Freeview: Sudbury (Suffolk, England) Full Freeview transmitter
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Full Freeview on the Sudbury (Suffolk, England) transmitter

Google StreetviewGoogle mapBing mapGoogle Earth52.005,0.786 or 52°0'17"N 0°47'8"ECO10 5NG

4G at 800MHz (at800) Freeview reception issues

Tests now show that SOME households that use masthead amplifiers (and some communal aerial systems) AND are in poor signal areas AND that are very close to a 4G phone mast MAY have their Freeview service disturbed: C60: ArqA
See Expecting 4G interference? Tests now show that you have a one in 300 chance.

This transmitter has no current reported problems

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

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The symbol shows the location of the Sudbury (Suffolk, England) transmitter which serves 440,000 homes.

Other maps:Sudbury regionBBC EastAnglia (East micro region)

Is the transmitter output the same in all directions?

Radiation patterns withheld

What do the colours on the map mean?

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

Which Freeview channels does the Sudbury 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.

MuxAerial positionFrequencyHeightModeWatts
PSB1
BBCA
 horizontal max
C44 (658.0MHz)229m64QAM 8K 2/3
24.1Mb/s DVB-T MPEG2		100,000W
Channel icons
1 BBC One East, 2 BBC Two England, 7 BBC Three, 9 BBC Four, 70 CBBC Channel, 71 CBeebies, 80 BBC News, 81 BBC Parliament, 301 BBC Red Button 1, plus 12 others

PSB2
D3+4
 horizontal max
C41 (634.0MHz)229m64QAM 8K 2/3
24.1Mb/s DVB-T MPEG2		100,000W
Channel icons
3 ITV (Anglia (East micro region)), 4 Channel 4 South ads, 5 Channel 5 Part Network ads, 6 ITV 2, 13 Channel 4+1 South ads, 14 More 4, 28 E4, 33 ITV +1 (Anglia east),

PSB3
BBCB
 horizontal max
C47 (682.0MHz)229m256QAM 32KE 2/3
40.2Mb/s DVB-T2 MPEG4		100,000W
Channel icons
101 BBC One HD (England no regional news), 102 BBC Two HD (England), 103 ITV HD (ITV Meridian Southampton), 104 Channel 4 HD South ads, 303 BBC Red Button HD, plus 1 others

COM4
SDN
 horizontal max
C58 (770.0MHz)186m64QAM 8K 2/3
24.1Mb/s DVB-T MPEG2		100,000W
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 21 others

COM5
ArqA
 horizontal max
C60- (785.8MHz)228m64QAM 8K 3/4
27.1Mb/s DVB-T MPEG2		100,000W
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, 302 BBC Red Button 2, plus 9 others

COM6
ArqB
 horizontal max
C56 (754.0MHz)228m64QAM 8K 3/4
27.1Mb/s DVB-T MPEG2		100,000W
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 22 others



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


BBC Look East (East) 0.8m homes 3.2%
from Norwich NR2 1BH, 77km north-northeast
to BBC East region - 27 masts.
70% of BBC East (East) and BBC East (West) is shared output

ITV Anglia News 0.8m homes 3.2%
from NORWICH NR1 3JG, 78km north-northeast
to ITV Anglia (East) region - 26 masts.
All of lunch, weekend and 80% evening news is shared with Anglia (West)

Are there any self-help relays?

Felixstowe WestTransposer1000 homes +1000 or more homes due to expansion of affected area?
WithamTransposer14 km NE Chelmsford.118 homes

How will the Sudbury (Suffolk, England) transmission frequencies change over time?

years1984-971997-981998-20112011-132013-182013-18
aerial groupB EB EEEEW
600C31com7
C35C5C5
C37com8
C39B
C41ITVITVITVD3+4D3+4D3+4
C44BBC2BBC2BBC2BBCABBCABBCA
C47C4C4C4BBCBBBCBBBCB
C48+A
700C49+1
C50+D
C51BBC1BBC1BBC1
C54C
C56ArqBArqBArqB
C58SDNSDNSDN
C60-ArqA-ArqA-ArqA
800C682

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 6th July and 20th July 2011.

  • COM7, COM8 projected for 2013-16. COM7 and COM8 to operate as Sudbury, Tacolneston SFN.

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

Analogue 1-4 250kW
SDN, ARQA, ARQB, com7, com8, BBCA, D3+4, BBCB(-4dB) 100kW
Analogue 5(-7dB) 50kW
Mux 2*(-14.9dB) 8.1kW
Mux B*(-15.2dB) 7.5kW
Mux 1*(-15.5dB) 7kW
Mux A*(-17dB) 5kW
Mux C*(-22.2dB) 1.5kW
Mux D*(-23.6dB) 1.1kW

Which companies have run the Channel 3 services in the Sudbury 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. Sudbury 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.

N
Nick
Wednesday 11 July 2012 7:47PM Aldeburgh
Hi Dave,
You were possibly talking to the other Nick, but here at Hollesley I am scratching my head.
I actually have three boxes on three separate Sudbury aerials. In analogue days, one aerial was much better for C5. Now I find that the main box, my pvr, on that aerial, shows virtually no signal on ch60 and therefore no reception, whilst the other boxes and aerials are now getting the mux on C60. Dover, on a homemade aerial, at upstairs window height only, brings in all channels!
N
Nick A
Thursday 12 July 2012 2:15PM Bures
So, I tried an attenuator which reduced the signal strength but has no effect on the variable quality. I switched everything around so that the TV alone was carrying the signal and the quality is still variable. So the receivers are blameless (I think). The only thing left is trees, but they have been in full leaf since mid-June and the severest problem has only arisen in the last couple of days.
N
Nick
Thursday 12 July 2012 6:08PM Aldeburgh
the two Nicks are floundering, and if the other one has problems slap bang up against the transmitter, what hope is there for this one?
Better try to get Dover to put on Susie Flowerpot and Stuart White I suppose.
N
Nick A
Friday 13 July 2012 3:12PM Bures
So, for no reason, all channels are now fine, excepting ITV 4 which is really struggling. This is a bore as it is carrying the Tour de France. I have eliminated equipment and signal strength as a culprit. But this is proving to be very frustrating.

J
Jason
Saturday 14 July 2012 8:31PM
Just a quick question, I have noticed that COM 7,8,9 have been asigned channels 31,36,37. Could they not have used these channels for COM 4,5,6 and used channels 56,58,60 for COM 7,8,9 in 2015, would that not have helped reception as channels 36 and 37 are in the range of old group B ariels. There is probably a logical explanition that im failing to see lol.
N
Nick
Sunday 15 July 2012 2:01PM
Hey,
I'm recently having a few problems. My service has been perfect until recently when I have started having problems with my hd channels. All sd channels are on 100% quality but the hd bounces up and down from nearly nothing to 75%. Does anyone have any ideas why this would be?
Dave Lindsay
Sunday 15 July 2012 5:40PM
Nick: In response to your question of 5th July, I referred to the COMs only with respect to Dover because I assumed that you may have wished to pick up the PSBs from one of the Anglia transmitters. If not, then perhaps you may find that Dover's PSBs are also intermittent, probably caused by the mist.

Some devices can't receive channels with negative offsets that are in 8k mode (which is the mode used after switchover). C60 is the only one with a negative offset that Sudbury uses.

Do you have reception on C60 now? Referring to your posting of 11th July @ 7:47PM, could it be that your home-made aerial needs turning a little?
Dave Lindsay
Sunday 15 July 2012 5:41PM
Nick A: Not sure what else to suggest, short of calling in an installer.
Dave Lindsay
Sunday 15 July 2012 5:56PM
Jason: The answer probably has more to do with the way in which things work these days. Channels 21 to 37 were ringfenced at switchover to be "sold" to three licencees for them to create their own network.

If there were plans for them to use particular channels at particular transmitters than this would be in effect telling them what transmitters they had to use.

The ringfencing of 31 to 37 is complete nonsense that has resulted in some areas have clashing channels as well as others with out of group channels when they otherwise wouldn't have been.

I agree that from a practical engineering point of view that channels within group should have been allocated where possible, but that isn't the way things are done these days.

A "free market" approach must be taken which means sacrifices. In a free market, providers have choices as to where they serve and consumers have the choice whether to consume. If it means that the latter have to fork out for a new aerial, then so be it.
K
KMJ,Derby
Monday 16 July 2012 6:10PM
Jason: It is possible that the current COM muxes might use the plan for COM 7,8,9, at least in part, if the plan to extend the 4G frequencies down to C49 goes ahead. There are a number of suggestions put forward by Arquiva to facilitate clearance of additional frequencies. This varies from only having the PSB muxes on Freeview (a course already taken by Belgium); allocating the COMs to C31 to C37 with additional use of C48 and C28, or using C22, C25, C28 at all/most the full Freeview transmitters as a SFN, which would allow C31-C37 to be auctioned off for additional Freeview services. The problem with the last plan, apart from needing agreement with other countries who could be affected at times of inversion, is the necessity to re-engineer the PSB muxes at a number of sites. The plans also need DVB-T2 transmission to be adopted in order to put the SFNs in place. At the present time suitable receivers are in the minority but it is suggested that using DVB-T2 might be necessary "sooner, rather than later"
N
Nick
Tuesday 17 July 2012 7:45PM Woodbridge
Dave, thanks for your assistance. What exactly is negative offset?
With certain aerials I can now get c60, but the signal is weak, no comparison with c58.
Dover, however, continues at 100%.
N
Nick
Tuesday 17 July 2012 8:03PM Woodbridge
I notice Sudbury, traditionally group B, now has more muxes in group C than B, and Tacolneston, traditionally group C, now has channels in group B. They do like to make things difficult.
Dave Lindsay
Wednesday 18 July 2012 7:55PM
Nick: Negative offset means that the signal is centred 200kHz lower than the "centre" of the channel. A positive offset is 200kHz above the centre of the channel.

For example, C60 is centred on 786.0MHz, C60- is 785.8MHz and C60+ is 786.2MHz.


In all but a handful of cases, PSBs are on channels within the former four-channel analogue Groups for each transmitter. Where possible, COMs are also in Group, but there are now a number of high power transmitters that have COMs outside of their native Groups.

Sudbury's three PSBs are in Group B and its COMs are in C/D.

Tacolneston's PSBs are Group C/D and its COMs are Group B.
N
Nick
Thursday 19 July 2012 12:17PM Woodbridge
Thanks Dave.
I get from this that C60- is slightly less out of group B aerials than C60.
Does this mean that if they chose, they could put some stations on three frequencies all centred on C60?
I suppose there is some good reason for Tac and Sud not to be able to swap some muxes so as to return to their traditions of groups C and B so that we don't have to buy new aerials.
I am still not certain why you mentioned the minus part of C60. Are you saying it may be harder to receive than if it were not minus?
I am amazed that there is a good signal on C58, but almost zero on C60, particularly on one aerial.
J
Jason
Friday 20 July 2012 8:05PM
Thanks for the replies and making the situation clear in a manner that i can understand, i had also noticed that the com muxs at Sud were in C/D and those at Tac were in B, was going to ask the same question as Nick as to why they could not be swapped over, but i guess that seams to be the way things have gone during the switch over {nothing was ever going to be simple} doing a bit of reasearch i think I have found six main transmitters that are broadcasting coms out of the transmitters orignal group, think there may probably be some repeaters as well, so we are not the only ones to suffer. And thanks to all that post as it makes this a very informative and helpful site.
N
Nick g
Sunday 22 July 2012 2:29PM
Since the power has been turned up on all multiplexes my hd signal is now really poor with regular breakup. Why is this?
Please help!

Any help appreciated
J
jb38
Sunday 22 July 2012 7:31PM
Nick g: This is nearly always caused by the signal received verging on being excessively high, as this situation will affect HD reception even although SD appears to be OK, and although you havent mentioned your location nor anything about your aerial if you are using any type of booster then try by passing it.

Another test to try is by using a set top aerial or a short piece of wire (about 18" min) connected into the aerial socket of your TV / box, but if you come back with your post code or one from nearby (a shop / pub etc) then further advice appropriate to your situation can be given.


Dave Lindsay
Tuesday 24 July 2012 8:30PM
Nick: C60- is still above C59 and C59+ for that matter!

If there is a signal on C60-, then there can't be one on C60 or C59+ or, I believe C59. There could be on C59- though. Each signal has a specific bandwidth; that is the "width" of frequency it uses.

As an example, take Caldbeck. Transmitters that use C30 have a negative offset, so it is always C30-.

Caldbeck uses C22- C23- C24- C25- C26- C27- C28- C29- C30-

So because C30 has a negative offset, then C29 must do so as well, and so on and so forth.

Had there been no C28-, for example, then C27 and below wouldn't have had negative offsets.

The reason for nine channels is because Caldbeck transmits English and Scottish regional variants.
Dave Lindsay
Tuesday 24 July 2012 9:02PM
Nick, Jason: There are many transmitters and only a relatively few channels. Had there only been two transmitters — Sudbury and Tacolneston — then no doubt they would have had all channels within each one's Group.

The main plan was to have PSBs in the same Group as the former four-channel analogue. Crucially this was so as to ensure that existing aerials would work; in some cases replacement aerials would be needed to receive the COMs and in others the COMs would be unavailable.

C61 to C68 which were formerly used for analogue are to be cleared. Some C/D transmitters have given up use of these channels at switchover and others will do so over in the next year or so. These frequencies are being set aside for 4G mobile operators. What it does mean is that there are now less C/D channels available than before.

Also, C31 to C37 have been ringfenced and are not used after switchover. Consequently available Group A channels are now C21 to C30.

Belmont is traditionally Group A. Its PSBs and COM4 are Group A, but the other two COMs are on C53 and C60. Similarly, Sandy Heath is also formerly Group A, with its PSBs being in that Group, but COMs being on C48, C51 and C52. Also consider Waltham which has five muxes in C/D but COM4 on a lowly C29.

These transmitters overlap, so the channels are:

21 Sandy Heath PSB3
22 Belmont PSB1
24 Sandy Heath PSB2
25 Belmont PSB2
27 Sandy Heath PSB1
28 Belmont PSB3
29 Waltham COM4
30 Belmont COM4
42 Tacolneston COM4
45 Tacolneston COM5
48 Sandy Heath COM6
50 Tacolneston COM6
51 Sandy Heath COM4
52 Sandy Heath COM5
53 Belmont COM5
54 Waltham PSB2
55 Tacolneston PSB1
56 Waltham COM5
57 Waltham COM6
58 Waltham PSB3
59 Tacolneston PSB2
60 Belmont COM6
61 Waltham PSB1
62 Tacolneston PSB3

Hopefully you get the idea. Think of the other high power transmitters that overlap these; Sutton Coldfield, Sudbury, Emley Moor.....

Then there are PSB relays within the coverage of each that requires channels within the Group of former analogue ones.
N
Nick
Wednesday 25 July 2012 9:38AM Woodbridge
Dave, thank you for that.
I am currently trying to work out an aerial that will get me ch 60, far and away the most difficult. If you have any idea what channel will be substituted for it and when, you will save me the bother of installing yet another aerial which may or may not work.
K
Kevin Hodges
Wednesday 25 July 2012 11:56AM Chelmsford
Nick, for what it's worth I've a wideband 'X' beam aerial in the loft (feeding the TVs via a 4 way amp) and pick up all the Sudbury mux's loud and clear here in sunny Chelmsford. I assume that with the long term proposals to increase the number of mux's all aerials will need to be wideband
R
RobertB
Wednesday 25 July 2012 12:03PM
Nick I've lived in the Woodbridge area for many years. TV reception has always been a problem in several areas of the town and surrounding area. You will see some aerials pointing towards Sudbury main , some Aldeburgh and others Woodbridge relays. Why not forget Freeview and go for FreeSat? Many more channels good reception. You'd have the expense of a dish and box but should solve reception problems.
N
Nick
Wednesday 25 July 2012 5:57PM Woodbridge
Thanks Kevin and Robert.
Freesat seems to be the answer, but recorder box is about £250, have the dish.
That Sudbury xmitter is so frustrating, all the muxes except channel 60, Arq A.
I am on the coast, Dover gives a full service, but miss the local stuff.
Dave Lindsay
Wednesday 25 July 2012 9:19PM
Nick: What is the make and model of your receiver?

Am I right that you have said a few weeks back that others in your locality also cannot receive C60, but can pick-up C58 and C56 ?
Dave Lindsay
Wednesday 25 July 2012 9:24PM
jb38: Dover uses C59 and Nick says that it comes in strong. Do you think that the difficulty with Sudbury's C60- could be that it is offset towards Dover's C59 ?
K
Kevin Hodges
Thursday 26 July 2012 9:08AM Chelmsford
Nick, do you receive Dover whilst having the aerial positioned towards Sudbury? There would appear to be about 90deg difference in the transmitter directions.
N
Nick
Thursday 26 July 2012 2:13PM Woodbridge
Dave and Kevin,
I have three boxes on three Sudbury aerials. No one box is better than the other and each one works slightly differently, reception-wise, but only because they are on different aerials. If I swap aerials, they are all the same. No aerial gets c60, except occasionally, whilst c58 is usually ok.
I also have an aerial specifically on Dover which I put on the shed to get Dover analogue to play with old tvs when Sudbury ceased analogue. When Dover went digital, I thought I would take it down----but then found it was the only way to get the full digital service!
I think re Sudbury those in authority have much to answer for. When ITV 3 was on 14 kw it was fine, now on a new channel on 100kw it comes and goes.
Having said all that, yesterday I could not even get a picture that would not break up even on c41, from Sudbury, which I put down to the Dutch, who came in with the aerial at 90 degrees to Holland.....Dover...she was fine!
J
jb38
Thursday 26 July 2012 5:20PM
Dave Lindsay: Yes, that aspect could well be a factor and especially if Dover is as strong as is reported by Nick as it could be desensitizing the tuner, although I cant help but feel that this level of reception from Dover (@ 66miles / 185 degrees) could well be short lived when the seasonal / tidal conditions change, or even maybe even before it!

J
jb38
Thursday 26 July 2012 5:23PM
Nick: Having just came on a few minutes ago I noticed your latest posting where you mention that you are using three boxes which if connected (in turn) to the same aerial all work about the same, and its this statement that makes me curious as to what brand model numbers they are? the reason I ask is because about 15 different brand names all use the same chassis and likewise all of these brands although different will all perform about the same as each other, and so I just wanted to confirm that this isn't the case with what you are using, as if they were in the multi-brand range that uses a common chassis then obviously for a any reception tests to have any level of validity then the device being used for the reception test would have to be outside of that group.


N
Nick
Thursday 26 July 2012 6:01PM Woodbridge
Thanks both.
The receiver on Dover is in the shed, aerial on the shed at eaves hight housewise. Tuner is Digital Vision AD BEAV. I have tried it almost daily since Dover went digital, always all channels.
In house, 3 on Sudbury. One a tiny cheapy from Tesco, name not to hand, TVOnics digital tv recorder, and the third Digilogic DSTB1000. All sd only.
N
Nick
Thursday 26 July 2012 6:05PM Woodbridge
And the three in the house, on very rare occasions, used to get the very weak signal that was on c63!
N
Nick
Thursday 26 July 2012 6:23PM Woodbridge
Also Icecrypt T5000
J
jb38
Thursday 26 July 2012 9:34PM
Nick: Thanks for that update on equipment used, and on the basis of the models mentioned I suggest that you use the Icecrypt T5000 for your tests, as the Digilogic DSTB1000 is based on the Goodman's GDB3 (a switch over problem box) and the Tesco device uses an unknown model of early Vestel chassis.

The TVonics is a box made (allegedly!) in the UK but with it being a bit suss as far as exactly where the PCB originates from, as I "suspect" (maybe incorrectly) that it might be from Turkey where Vestel is based, as there is very little technical (service) info published about the box.

However I really do think that you would make things a little easier for yourself if you managed to pick up a Humax box, as all Humax devices are fitted with top class stable & sensitive versatile tuners which are absolutely ideal for carrying out experiments involving reception under difficult conditions such as applicable to your own situation, because if a person does not pick up a signal using a Humax box it can safely be assumed that its because that there isn't one there in the first place, something that cannot be said about every device.
N
Nick
Friday 27 July 2012 9:06AM Woodbridge
Thanks JB,
By chance it is the Icecrypt I usually test with.
Can you explain, please, why in the past I have managed occasionally to pick up weak stations on c63? I ask because all the boxes seem to struggle with receiving a high power mux on c60. Are you saying that some boxes, whilst receiving the majority of mux channels, cannot cope with all?
N
Nick
Friday 27 July 2012 12:45PM Woodbridge
This morning the Icecrypt received c60, sig qual 80%, strength 90.
By lunchtime, lost it, sig qual around 30%.
Hey ho.
Dave Lindsay
Friday 27 July 2012 1:26PM
Nick: I wonder if the problem is Dover's C59 which is drowning out Sudbury's C60-. I wonder if there is any experimentation you could do, e.g. by measuring Dover's C59 from your shed aerial at different times and I wonder if when Sudbury reception is worse, Dover's may appear better.

Perhaps a phased array will help:

www.wrightsaerials.tv link icon http://www.wrightsaerials….pdf

www.wrightsaerials.tv link icon Wright's Aerials

A higher gain aerial has a narrower acceptance angle; i.e. one is traded for the other.

Obviously you will need two identical model aerials, but I don't know what sort of gain you will need on each. An array of two aerials will give a narrower acceptance angle than a single aerial (of the same model).

jb38, can you suggest? Perhaps the fact that the 14kW signals came in quite well might be a clue. Two Log 40s maybe?
Dave Lindsay
Friday 27 July 2012 3:17PM
Nick: Further to the above suggestion, I have calculated that you need to set the two aerials 744mm apart from their centres. This gives a spacing of half a wavelength at 345 degrees (clockwise) at 778.0MHz which is C59.

That is, the distance from the point on one aerial to the same point on the other aerial, measured perpendicular to the the direction they face, should be 744mm. It is NOT the distance between the two aerials (which will obviously be less than this).
J
jb38
Friday 27 July 2012 5:51PM
Dave Lindsay: The answer re: Log 40's is yes, or even DM Logs, although I still have to say that irrespective of what would be nulled out by constructing this type of system, that if the signal that "is" required is being received at totally erratic levels in the first place then I cant see this arrangement making much of a difference, as this type of set up is really intended to be used in an area where signals on the same frequency but received from two sources at reasonably constant levels are clashing with each other, and although there is nothing really wrong with what you suggest I really feel that after a lot of effort it would end up a disappointment for the reasons given.

Of course the other point is that this system requires "absolute" precision as far as alignment is concerned, and this is another thing that cannot be guaranteed where signals are erratic, as they are bound to be suffering from fluctuations in the angle received which would take the precision element away.



J
jb38
Friday 27 July 2012 5:54PM
Nick: Re: your 09.06am query. Yes, that's exactly it, as in some areas where stations have one or more multiplexes operating with negative offsets on their frequencies there is always a number of older boxes that will perform adversely to this type of situation when coupled to receiving an 8k signal even although they may well have performed OK when used on pre-switchover 2k signals, and even although many of these boxes have been software updated to supposedly overcome this problem its a total hit and miss situation as they can still struggle dependant on the level of the signal being received, this showing up much worse when they are on the weaker side and likewise more difficult to capture in the first place.

That said, the Icecrypt is your only device that is removed from the ranges associated with suffering from these type of problems (as well as others) and with that being why I advised using it for reception tests, which of course you have confirmed that you do!

J
jb38
Friday 27 July 2012 5:57PM
Nick: By the way, the reply I have just posted was pre-typed during a lunch break earlier on but for various reasons could not send it.
N
Nick
Friday 27 July 2012 6:16PM Woodbridge
Gentlemen, thank you.
I do not actually want Dover, so I only need one aerial, on Sudbury, provided it works.
Now I will tell you something that will make you think I am barking.
Using the Icecrypt box, with two homemade aerials, this morning, each in turn on the same high pole in the garden the following happened.
Aerial 1 received all muxes pointed at Sudbury.
Aerial 2, which I consider much higher gain, received all but channel 60. I then turned it 90 degrees approx to see if I could get Tac, but left it on the Sudbury muxes, before a retune. I found that I then got ALL Sudbury muxes!
I then put aerial 1 back, pointed the same way, and got nothing, as should have been the case with aerial 2.
For your info, aerial 2 is a tribeam, with the outer two sets of directors designed for group cd and the centre set for group b. The dipole was a compromise between the two, more or less square and based on the old J beam slot aerial Thus each line of directors hits it.
Finally, are you saying that a strong signal, which should not be so coming from Dover on c59 can knock out a Sudbury signal on 60 minus with the aerial pointed at Sudbury?
N
Nick
Friday 27 July 2012 6:34PM Woodbridge
My tribeam has a balun. The design is based on my very successful Dover aerial, except that the Dover one has three identical sets of directors as all channels used are in/near group cd. The dipole on the Sudbury one is only marginally bigger, in other words, it is still skewed for the higher channels at the expense of 41 and 44.
N
Nick
Friday 27 July 2012 6:52PM Woodbridge
Before you ask me if there are any trees in the way, there are, in the neighbour's garden, directly in line with.....Dover.
J
jb38
Friday 27 July 2012 9:14PM
Nick: In reply to your experiments with home made aerials, if No2 aerial received all but Ch60 from Sudbury, then whilst the box was still sitting on Sudbury muxes you turned the aerial around 90 degrees towards Tacolneston and by carrying out that action you then picked up Ch60 thereby making a full compliment of Sudbury channels, then it can only be for one of two reasons.

(1) that Sudbury's signal is being strongly reflected towards you from some large distant object and that is why you are receiving that station when the aerial isn't pointing towards it, or (2) that the directors on the aerial are acting like restrictors and are partially blocking the signal from reaching the active element, "but" with the element of restriction referred to being cleared when the aerial is turned sideways thereby allowing the signal direct access to the active element, the whole point about directors being that they "have" to be precisely aligned "exactly" facing the direction of the signal or they "will" act as partial blockers, this being why I never advocate high gain aerials being used in any situation unless its not too far off line of sight, and also why a Log aerial (any Log but short ones best) coupled with an amplifier of about 12 / 15db or so can receive far more consistent (and reliable) signals over a large piece of metal work.

What I suggest you do though is to leave your No1 aerial set up in operation and do not alter anything, just leaving it running like that to see how long the reception of all muxes holds out for before conditions cause changes to take place.


J
jb38
Saturday 28 July 2012 1:05PM
Nick: Just a little addition, Re: > I then put aerial (1) back, pointed the same way, and got nothing <, "if" by that you are meaning that when you reconnected No1 aerial into the box again and pointed it in the same direction as was done with the No 2 aerial whereby it received all muxes from Sudbury on by doing this you got nothing, then that would suggest that No1 aerial "is" acting correctly, and that the the second possible reason (re: directors) could be responsible for this strange effect occurring on No 2 aerial, unless that is there was a coax braiding connection problem on the No2 aerial.
N
Nick
Sunday 29 July 2012 9:14PM Woodbridge
Thank you gentlemen. I finally bit the bullet, got on the roof and put up the tribeam. It got a good signal on all muxes, facing the right way, 95 sig strength and at least 80 quality, although both wavered a bit.
I have resolved to leave it as it is, despite today c60 pixellating with sig quality down as low as 30 at times, oh dear, but think this is the best I am going to get. c60 does not like me, c58 has no such reservations!
N
Nick
Sunday 29 July 2012 9:23PM Woodbridge
I only have a small problem now for you kindly to resolve. It insists on picking up the ITV 1 mux a second time on c59. I guess it must be Tac. I do not want this as I might find it pixellating because on wrong xmitter, even though it has already logged the Sudbury version.
When I retune the box, I withhold the aerial till I guess I am near c41 to stop it catching the Aldeburgh xmitter. But I cannot withhold the aerial between 58 and 60!
Dave Lindsay
Monday 30 July 2012 11:35AM
Nick: If your box has manual tuning, then the easy answer is to unplug the aerial so as to miss out C59. Then manually add the missing ones, 58, 60 and possibly 56. If it doesn't, then if you have another aerial that picks up all Sudbury's channels — such as that on your shed — then take the box there and tune it in.

I don't quite understand. If aerial 1 works, then why not install it on your roof to provide you with the full complement of channels in your house? If this is so, then it would suggest that it is possible to pick them all up, although as jb38 suggests, it might be worth trying it over a period of time to see if they all hold.
N
Nick
Monday 30 July 2012 12:54PM Woodbridge
Thanks Dave.
I tried yesterday to put in the whole lot manually, having first deleted, but for some reason got all sorts of odd channels on 1,2, 3, and then BBC 1 etc on the wrong channels.
The shed aerial is on Dover.
I am talking about two different locations. I have been doing my tests at Holleley, which is better situated than Aldeburgh where I installed the tribeam.
Aerial one worked at Hollesley, but would have struggled at Aldeburgh. It is difficult to describe. Imagine a group c/d aerial, old fashioned 18, no balun. The dipole, folded, was doctored so that the bottom half inch widened out into group b. Then remove the two directors nearest the dipole and raise them an inch and replace. Then, an inch below the boom, put in a 7 inch director, then a six and a half, so there are two sets of directors initially, then they merge to take up the remaining 14 which are all 6 ins. Crafty eh?
N
Norm De Plume
Thursday 2 August 2012 8:16AM
Oh joy, I thought we were done with the retuning, but it looks like there's another retune on the way - Freeview channel numbers change on September 19th 2012 | ukfree.tv - 10 years of independent, free digital TV advice

Is this going to be the last one for a while or is there going to be a whole new tranche of retuning required (what about 4G for instance?)

At least I learned how to back up the other half's recording schedule on our Humax PVR some time ago as a retune deletes the list and it takes HOURS to put them all back manually. However, there must be a lot of other people who will be getting quite angry now.
N
Nick
Thursday 2 August 2012 6:25PM Woodbridge
Dave or JB,
I think one of you said the projection for channel 60 for me was not good. I do not understand why one channel should have a worse projection than the others from the same transmitter.
J
jb38
Thursday 2 August 2012 11:28PM
Nick: I cant recall ever having said that nor do I see Dave Lindsay having mentioned it either, as although Ch60 was indeed the subject of discussion I certainly don't see the word "projection" as such having been mentioned.

However on the subject of one channel being received at a very low strength compared to an adjacent channel booming in even although the ERP's of both transmitters are the same, this is just one of these things that can happen with multi-element radiator / multi-channel radiation sources even although they are all from the same mast, as no matter how precise the planning might have been RF signals do not by any means always conform to what's expected (or predicted) and can stray quite considerably from it, likewise there is always an element of pot luck involved should they all be received at roughly similar strengths to each other.

The only clue as to whether this situation may, or may not be applying cases where a signal is being received at a significantly lower level than another that's only one or two channels away, is for tests to be carried out at evenly spaced distances from the mast but on exactly the same angle from it, and if at one of these intermediate distances the channel that's weak at a distance is found to be slighter stronger than the one that was higher at the distance, then that points to a non conformity in the vertical radiation angle and which very little can be done about at the receiving end.

I only mention this for information purposes.



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