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Full Freeview on the Sandy Heath (Central Bedfordshire, England) transmitter

first published this on - UK Free TV
sa_streetviewGoogle Streetviewsa_gmapsGoogle mapsa_bingBing mapsa_gearthGoogle Earthsa_gps52.130,-0.242 or 52°7'47"N 0°14'33"Wsa_postcodeSG19 2NH

 

The symbol shows the location of the Sandy Heath (Central Bedfordshire, England) transmitter which serves 920,000 homes. 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.

Are there any planned engineering works or unexpected transmitter faults on the Sandy Heath (Central Bedfordshire, England) mast?

Sandy Heath transmitter - Sandy Heath transmitter: Possible effect on TV reception week commencing 25/03/2024 Pixelation or flickering on some or all channels Digital tick


Choose from three options: ■ List by multiplex ■ List by channel number ■ List by channel name
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Which Freeview channels does the Sandy Heath transmitter broadcast?

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.

MuxH/VFrequencyHeightModeWatts
PSB1
BBCA
 H max
C27 (522.0MHz)291mDTG-180,000W
Channel icons
1 BBC One (SD) Cambridge, 2 BBC Two England, 9 BBC Four, 23 BBC Three, 201 CBBC, 202 CBeebies, 231 BBC News, 232 BBC Parliament, plus 16 others

PSB2
D3+4
 H max
C24 (498.0MHz)291mDTG-180,000W
Channel icons
3 ITV 1 (SD) (Anglia (West micro region)), 4 Channel 4 (SD) South ads, 5 Channel 5, 6 ITV 2, 10 ITV3, 13 E4, 14 Film4, 15 Channel 4 +1 South ads, 18 More4, 26 ITV4, 28 ITVBe, 30 E4 +1, 35 ITV1 +1 (Anglia east),

PSB3
BBCB
 H max
C21+ (474.2MHz)291mDTG-180,000W
Channel icons
46 5SELECT, 101 BBC One HD Cambridge, 102 BBC Two HD England, 103 ITV 1 HD (ITV Meridian Southampton), 104 Channel 4 HD South ads, 105 Channel 5 HD, 106 BBC Four HD, 107 BBC Three HD, 204 CBBC HD, 205 CBeebies HD, plus 1 others

COM4
SDN
 H -0.2dB
C33 (570.0MHz)291mDTG-8170,000W
Channel icons
20 Drama, 21 5USA, 29 ITV2 +1, 32 5STAR, 33 5Action, 38 Channel 5 +1, 41 Legend, 42 GREAT! action, 57 Dave ja vu, 58 ITVBe +1, 59 ITV3 +1, 64 Blaze, 67 TRUE CRIME, 68 TRUE CRIME XTRA, 78 TCC, 81 Blaze +1, 83 Together TV, 89 ITV4 +1, 91 WildEarth, 209 Ketchup TV, 210 Ketchup Too, 211 YAAAS!, 267 Al Jazeera English, plus 30 others

COM5
ArqA
 H -0.2dB
C36 (594.0MHz)289mDTG-8170,000W
Channel icons
11 Sky Mix, 17 Really, 19 Dave, 31 E4 Extra, 36 Sky Arts, 40 Quest Red, 43 Food Network, 47 Film4 +1, 48 Challenge, 49 4seven, 60 Drama +1, 65 That's TV 2, 70 Quest +1, 74 Yesterday +1, 75 That's 90s, 233 Sky News, plus 11 others

COM6
ArqB
 H -0.2dB
C48 (690.0MHz)289mDTG-8170,000W
Channel icons
12 Quest, 25 W, 27 Yesterday, 34 GREAT! movies, 39 DMAX, 44 HGTV, 52 GREAT! romance, 56 That's TV (UK), 61 GREAT! movies extra, 63 GREAT! romance mix, 71 That’s 60s, 73 HobbyMaker, 82 Talking Pictures TV, 84 PBS America, 235 Al Jazeera Eng, plus 18 others

DTG-8 64QAM 8K 3/4 27.1Mb/s DVB-T MPEG2
H/V: aerial position (horizontal or vertical)

Which BBC and ITV regional news can I watch from the Sandy Heath transmitter?

regional news image
BBC Look East (West) 1.0m homes 3.7%
from Cambridge CB4 0WZ, 29km east-northeast (65°)
to BBC Cambridge region - 4 masts.
70% of BBC East (East) and BBC East (West) is shared output
regional news image
ITV Anglia News 1.0m homes 3.7%
from Norwich NR1 3JG, 119km east-northeast (60°)
to ITV Anglia (West) region - 5 masts.
All of lunch, weekend and 80% evening news is shared with Anglia (East)

How will the Sandy Heath (Central Bedfordshire, England) transmission frequencies change over time?

1965-80s1984-971997-981998-20112011-1312 Feb 2020
VHFA K TK TK TW TW T
C6ITVwaves
C21C4wavesC4wavesC4waves+BBCBBBCB
C24ITVwavesITVwavesITVwavesD3+4D3+4
C27BBC2wavesBBC2wavesBBC2wavesBBCABBCA
C31BBC1wavesBBC1wavesBBC1waves
C32com7
C33SDN
C34com8
C35_local
C36ArqA
C39C5wavesC5waves
C43_local
C48ArqBArqB
C51tv_offSDN
C52tv_offArqA
C55tv_offcom7tv_off
C56tv_offCOM8tv_off

tv_off Being removed from Freeview (for 5G use) after November 2020 / June 2022 - more
Table shows multiplexes names see this article;
green background for transmission frequencies
Notes: + and - denote 166kHz offset; aerial group are shown as A B C/D E K W T
waves denotes analogue; digital switchover was 30 Mar 11 and 13 Apr 11.

How do the old analogue and currrent digital signal levels compare?

Analogue 1-4 1000kW
BBCA, D3+4, BBCB(-7.4dB) 180kW
SDN, ARQA, ARQB(-7.7dB) 170kW
com7(-13dB) 49.6kW
com8(-13.1dB) 49.1kW
Mux 1*, Mux 2*, Mux A*, Mux B*, Mux C*, Mux D*(-17dB) 20kW
Analogue 5(-20dB) 10kW

Which companies have run the Channel 3 services in the Sandy Heath transmitter area

Oct 1959-Feb 2004Anglia Television
Feb 2004-Dec 2014ITV plc
Feb 1983-Dec 1992TV-am•
Jan 1993-Sep 2010GMTV•
Sep 2010-Dec 2014ITV Daybreak•
• Breakfast ◊ Weekends ♦ Friday night and weekends † Weekdays only.

Comments
Thursday, 18 October 2012
Briantist
sentiment_very_satisfiedOwner

2:03 PM

Tim Newton: The model used on ukfree.tv is written by me, and is not that actual "UK Planning Model" because every time I have asked for it, I have been told it is a state secret, see Update on transmitter radiation patterns (BBC FOI request) | ukfree.tv - 10 years of independent, free digital TV advice for example.

The model used here on ukfree.tv is derrived from information provided by the OS, Ofcom and other bodies.

I am happy to provide anyone who wants it with the output of these calculations.

link to this comment
Briantist's 38,915 posts GB flag
T
Tim Newton
2:32 PM

Thanks for the prompt reply. Apologies for my mistake, the site referenced in the question was actually the Digital UK site. Sounds like you are struggling with the same bureaucracy as I am.

link to this comment
Tim Newton's 5 posts GB flag
Friday, 19 October 2012
Briantist
sentiment_very_satisfiedOwner

4:02 PM

Tim Newton: If you still want some data to work with, I can provide a dump for you.

link to this comment
Briantist's 38,915 posts GB flag
N
NJ
11:52 PM

I think I have solved my interference problem. Today I had fitted an A0968 28 element log periodic aerial, this replaced the 52 element HG10 WF aerial that was fitted. The improvement in reception is considerable. Although the gain of the new aerial is 4dB lower than the old one, the reception is greatly improved with no bit errors detected on any channel. I have to say the new aerial is mounted on a longer pole, putting the aerial 6ft higher above the roof top. But that said, it may now be necessary to turn down the gain of the distribution amp mux, as all Sandy Heath channel are at the top of the equipment signal strength range, close to overload on one of the DVRs.

Interestingly the new log periodic is smaller than the old aerial, and clearly offers a much lower wind loading.

What I do no understand is why the old aerial produced such poor reception only on one RF channel, channel 27.

link to this comment
NJ's 19 posts GB flag
Saturday, 20 October 2012
Dave Lindsay
sentiment_very_satisfiedPlatinum

12:06 PM

NJ: The reason why it only affected one UHF channel is probably down to the fact that they won't all be exactly the same. Had you had more gain, then maybe it would have started to affect other channels.

The is surely not to run it so high rather than wondering why one channel is degraded when others are not!

Digital reception requires good quality. Don't try to run it as close to full strength as possible.

With analogue, the stronger the signal the better the picture. With digital there is a threshold over which the signal can be received. Whilst it is a good idea to have a good margin over that threshold to allow for natural fluctuations, there is no need to strive for as high as you can as it gives no benefit to the picture.

link to this comment
Dave Lindsay's 5,724 posts GB flag
Saturday, 27 October 2012
N
NJ
7:35 AM

The argument that gain was the issue is clearly incorrect as my new aerial has a slightly lower gain than the old one and experiments were conducted using an aerial preamp that indicating front end gain was not a factor.

As I reported in my earlier postings, my receivers were all reporting high levels of signal, the problem was poor bit error rate.

The way in which the bit error rate changed with time of day suggested that the interferer was a strong reflection subject to Rayleigh or Rician fading.

Since the new aerial made such a difference, I can only conclude that either the old aerial had a notch in its frequency response due to an impedance mismatch problem, maybe the result of a poorly connected cable, which seems unlikely or the small increase in height and the slight change in aerial direction, was sufficient to mask the co-channel interferer. I will not know if the problem has been truly solved until we have experienced the full range of weather conditions.

Given the beam width of the old aerial is 32 degrees, the slight change in direction also seems unlikely to have resolved the problem.

It is worth note that the minimum front to back ratio of the new aerial is better than the old one, with large attenuation peaks across the band. A more complete comparison of the aerial specifications is impossible as the old aerial spec lacks the necessary gain plots.

link to this comment
NJ's 19 posts GB flag
Tuesday, 30 October 2012
S
Steve
10:59 PM

By the way the tuning problem with channels in 800s has resolved itself now. Dunno what that was about but not it seems my TV!

link to this comment
Steve's 4 posts GB flag
Saturday, 3 November 2012
S
steve
10:26 PM

Why can my internet tv receive meridian broadcast and get all the HD channels, yet my 5 other full HD tv's not receive 1 single HD channel between them from sandy heath?

link to this comment
steve's 2 posts GB flag
Dave Lindsay
sentiment_very_satisfiedPlatinum

10:38 PM

steve: The most common answer to such a question is because they do not have HD (DVB-T2) tuners in.

link to this comment
Dave Lindsay's 5,724 posts GB flag
Friday, 9 November 2012
T
Tim Newton
5:17 PM
Woodbridge

Hi Brian,

Many thanks for your offer of a dump of the data you are using. I would be keen to take you up on that offer if it is still open. Perhaps you could contact me directly on my e-mail address to discuss?

Many thanks,
Tim.

link to this comment
Tim Newton's 5 posts GB flag
Tim's: mapT's Freeview map terrainT's terrain plot wavesT's frequency data T's Freeview Detailed Coverage
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