes in the higher risk range (C21-23, C30, C59-60): C22: ArqA, C23: BBCA, C30: BBCB
See How do I know if the 4G broadband will overload my Freeview? and Full UK map of 4G issue areas for details.

This transmitter has no current reported problems

The BBC and Digital UK report there are no faults or engineering work on the Crystal Palace (Greater London, England) transmitter. Click to recheck

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The symbol shows the location of the Crystal Palace (Greater London, England) transmitter which serves 4,490,000 homes.

Other maps:Crystal Palace DABCrystal Palace AM/FMCrystal Palace regionBBC LondonLondon

Radiation patterns

Radiation patterns withheld

Map key

The bright green areas shown where the signal from this transmitter is strong, dark green areas are poorer signals. Those parts shown in yellow may have interference on the same frequency from other masts.


List by multiplex|List by channel number|List by channel name|See terrain plot

Crystal Palace transmitter Freeview broadcasts

If you have any kind of Freeview fault, follow this Freeview reset procedure first.

Digital television services are broadcast on a multiplexes (or Mux) where many stations occupy a single broadcast frequency, as shown below.

MuxAerial positionFrequencyHeightModeWatts
PSB1
BBCA
 horizontal max
C23 (490.0MHz)324m64QAM 8K 2/3
24.1Mb/s DVB-T MPEG2		200,000W
Channel icons
1 BBC One London, 2 BBC Two England, 7 BBC Three, 9 BBC Four, 70 CBBC Channel, 71 CBeebies, 80 BBC News, 81 BBC Parliament, 301 301, plus 12 others

PSB2
D3+4
 horizontal max
C26 (514.0MHz)324m64QAM 8K 2/3
24.1Mb/s DVB-T MPEG2		200,000W
Channel icons
3 ITV (London), 4 Channel 4 London ads, 5 Channel 5 London ads, 6 ITV 2, 13 Channel 4+1 London ads, 14 More 4, 28 E4, 33 ITV +1 (London),

PSB3
BBCB
 horizontal max
C30- (545.8MHz)324m256QAM 32KE 2/3
40.2Mb/s DVB-T2 MPEG4		200,000W
Channel icons
101 BBC One HD (England no regional news), 102 BBC Two HD (England), 103 ITV HD (ITV London), 104 Channel 4 HD London ads, plus 1 others

COM4
SDN
 horizontal max
C25 (506.0MHz)314m64QAM 8K 3/4
27.1Mb/s DVB-T MPEG2		200,000W
Channel icons
10 ITV 3, 20 G.O.L.D. (not free), 25 Dave ja vu, 26 Home (not free), 27 ITV 2 +1, 30 5*, 31 5USA, 34 ESPN UK (not free), 38 Quest, 39 The Zone, 44 Channel 5 +1, 72 CITV, plus 22 others

COM5
ArqA
 horizontal max
C22 (482.0MHz)321m64QAM 8K 3/4
27.1Mb/s DVB-T MPEG2		200,000W
Channel icons
11 PICK TV, 12 Dave, 17 Really, 29 E4+1, 32 Movie Mix, 46 Challenge, 48 Food Network, 82 Sky News, 87 Community Channel, plus 9 others

COM6
ArqB
 horizontal max
C28- (529.8MHz)321m64QAM 8K 3/4
27.1Mb/s DVB-T MPEG2		200,000W
Channel icons
15 Film 4, 18 4Music, 19 Yesterday, 21 VIVA, 24 ITV 4, 41 Sky Sports 1 (not free), 42 Sky Sports 2 (not free), 47 4seven, 83 Al Jazeera English, 85 RT English , plus 21 others



Regional news from the Crystal Palace transmitter


BBC London 4.9m homes 18.4%
from London W1A 1AA, 11km north-northwest
to BBC London region - 55 masts.

ITV London News 4.9m homes 18.4%
from London WC1X 8XZ, 11km north-northwest
to ITV London region - 55 masts.

Self-help relays

Charlton AthleticTransposerRedeveloped north stand Charlton Athletic Football Club130 homes
DeptfordTransposersouth-east London100 homes
GreenfordTransposer12 km N Heathrow Airport203 homes
HendonTransposerGraham Park estate50 homes
White CityTransposer9 km W central London80 homes

How the transmission frequencies change over time

years1950s~851984-971997-981998-20122012-132013-182013-18
aerial groupVHFA KA KA KA KA KA K
C1BBCtv
C22-2ArqAArqAArqA
C23ITVITVITVBBCABBCABBCA
C25-1SDNSDNSDN
C26BBC1BBC1BBC1D3+4D3+4D3+4
C28-B-ArqB-ArqB-ArqB
C29-Dlocal
C30C4C4C4-BBCB-BBCB-BBCB
600C32-A
C33BBC2BBC2BBC2com7
C34+C
C35com8

orange background for multiplexes names moregreen background for transmission frequencieslilac background for power levels in watts800MHz band: 4G mobile to start in 2013700MHz band: possible 4G in 2019 more600MHz band: new or moved digital TV services more
Notes: + and - denote 166kHz offset; aerial group are shown as A B C/D E K W
Italics for analogue, digital switchover was Wednesdays 4th April and 18th April 2012.

  • Ofcom have projected that a local television service for London including Greater London area could use an Interleaved Frequency on the Crystal Palace transmitter using C29
  • COM7, COM8 projected for 2013-16. COM7 and COM8 to operate as Crystal Palace,Guildford, Reigate SFN.

Comparison of old analogue and current digital signal levels

Analogue 1-4 1000kW
SDN, ARQA, ARQB, com7, com8, BBCA, D3+4, BBCB(-7dB) 200kW
Mux 1*, Mux 2*, Mux A*, Mux B*, Mux C*, Mux D*(-17dB) 20kW
PreDSO-BBCB*(-20dB) 10kW

History of Channel 3 in the Crystal Palace transmitter area

Sep 1955-Jul 1968Associated-Rediffusion†
Sep 1955-Jul 1968Associated TeleVision◊
Jul 1968-Dec 1992Thames†
Jul 1968-Dec 2014London Weekend Television♦
Jan 1993-Dec 2014Carlton†
Feb 1983-Dec 1992TV-am•
Jan 1993-Sep 2010GMTV•
Sep 2010-Dec 2014ITV Daybreak•
• Breakfast ◊ Weekends ♦ Friday night and weekends † Weekdays only. Crystal Palace was not an original Channel 3 VHF 405-line mast: the historical information shown is the details of the company responsible for the transmitter when it began transmitting Channel 3.


Your comments: most recent posts are at the bottom

firstFirst comments prevEarlier comments  ◊  Later commentsnext Latest commentslast

Your comments are always welcome. Please use the form below to add your thoughts or questions to this page. We will get back to you as soon as we can.

Tony
Tuesday 8 May 2012 7:26PM Chelmsford
jb38: Sorry. I should have mentioned that I live in Chelmsford, CM1 6SS. Thank you for your comments.

I have a Horizon HDTM meter and it is showing a signal increase of about 3db (from ~27db to ~30db. I had been expecting a greater increase than that.

I have a 0-20db attenuator built into my system. Do you have an optimal db value in mind?

Thanks in advance. I'll get back to you to report my findings.

Tony
Tony
Tuesday 8 May 2012 10:31PM
jb38: I tried attenuating my input signal and the HD channels immediately froze and came back when I reduced the attenuation to zero.

Am I right in thinking that the signal is not overloading? Maybe I need a better aerial for HD?

I have had my current setup for over three years.

Tony
jb38
Tuesday 8 May 2012 11:47PM
Tony: If your meter is HT-DM Plus then that wont respond to DVB-T2 signals, so its a bit strange why you see anything being indicated.

You are located at 34 miles away from Crystal Palace and 21 miles away from Sudbury, and although its about 40 degrees out from the rear pick up of your aerial it would be interesting to know the result if you tried a manual tune test on Sudburys HD transmitter, this operating on mux Ch47.

A little point I did wonder about though was, that when you had originally reported that the SD quality was indicated as about 100% or so, what was the signal strength seen associated with that quality? as sometimes if a signal being received is of a very stable nature then the actual strength of the signal can be quite low, and should this be applicable in your case then it might be on the verges of being too low for reliable HD reception, just like a signal on the opposite end of the scale (excessively high) will always cause problems on HD before SD, so strengths as well as quality has to be known.

What you have mentioned about you aerial might well apply, but the only real way for anyone to verify if their aerial system can be excluded from being the cause of a problem is by trying another TV on it, as PC card tuners and indications obtained from same tend to be a bit non-standard and therefore the readings obtained cannot be used for assessment purposes in exactly the same way as done with normal TV or boxes tuners.

If you have the type / model of tuner card fitted in the WMC maybe you could give an update on this.
jb38
Wednesday 9 May 2012 12:07AM
Big Mart; Well you have just about exhausted about every possible test that there is to try, although should the chance ever arise for you to try your DVD recorder out on someone else's aerial system I would love to know the outcome of the test, as I feel that your HD problem is caused by either your recorder malfunctioning when on HD, or that that the quality of the signal is defective as far as HD is concerned before reaches your flat, as it has to be one of the two.
Edward Horne
Wednesday 9 May 2012 10:01AM Braintree
CM7 1XT
I have a Humax 9200T, as of the 8th the picture is breaking up,
The signal detection before this date was a strength of 95% and quality of 80%.
These figure are now, strength 92% and fluctuating +2%, quality 40% and jumping randomly to 50, 60 100%.
As I say before the 8th and since tuning since the changeover everything has been fine.
Any suggestion?
Big Mart
Wednesday 9 May 2012 6:11PM London
jb38: I actually own a house in Portsmouth, which I maybe visiting over the weekend. I usually leave the recorder in London so that it can record programmes if I am out.

If I took the recorder down with me; it would presumably need to be retuned for the local transmitter. Would all the programmes that are saved on the recorder remain, and would any new programmes recorded down there, be viewable without problem in London.

The tv down there doesn't have HD, but I presume that is not a problem.

However with all the setting up there, and re-setting back here, I wonder if it is worth it ?!
Tony
Wednesday 9 May 2012 9:01PM
jb38: The plot thickens.

I would have explained earlier (I thought this issue was a simple one, wrongly), but I have a fairly complex setup. My aerial goes into a 0-20 attenuator and then into a Labgear 16 way destribution unit. Four of the outputs from the Labgear go to my WMC PC. Four others go to TVs throughout the house, three of which are HD ready, but don't have Freeview HD. Therefore, I get the HD from WMC extenders attached to my WMC PC (wired).

My Horizon meter shows channels 22, 23, 25, 26 & 28 having a signal strength of 30db. Using WMC I am able to see that all of these channels are giving signal qualities of 100%. As you say, the Horizon meter is no good for HD, so I can only diagnose that WMC reports the HD channel signal strengths are 60%.

WMC scans for channels by region (i.e. country) rather than by transmitter. So, when I setup the TV signal, WMC actually detects more than one source for certain channels. All but the Crystal Palace sources have inferior signal qualities. Where I live in Chelmsford, I get an unrestricted signal from Crystal Palace as I am quite high up with very few houses between me and the fall away of the hill I am at the top of. The aerial is setup to point slightly upwards of horizontal.

I have spoken to an aerial installer on the phone today and was told that the only way to be certain what might be wrong (if at all) is to do a survey. Sadly, they don't cover my area. So, I'll need to find a local installer (one I can trust as I've been stung before and am a bit wary now).

I hope this explains better my setup and how I am able to quantify the signal.

Thanks for your patience

Tony
jb38
Wednesday 9 May 2012 9:01PM
Big Mart: If you enter your 4 digit password and carry out a "full rescan" there is no danger whatsoever of you affecting anything you have already stored, and although the TV at your other property isnt an HD model it doesnt really matter anyway, as you will still be able to see the actual HD channel that the Sony is picking up / recording but with you only being able to view it in SD.

Of course it would have been more preferable if you could have managed to try some other HD device on your present aerial system as what you have suggested is a second best but is certainly "still" worth a try, as if it records glitch free then it points to the signal you are receiving at your present location being sub standard.

As far as your other property is concerned, although I dont wish to appear as being a tad pessimistic, but I take it you have been in the area since any switchover activities (if that is) have taken place? as if you havent, then it brings another variable into the equation as far as the signal strength at your other property is concerned, although if its a Freeview TV then at least this will enable you to assess the situation regarding reception.
Big Mart
Wednesday 9 May 2012 11:25PM London
jb38: I have been to the other property since switchover, and the television has been done.

However, since posting this, I can think of somebody only a few miles away from me that I could take it to. Although obviously not on the same aerial system, we share the same transmitter! (Don't know if his tv is HD - I doubt it!).

As I look up my street, the neighbours all seem to have Sky dishes. Certainly the ones that I know to talk to have dishes.
jb38
Wednesday 9 May 2012 11:42PM
Big Mart: It doesn't really matter where you can try the Sony so long as its on a different aerial system to that presently used, and if what you have mentioned is at all possible then all good and well and I would be most interested to know the outcome of your tests.

The other fact of you having mentioned that most other people in your street all seem to have Sky dishes can obviously be interpreted in two ways, as in most places where this is seen it can ring alarm bells insomuch that the area is one of bad reception, or of course that its just the case that Sky is favoured for reception, although in my experience its usually the former reason.



Alan Tuthill
Thursday 10 May 2012 9:58AM Reading
My mother lost reception of ITV and ITV+1 last night 9/5/12. Is it possible to trace what repeater this was coming from?

RG5 postcode
jb38
Thursday 10 May 2012 10:05AM
Tony: Having gone over everything you have reported and noting the info regarding the distribution amplifier etc given on your latest update, I would like you to try your Horizon meter connected directly onto the end of the aerial lead before it goes into anything, as although the 30db reading you have reported is quite capable of giving good reception it should really be quite a bit higher than this (45db+) to keep well above the reception threshold of the tuner, or the slight variations in signal levels that occur on a daily basis due to weather conditions etc can start to cause problems.

The other unfortunate aspect about your set up is that you do not have any way of checking the HD reception via the aerial system used except on your WMC card, and there isn't enough info around about this device (the card) regarding its performance to be able to assess certain aspects about its performance, like for example if its known to be stable on a channel that has a negative offset on its frequency such as applies with C/P's HD mux, this being why I enquired if you had tried to receive HD from Sudbury as it transmits bang on frequency.

If your Horizon is giving a reasonably accurate indication of the signal strength you receive then take the attenuator out of line, as rather than attenuate the signal it could benefit from a slight boost, so if you find that the signal level is higher directly from the aerial than when measured at the WMC, then for a test link the aerial directly onto the coax that's used to feed to the WMC, giving an update on results.

It would be interesting though to know what kind of results you would get if your aerial was directed towards Sudbury rather than Crystal Palace
TW15 1LU
Thursday 10 May 2012 10:57AM Ashford
Sirs,

I have found that the addition of a High Pass Filter, to ones aerial wire can vastly improve reception. It does this by cutting out the transmissions from cab radios, radio hams and generalUHF interference. Obviously, the signal strength reaching your TV is affected but inbuilt amplifiers can take care of that. A real pleasure to watch with one of these fitted.
jb38
Thursday 10 May 2012 12:33PM
Alan Tuthill: Go into the signal checking screen and observe the mux channel number thats shown associated with the strength / quality indication, if Ch26 its Crystal Palace whereas if Ch42 its Hannington, the only other alternatives are so low in level that its doubtful if they would be received.

By the way the BBC match for these channels is Ch23 (C/P) and Ch45 (Hannington).
Tony
Thursday 10 May 2012 8:05PM
jb38: Thank you for your detailed analysis of my situation.

I will try what you suggest and take the attenuator out of the system and measure the reading on the Horizon meter straight from the aerial. I have to say that, as you also suggest, I was expecting a much higher db reading after switchover since the wattage should have gone up to 200,000 watts. It occurs to me that the Horizon meter might be limited to what it can display - so I'll contact Horizon to ask that question.

To switch my aerial around to Sudbury I would need to get a tv engineer out and that is out until I establish the true state of affairs.

FYI, I am using BlackGold BGT 3620 cards in my WMC PC.

I'll get back to you when I have tested the points above. Sigh.....

Tony
Tony
Friday 11 May 2012 5:52PM
jb38: Okay. I think I've got the story straight.

Firstly, I've been abit of a klutz and was not reporting the correct signal category from my Horizon meter. What I should have reported is as follows:

Channel dbuv
22 56
23 59
25 60
26 62
28 63

These values, which are direct from the aerial, seem to be well over the value predicted by the 'UK digital TV reception predictor' which suggests the normal value to be 46. So, it looks like there is nothing wrong with my setup. I have now removed the attenuator and a couple of splitters I had in my system. The readings after the signal has been distributed by the Labgear splitter are as follows:

Channel dbuv
22 63
23 64
25 65
26 66
28 67

The SN readings from the Horizon meter are showing no errors.

I telephoned Horizon and spoke to a very helpful chap who indicated that HD reception will never give the same signal qualities as standard channels - he said that some meter manufacturers fiddle the signal scale for HD channels to make it seem that the signal qualities are the same for standard and HD channels. He thought that a signal quality for HD of 60% compared to 100% for standard channels is about right.

Does all this make sense to you?

Tony

Edward Horne
Friday 11 May 2012 6:07PM
I have now resolved the issue.
Starting on the 8th roadworks were started close to the property. The traffic signals put in place use radio signals between themselves to control their timing. These signals have been causing interference.
Transmitter engineering
Friday 11 May 2012 6:27PM
CRYSTAL PALACE transmitter - Over the next week Crystal Palace main transmitter: TV (digital) working normally, Radio (analogue) Possible weak signal, Radio (digital) working normally. [DUK]
Transmitter engineering
Friday 11 May 2012 6:27PM
CRYSTAL PALACE transmitter - Over the next week Crystal Palace main transmitter: TV (digital) working normally, Radio (analogue) Possible weak signal, Radio (digital) working normally. [DUK]
jb38
Friday 11 May 2012 9:42PM
Tony: Well unless you have the HTDM-T2 version then what he has told you doesn't really make sense, because unless I am mistaken the older HTDM or plus types should not respond at all to an HD signal, this in the same way as applies with all standard Freeview receivers, insomuch that if you try to manually tune in an HD channel and the device you are using only has a DVB-T tuner (SD) then the result will be a "no signal received" message even although the HD signal might be belting in.

The other point is, that I was doing some checking on the BGT 2630 and discovered that there are a number of issues with it for a variety of reasons and with mostly all concerning HD, a users comment seen on the link (below) referring to an offset frequency having to be manually entered for HD albeit this action not being necessary for SD, I didn't go into it in detail but its the fact that it was mentioned at all that's important.

With the new found knowledge of the problems some people experience when using that card it somewhat reinforces what I had previously mentioned insomuch that you are assessing performance purely on what you see with the card, and so its essential for your HD signal to be tested on a more standard device other than this (e.g: a Freeview HD box etc) as you could be spending no end of time trying to compensate for something that's caused within either the PC card or the PC circuitry itself.

By the way, these updated signal readings you have given are very much better and indicate indicate perfectly OK, especially the aspect of zero error rate, cant beat that!

These are only two examples of what was seen mentioned. (you will likely have to copy and paste them into the browser)

experts.windows.com link icon 
Windows Experts Community


An original review referring to minimum specs for PC's etc when using the card.

www.techradar.com link icon Black Gold BGT3620 review | from TechRadar's expert reviews of Tv tuner cards
Tony
Sunday 13 May 2012 7:42PM
jb38: Thank you, again, for a detailed response.

I don't have a HDTM-T2 monitor and I cannot check the HD signal strength except by using what WMC reports. The Horizon expert indicated to me that I should not expect a signal quality of 100%, as, he says, no-one will get that for HD for freeview terrestrial. I cannot comment on whether or not this is really so.

The issue you mention about the BGT3620 card isn't as problem with the card but a 'feature' of WMC for Windows 7 where WMC scans and loads channels from multiple transmitters. This means that there may be several sources for each channel. It then is necessary to manually remove all sources that reference frequencies for transmitters that you don't wish to use. This process is incredibly tedious. As it happens, I am a .NET developer and have written a windows application to manage this issue very easily - it removes all sources whose signal quality falls below a user defined threshold in less than a second. So I have overcome this issue.

Anyway, the main thing is that I do appear to be getting a better than adequate signal from Crystal Palace and do not need to call in a TV engineer.

Thanks for all your help.

Tony
NICK ADSL UK
Sunday 13 May 2012 9:23PM
Tony the only experts are the ones like JB/mike.Brian/and myself having said that my expertise is a little different in i know a duff storey if i was told one and regretfully you have been told one

I get a 100% for quality and strength as that's what I'm about as a person always going the extra mile to perfect something just like the old Japanese days

Sadly today thou those days are over but none the less i still aim for perfection in everything i undertake

Mike Dimmick
Monday 14 May 2012 6:44PM
Tony: It depends whether the device is reporting error counts (or 100% less error count) before or after the two stages of error correction. Most Freeview boxes, and PC cards, report quality statistics after both stages of error correction and are therefore completely useless for setting up for best reception.

The HD-TM does show pre-Viterbi error rates and an indication of carrier-to-noise ratio. You should adjust your system to minimize the pre-Viterbi BER. Before switchover it was generally recommended that you should keep digital signals in the 45-60 dBuV range, after switchover you can probably add a bit more headroom (this range was recommended to keep the *analogue* signals, typically 10-20 dB louder than the digital ones, in the 60-80 dBuV recommended range.)

TVs, boxes, tuner cards and dongles usually don't display pre-Viterbi statistics as the decoded signal has to be re-encoded to compute them, which requires extra logic.

Raw bit error counts for HD signals will be greater than for SD signals, because the HD mux carries approximately 66% more data. Still, they should be about the same order of magnitude. They're more normally quoted as rates, number of bits in error compared to the total number of bits, which should be about the same.

Be aware that BER is quoted in exponential notation and it's a very small value. A larger exponent (the value after the E) is *better*, not worse. 1E-4 is 1 in 10,000, 1E-6 is 1 in 1,000,000. "Quasi-Error-Free" is given in the DVB-T spec as a figure of 2E-4 *after* Viterbi decoding (i.e. post-Viterbi).

I'm not sure which predictor you're using. Digital UK is the only one I know of that uses correct data (mainly because the broadcasters are the only ones that have all the necessary data) and correct algorithms. Digital UK's figures are percentage of locations within your grid square that are expected to have sufficient margin for 99% of the time (50% for the second column), they are not field strengths or terminated voltages. Wolfbane is widely considered to give results that are too low; even so, the predicted values given are electric field strength in dBuV/m, not terminated voltages in dBuV. The conversion is related to the aerial's dimensions and gain.
Tony
Monday 14 May 2012 7:21PM
Nick & Mike: Thank you for your comments.

Like youselves, I am also a bit of a perfectionist (which drives my better half mad). My current Horizon meter seems to be showing that my SD reception is execellent, but in signal strength and quality. The only issue is whether or not my HD reception is optimal. But I don't see how I will be able to prove that without spending a fair amount of dosh getting a HD-T2 meter. The trouble being that once I've established the facts, the meter will be redundant.

The alternative is to get a TV engineer in, and I've been stung doing that before....

Tony

jb38
Monday 14 May 2012 9:18PM
Tony: I really do think that rather than taking the in-depth analysis approach as to the possible causes of your complaint and maybe being tempted to spend no end of money as well as frustration in the process, that the reason for your problem would be discovered a lot quicker if you managed to borrow either an HD box or an HD capable (DVB-T2) TV and checked the results from your aerial system using one of these devices, because I have a sneaking suspicion that you are not really willing to consider the possibility that the problem could be caused by the card, and likewise are looking for reasons that excludes it, albeit I do accept that there is a very slight possibility that it might not be!

And with regards to the PC card, I do realise that issues existed between the WMC and the card, but I am referring to other aspects concerning comments seen made in various sources regarding the actual tuners performance including its ability to cope with an offset in the frequency of whatever its trying to tune in, as software wont necessarily help with that type difficulty any more than it does in a range of the older Vestel chassis Freeview PVR devices, with the results of a software upgrade in these devices being totally hit and miss, because the problem is more one of a hardware circuitry nature caused by a PLL oscillator with a semi rigid AFC range.
Tony
Tuesday 15 May 2012 7:58PM
jb38: This strand really got going because I was wondering why WMC was reporting HD channels as having a signal quality of 60% when all of the SD channels were 100%.

I am committed to providing digital tv to all rooms in my house from a single source. This allows us to be able to watch our recorded tv programs from any room in the house as well as live HD tv without having to replace all of the televisions.

Based upon your suggestions, if there is a problem with the video cards, then I will just have to live with that until a better card comes out.

Hope this thread hasn't been a complete waste of your time and much appreciate your comments and those of other contributers.

Tony
Gareth
Friday 18 May 2012 1:42PM
Where is the Deptford self help relay located? What channels does it use?
Dave Lindsay
Friday 18 May 2012 2:11PM
Gareth: According to mb21, it is located at TQ374776.

This resolves to the junction with Creek Road and Deptford Church Street. Other than that, I haven't found any information online as to what channels and polarisation it uses.

Perhaps Ofcom could advise you.
Gareth
Friday 18 May 2012 7:57PM
Thanks Dave. I will investigate with a pocket DVB -T set next time I am over there.
Mike Dimmick
Wednesday 30 May 2012 6:10PM
Dave Lindsay, Gareth: Don't assume that the grid reference is accurate! All Ofcom's document says for the location is 'south-east London' and that it targets 100 households. Some of the grid references on MB21 are accurate, but only because someone has been out and found the site already (in which case it's probably been photographed).

The final Installer Newsletter for Crystal Palace ( www.digitaluk.co.uk link icon http://www.digitaluk.co.u….pdf ) stated that Deptford was still active at the time of writing, but that they had not yet decided whether to apply for a digital licence.

It was listed as a transposer in Ofcom's guide, which means it uses different channels from those used by Crystal Palace. The other sort of relay is an Active Deflector, which uses the same channels.
jol
Friday 1 June 2012 10:47AM
Hi,can anyone help me.
I have a wharfdale pvr connected to arial in attic.
Before digital switch over the analog picture quality was poor but the digital picture quality was crystal clear.
After the switch over the digital quality is poor
strength and quality ratings are both at 8

Any ideas ?
David
Saturday 2 June 2012 11:34AM Reading
RG1 7JR. roof aerial
point to crystal palace
why do I get BBC South,and ITV for London. Not a big issue, just curious about getting two different regions from one transmitter, also why is hannington signal so weak at thia area
Thanks
David
Saturday 2 June 2012 11:36AM
How do I subscribe to the top up tv option on freeview,what exactly is it anyway...
Thanks
Dave Lindsay
Saturday 2 June 2012 12:24PM
David: You are not getting two different signals from one transmitter. You cannot be getting BBC South from Crystal Palace because it broadcasts BBC London!

If the BBC South signal is coming from Hannington (the signal strength screen will say it is tuned to C45), then run the automatic tuning scan and unplug the aerial when it gets to 30%. This will have the aerial plugged in for Crystal Palace and unplugged for Hannington and a few other transmitters that "may perhaps" be available to you.

Looking around the streets on Streetview there are quite a few aerials on Hannington, so you may be able to get it if you want BBC South and Meridian.

Failing that you may be able to pick up from Hemdean, which is a relay of Hannington, although it doesn't carry the Commercial channels. A way round this may be to combine the Crystal Palace aerial with a Hemdean one or if you can receive from Hannington directly, you could always retain your CP aerial and combine with a Hannington one to give you BBC South, ITV Meridian, BBC London, and ITV London.
Dave Lindsay
Saturday 2 June 2012 12:39PM
David: From what I can see on the map, you're a little low lying of Burghfield Hill. The trees beyond there look to be in the line between the transmitter and you and they appear as if they may be on the brow of the hill over which the signal comes. If so, then they are probably a detriment to your reception.

Those living in the valley in which the Thames runs also look to be affected with regards poor to non-existant reception from Hannington. This probably explains why Hemdean transmitter was built.

You are of course near to the Kennet, so that explains why your area might not be so good.
Dave Lindsay
Saturday 2 June 2012 12:44PM
David: One other thing to point out is that Hannington's Commercial multiplexes (known as "COMs") are not as strong as the Public Service Broadcaster (PSB) ones. Hemdean relays Hannington's PSBs, but does not transmit the COMs.

So you may find that you can receive Hannington's PSBs but not its COMs. If you are unable to receive Hannington's COMs, then its PSBs are also available from Hemdean (as it is a relay).

If you combined the Crystal Palace aerial (assuming that you can receive CP's COMs), then you will be able to watch Hannington's PSBs and the COMs.


For a list of multiplexes, see this page under the heading "After switchover configuration" (you may need to refresh to see the graphic):

www.ukfree.tv link icon Freeview multiplexes | ukfree.tv - independent free digital TV advice

BBCA, D3&4 and BBCB are the PSBs and SDN, ArqA and ArqB are the COMs. BBCB is the HD multiplex.
Robert
Saturday 2 June 2012 3:45PM
Does anyone else consider that Crystal Place now has an ‘insidious’ intermittent transmitter problem for people very local to the transmitter? Their Freeview reception can go totally to pot when the transmitter mast gets wet. And this is a new phenomenon post 4th April BBC and 18th April the rest. How much does anyone, world wide know about the behaviour of the multiplexers run at higher power. What changes were made to the configuration? How well is the science understood? How much field testing was done? I have had the very sensible suggestion of using attenuation which I have experimented with. But I also have noted a steady drop off signal powered as measured by my hard disc recorder, over the weeks since 4th April 2012. A few days latter after purchasing new aerials and attenuators, I thought the signal power measurement did not work, because it was always 10, even with 18dB of attenuation. It was only when I tried an unterminated VCR RF lead that I got a reading of 6. A few weeks later when I froze my configuration and stopped trying to find a new sweet spot for my new indoor aerial, as I had come to the inescapable conclusion the fault was outside of my equipment, I ran for a while with 12 dB but have reduced to 6 and then 0 in response to the measured power levels and continuing problems. Seven people or 100% of the people I talked too who use broadcast Freeview; in my block have noticed a decline in reception quality. 5 have the same insidious fault where TV can become unwatchable since DSO. Lots of indoor aerials and two independent communal aerial systems now longer are reliable for Freeview. After over 50 years of successful broadcast from Crystal Palace, TV is no longer a wireless device in this area. How can you watch a film error free for 2 hrs and the reception become totally unwatchable just at the climax of the film? Our communal aerials would be condemned in an eye blink because of their age according to DigitalUK. UK TV is not designed to be received by anything but an outdoor aerial here lots of people use a bit of wire, coat hanger or nothing, It gobsmaked the engineer who was doing the pre tune for channel 5 that all these TVs worked and on my post DSO survey I found a lady who uses Freeview and still has no aerial. The advantage of digital transmission is that with error correction, noise and interference can be filtered, Schmitt trigger circuits can clean up a digitally modulated analogue signal before it is converted back into in digital data all this help to make the medium far more tolerant and resilient but there are limits. Whatever is going wrong is far s beyond the scope of the signal processing and error correction circuits to cope with. Professional investigation is required. Any comments?
Robert
Monday 4 June 2012 1:05PM
What power did Multiplex BBCA on C23 start with on 4th April. 20 or 200 MW?

Does anyone, outside Arqiva know the detailed configuration changes to the broadcase antenna and if not being able to find BBCA on C23 was a resonable problem to have on an indoor aerial or not.

NICK ADSL UK
Monday 4 June 2012 2:28PM
Robert since switch-over my set up has been very bad despite all the equipment being of the highest spec one day on one day off and am told that's the way it's going to be in future by the BBC for some on Crystal Place

As for the reason the guy i was speaking to wasn't saying and i myself along with my tv field engineer have drawn a blank

I have freesat so this free view is no big deal but none the less would have liked it to work like is has done without fault from day one come switch over it's gone to pot
Robert
Tuesday 5 June 2012 12:58PM
NICK ADSL UK : Thanks for your posting. I might explain a bit of a ‘reluctance to engage’ I have felt from certain quarters. There is far far more to a problem of this type than the just technical issues. I was clueless to the scale of DSO and the technical risks taken. I’m very glad I’m not involved with any of the discussions and events that led up to DSO; however as an ex- European Technical Support engineer would love a bash at being part of the solution.
For a decade Freeview sometime took 30 minutes to set up and find a sweet spot for the indoor aerial, then it that was it, stable as a rock until I bought the next bit of AV kit and wanted to move stuff around.
Val Tilley
Friday 8 June 2012 2:09PM
For over 2 weeks, I have been unable to watch TV most of the time because of the 'pixeling'(?). Was OK once the final changeover took place, although Channel 12 does not even show on list. However, I have had to resort to watching on my computer and even that keeps giving up the ghost. Have re-tuned at least 4 times without success. Am not technically minded and would appreciate help in simple form!

Thanks
Mark Fletcher
Saturday 9 June 2012 12:44AM Halifax
Val Tilley.As you did not leave a full postcode or a nearby location as such,we cannot be of useful help to you !
NICK ADSL UK
Sunday 10 June 2012 6:48PM
Robert
as you may not know in that i am a Microsoft MVP who helps the world for free in the main forums in security

I post hundreds of security updates a year and the vast majority of the people in the world receive these without a problem but for some reason there are thousands more who run into a problem and i guess that free view is just the same all we can do at the end of the day is to help out the public the best we can and hopefully educate the public a little better so that they can understand on what's going on behind the scenes so that they realize that there not alone and free help is forthcoming
martyh
Sunday 10 June 2012 10:45PM
From martyh Ash Vale.

PICTURE PROBLEMS WITH FREEVIEW DONGLE.

Further to my postings regarding my digital TV and it being unable to use the new signal from April 4th, I purchased a scart plug in device (scart adapter) from Curry’s as suggested by jb38. It's a type that plugs in to a scart socket at the rear of my TV. However, I am extremely disappointed by the picture quality I'm getting and the fact that I have lost some part of the picture at the top and to the right of my screen. From the adapter remote menu, I would say that I’m, getting (on average) about 80% quality and 80% signal (variable). My pictures lack true depth of colour and can also be grainy. I have also noticed colour saturation problems (especially black and white in lack of definition, for example – no definition on suit lapels). I have tried adjusting elements such as sharpness, colour, contrast etc, using my TV’s menu without success. In addition, I have also tried altering between the RGB and CVBS modes on the adapter remote menu. When I switch between the two the screen options, the picture moves (flickers) to the left – like it’s offset. CVBS mode seems richer in colour but gives a less defined image, almost blurred. I have also selected combinations of 16:9 and 4:3, and combinations of these with the letterbox/full frame options. I have also tried several retunes, to see if that helps, to no avail, though I do get 115 TV and radio channels. Compared to the pictures I was getting on the 2k signal, direct through my TV Ariel into my TV, I am really not impressed with what I am seeing, especially as quality of pictures I now receive are actually straining my eyes. I thought the new format was supposed to be an improvement but it seems not. Any ideas. Please refer to my previous posts if you’d like to revise. Thanks! Martyh. Manual for my adapter can be found here: documents.knowhow.com link icon http://documents.knowhow.….pdf
ps.I have had my adapter for about 4 weeks.
Robert
Sunday 10 June 2012 11:06PM
Val Tilley: As a TV/Video amateur with a computer background what I understand is ‘Error’ Pixels or block on the screen start to appear when the block of data which make up the video audio stream come through with uncorrectable (unrecoverable) data errors due to too much noise or interference on the modulated UHF signal from the aerial.

Digital transmission is fault tolerant, you can have a degree of noise or interference but it has to be within the bounds of the error correction circuits. This is its greatest strength. Your tuner not only ‘knows’ the data is damaged but can correct it so the picture and sound generate are perfect so you never know but looking at the TV.

However, the fact the data had to be corrected is reported in the statistics used for either ‘Signal Quality’ or ‘bit rate error’. This is a feature most tuner have somewhere in their menu structure.

Missing channel 12 (Yesterday) probably means that your tuner failed to find one of the Multiplexers. Crystal Palace transmits all TV and radio over six multiplexers. To check I my tuner has found each one I should have BBC1 (1), ITV1 (3), ITV3 (10), Pick TV(11), Yesterday (12) and BBC1HD(50). Information on what TV station is on what Mux is explained elsewhere on the website but BBC2 shares with BBC1, ITV1 shares with Channel 4 & 5.

My recent experience with automatic scanning suggest that it is not very fault tolerant. The TV's tuner had a perfect picture yet the PVR which I was tuning missed the Mux. I was just manually tuning the Mux with ITV1 on it yet Channel 4 and Channel 5 were not in the list yet worked if I tapped 4 or 5 on the remote. So not very robust either.

Missing muxes are a common problem if you were setting up to watch Freeview via an indoor aerial but prior to DSO finding the sweet spot for the aerial was a 5 or 10 minute task once found it was reliable. I never knew there were seven muxes before DSO because I did not have to be able to diagnose reception problems before.
jb38
Monday 11 June 2012 8:30AM
martyh: Just to clarify a point insomuch that I did "not" recommend that particular brand of device to you, but had said that you should purchase a Freeview box or alternatively a Freeview adaptor and provided a link purely for reference purposes, the link being for a Konig brand device which is somewhat superior to anything with a Logic tag attached to it.

That said, have you went into this devices set up menu and selected settings to suit the TV you are using? this described on page 24, plus made sure that the same settings have been used on the actual TV? as your type of problem is usually caused by them having been set different to each over.

You have to also consider the other aspect concerning the level of Freeview signal you are receiving, as when your Philips TV stopped working after switch over this means that you will not be aware of the level of signal you are receiving from higher powered transmitters, and with neither myself or anyone else being able to assess this as you haven't provided a post code, or at least one from a nearby shop or pub, and a level predictor requires this info.

Maybe you could give an update on the aspects mentioned.
martyh
Monday 11 June 2012 11:35AM
From martyh GU12 Ash Vale Surrey/Hants

Hi jb38. Comments noted re Konig recommendation. If you read my previous posts, I did ask if it matters what make adapter was used, and had no reply, so thought any would do. No offence in my last post, as not blaming you on that. On settings, I have scart plugged into EXT1, and have selected this as my decoder on the actual TV settings. On the actual adapter remote menu have selected widescreen 16:9 (TV is widescreen), and full frame. Again, as per previous post have tried different settings on the logic and my TV menus to see if it makes a difference but it seems not to. The only thing I have not re-tried (again as it didn't seem make any difference at first set-up), is take an RF output from the logic to my TV Ariel 'in' socket. Re: signal levels. On the 2k signal pre April 4th (with Ariel plugged direct to my TV), I had 114 channels - all pulling in good pictures - and in full frame. However, built in to the TV there is a signal strength indicator, and for the most part it indicated signal strength to my location GU12 as always being poor - indication a red square, where red is poor, yellow good, and green excellent. Again, even so, I still got all the channels and very good pictures. Just to clarify that the Logic does have a signal quality and strength indicator, with bar type displays, and this is what I was referring to previously. As far as I can tell, I have unified both the Logic and TV settings. Hope this helps.
Steve
Monday 11 June 2012 2:11PM
I've been reading with interest the problems others are experiencing with their Freeview reception and it prompts me to ask a few basic questions:

First, I presume that transmitters are mounted on tall masts so as to ensure the signal emitted is presented with the least obstruction over the greatest possible distance - but what is the profile (shape) of the signal? Does it start off narrow and spread out wider with distance?

I note that several of the people with reception problems are quite close to the Crystal Palace transmitter and I understand that sometimes this might result in the signal they are receiving being too strong and requiring attenuation - but given the height of the mast, is it also possible to be so close to the transmitter that the signal passes over the top of a roof mounted aerial and hence misses it completely?

Finally, I live around 25 to 30 miles from CP and receive excellent freeview reception via an indoor aerial - obviously, the signal has to pass through the walls of my property - so why would something like leaves on a tree disrupt reception?
Thanks in advance.
NICK ADSL UK
Monday 11 June 2012 4:14PM
There's just one other thing that i have just come across in that all leads that go into equipment need to be of quality as most leads do have a habit of starting out OK but then if moved or touched losing the connection for some odd reason

So it's vital that you use leads of a high standard to rule this out
Mike Dimmick
Monday 11 June 2012 5:56PM
Steve: Signals from plain dipoles are diffused in a ring-doughnut shape. With more tiers of panels connected in-phase with each other, you get more gain in one plane and a number of additional smaller lobes. There are some angles that would indeed get no or nearly-no signal, referred to as nulls. The antenna designer therefore adds small differences in the lengths of the connections to each panel, which has the effect of reducing the nulls, at the cost of some efficiency. This is called 'null filling'.

Also, the main lobe of the transmitted signal would normally be exactly horizontal, which - due to the curve of the earth - actually misses the ground completely. Again, the changes to the relative phases allow this to be adjusted down a bit so that the peak signal lands at a reasonable point just short of the horizon - this is called 'beam tilt'.

Both null-filling and beam-tilt adjustment are performed to ensure that even those living very close will get sufficient signal. It will be less than the full 200kW, but people living this close do not need anything like that amount of power.

We don't have the design for the current transmitting aerial, but the BBC report for the old analogue aerial, with graphs showing its performance, is available at downloads.bbc.co.uk link icon http://downloads.bbc.co.u….pdf . The vertical radiation patterns are on p13-p15 (figures 10-12). One-tenth or one-twentieth of the field strength is still very high indeed, there are many local relays intended to serve areas 1-2km away from the mast that have less than 100W. There are transmitters with less than 2W output, indeed there are some 'Link' sites with less than 1W, although these are really to get the signal to another relay . People that close to CP are more likely to have too much signal than too little.

As for the leaves: I believe they're more effective at blocking radio signals at UHF than your walls are, because they're mainly water (even worse when wet leaves). They also move in and out of the path when the wind blows, making for a lot of additional variation.
jb38
Monday 11 June 2012 8:38PM
martyh: With regards to your query as to whether it matters what make of adaptor is used, I have to apologise for missing that posting and which on searching back I see was made on April 25th @ 7.41pm, although I would always advise anyone thinking on purchasing any digital receiving equipment to avoid the cheap end of the market, the Konig I used for an example not being as well as having a reputation for good performance, albeit of course as with all digital equipment there will always be someone with a problem.

However, on studying what you have reported I see its really a case of you having two separate issues, that of the picture ratio being incorrect plus that you cant find a happy medium when trying to balance out the colours etc on the TV. Your TV has four ratio modes 16:9 / 14:9 / 4:3 and Auto format, so what happens if you leave it on Auto and try a combination of settings on the logic? because to put it in a factual way a satisfactory outcome can only be achieved by experimenting with the setting options offered on the device as nothing external can be done to alter this.

This also applies to the issue of the colour / contrast / brilliance etc settings, as you really have to start afresh with these settings due to the fact that all of your original picture settings were made to suit the sets internal circuitry, and so just like as with the issue of the screen ratio a satisfactory solution has to (and can only) be achieved by experimenting with the settings offered on the TV, because this problem just like as with the picture format issue, can only be rectified via the range of settings offered on the TV's menu

That said, it would be of interest to know what kind of results would be achieved if you temporarily tried the Logic on another TV, as that would soon reveal if there was a problem with the device, as to me anyway, the quirks associated with particular Logic device is an unknown quantity.

Finally, regarding the aerial link from the Logic to the TV, you can really leave that permanently disconnected as you are in effect only using the TV as a monitor anyway.
Steve
Tuesday 12 June 2012 9:25AM
Mike, Thanks for your detailed explanations and answers to my questions - the null filling and beam tilting is most interesting - I guess there must be an optimum distance between the transmitter and the horizon where reception is just about right. Not too close and not too far. So neither attenuation nor booster needed.



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