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Tacolneston + poor DVB-T + poor analogue = DAT75 ???

black_thunder

Standard Member
Been doing some research on and off for a while now, and have also just spent the last 2 hours searching through this site! ;)

I live in north-east Norfolk, and receive from Tacolneston at a distance of 24miles according to Wolfbane. However, both analogue and digital reception are very poor, with some DVB-T receivers refusing to pick up any digi channels. :rolleyes:

However, I have a Hummy PVR9200 and a Toppy PVR - which both receive the full range of Freeview channels. Both are very "blocky" and pixelated, and when trying to watch the Jap F1 GP on Sunday, was unbearable. :rolleyes: :thumbsdow

My preliminary research suggested the Televes DAT75 would be the best option, as I have already tried various "CAI 2" aerials from B&Q and Maplin, and both were worse than my 15 year old contractor aerial. :thumbsdow :eek:

Reading through this forum though, and I get a bad karma for the DAT75. However, as one local aerial installer posted in this site, Tacolneston, whilst currently on the C/D group for analogue and digital, is likey to also use group E when analogue gets switched off. So being as other CAI 2 aerials were rubbish, then that just leaves me with a CAI 1 wideband, which is the DAT75.

The "monster issue" of the DAT75 obviously raises questions, but I already have my current contractor aerial on a 2" dia 4 metre long pole, rawlbolted to the wall of the house (got no chimney, and live in a terrace) with T & K brackets - and the pole itself is fairly "thick walled", and I have never seen any flex in high winds!

So, should I still go for the DAT75, or is there any other advice? :lease:

I've probabaly missed loads of info out, but I trust you good folks will help prod my grey matter in the right direction. :thumbsup:
 
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black_thunder

Standard Member
Can we assume you have a Masthead amplifier fitted?

No. No masthead amp, though if I go for the DAT75, I will also get the MRD and the power supply.

However, I currently have an SLX Gold 4x booster distributor, with F plug connnections (replaced a Maxview one). This takes a "return" from my RF out of my $ky box & PVRs, and then feeds it to two other locations (bedrooms), though I will be adding a third locat.

Virtually all cable is CT100 - the 5-cell air space type, with just one run of slightly older "brown" cable (difficult to change!).

Any other info you require?
 

scribbler101

Established Member
As we know you have a marginal signal, the masthead amp seems the obvious route - and may do the job with the existing ae if it has a suitable response range.

IIUC Your existing downstairs amp is AFTER the first bit of kit. Have you tried it fed direct from the ae and into your freeview tuner?
 

black_thunder

Standard Member
As we know you have a marginal signal, the masthead amp seems the obvious route - and may do the job with the existing ae if it has a suitable response range.

Just had another look at my aerial. It is a group C/D (green bungs) 17 element contractor type - so two questions. :confused:

Firstly, will this still be suitable after the analoge gets turned off and Tacolneston then also use the group E frequencies?

And if it will still be suitable, what type of mast head amp do I need? Does the masthead amp actually need mounting right next to the aerial, or can it be mounted inside the loft?

Sommat else I forgot :suicide: - the mast also has a "C" shaped FM aerial, about 1 metre below the UHF aerial - would this make any difference?

IIUC Your existing downstairs amp is AFTER the first bit of kit. Have you tried it fed direct from the ae and into your freeview tuner?

Hmmmmm . . . . had another look at my cabling. :oops: The aerial feeds first into a "Labgear" booster amp, then into the Freeview boxes. The the RF cabling goes through the $ky box, upto the SLX 4-way dist amp in the loft. Is this good, bad or indifferent? :blush:
 

scribbler101

Established Member
Freeview on --- TV transmitter | ukfree.tv - independent digital television and switchover advice, since 2002

Freeview reception - all about aerials | ukfree.tv - independent digital television and switchover advice, since 2002

See links re frequencies and aerials. Looks like you will as you say need a E or a W - but don't forget the signal will be VASTLY stronger, so you may well get away with the "wrong" group. Or indeed with a "Sketchley Loop".

FM ae should not be a problem.

I know little of masthead amps, but think that whilst closer the better, in the loft may well do fine. I also don't know if your present amp installed in the loft might be enough. I think masthead amps tend to be (auto)/adjustable for overload outputs.

Your present setup seems to be exactly what I was suggesting!
 

black_thunder

Standard Member
Thanks for the links :smashin:


The first was a little truncated, so I corrected it. ;)

See links re frequencies and aerials. Looks like you will as you say need a E or a W - but don't forget the signal will be VASTLY stronger, so you may well get away with the "wrong" group.

Looking at that freq table, a group E isn't that much different to a proper wideband!

However, as my current set-up isnt really up to the job for both digi and analogue (with analogue teletext pretty useless), and the fact that the C/D will probably become obsolete - because can anyone be sure that the increased power will actually compensate for the "off group" frequencies - is there any real benefit (or hope) of flogging my existing dead horse of an aerial? And just how much stronger will the signal become?

Or indeed with a "Sketchley Loop".

What is one of them? :confused:

FM ae should not be a problem.

OK, thanks. Are there any guidelines for specific minimum separations?

I know little of masthead amps, but think that whilst closer the better, in the loft may well do fine. I also don't know if your present amp installed in the loft might be enough. I think masthead amps tend to be (auto)/adjustable for overload outputs.

OK, looks like some more googling for me then, thanks. :)

Your present setup seems to be exactly what I was suggesting!

OK, cool! :thumbsup:

One other thing I have noticed is that my CT100 cable uses the "silver paper", whereas the better spec'd cables use copper wrap - would this make any difference?
 

scribbler101

Established Member
Phwaay - lotsa stuff

- Whilst I have no problem with you correcting my link, how did you get access to do so? Are you a moderator? Or a hacker?

- If you are not getting teletext that's telling you how good your "digital" reception is. In fact there is a teletext page that assesses your chance of getting digital - someone may know its number?

- NO-ONE can tell you if your present ae will do the job post switchover. But the power increase is 10-50 TIMES, so there's a good chance.

- A "Sketchley Loop Antenna" is a reshaped wire coat hanger.

- FM Ae spacing - dunno, but think a metre will do.

- I am no cable expert - there is a link in FAQs - I think the silver foil wrapped generally has a copper sheath as well. Obviously if your signal is marginal it matters more to keep out interference. But HiFi people fall for anything about wiring so I have doubts too!
 

LV426

Administrator
Staff member
Whilst I have no problem with you correcting my link, how did you get access to do so? Are you a moderator? Or a hacker?
He didn't. It's edited ONLY is the quote of your post in his own post.
If you are not getting teletext that's telling you how good your "digital" reception is. In fact there is a teletext page that assesses your chance of getting digital - someone may know its number?
Limited value, really. Teletext comes on the back of whichever analogue channel you are watching. So it only really signifies how good (or bad) analogue reception of the relevant channel is.

If the channel (aerial) grouping is different at your transmitter for analogue and digital (typically, where a wideband aerial is needed for reception of both; this is the case for most transmitters) then good reception of the clock crusher text page only signifies that your current aerial is good for whichever group the analogue transmissions are in and gives no indication of reception of the digital group.

In a worst case, a local repeater station may well offer perfect reception of analogue and associated text pages, yet no transmission of digital at all.
 

black_thunder

Standard Member
Phwaay - lotsa stuff

Whoops, sorry.:blush: But I'd much rather ask questions now, rather than look stupid later . . . . ;)

- Whilst I have no problem with you correcting my link, how did you get access to do so? Are you a moderator? Or a hacker?

Oh, forgive me, I think there is a slight misunderstanding. I did not correct the link in your post - but what I did do is quote your link in my subsequent reply, and correct that. Sorry if I've caused any confusion, but I can assure you that I am not a moderator, and the only hacking I am actually capable of is when I prune my rose bushes in the garden! :eek:

- If you are not getting teletext that's telling you how good your "digital" reception is. In fact there is a teletext page that assesses your chance of getting digital - someone may know its number?

Actually, my digital text doesn't actually seem too bad (though it is slow to load, and slow transitions between pages - so it could be poor - I dunno how to test it). It is the old skool analogue text which is poor, particularly on ITV and Ch4. Text on analogue Five is a non-starter, because I can barely receive Five without some serious interferance (if that is the best way to describe it) to both sound and vision.

I am aware of the text test pages for the analogue teletext, but if there was one for the digital teletext, then that info would be much appreciated.

- NO-ONE can tell you if your present ae will do the job post switchover. But the power increase is 10-50 TIMES, so there's a good chance.

Ah - OK, thanks. So if I understand correctly, these power increases are just "forecasts" or projected figures?

- A "Sketchley Loop Antenna" is a reshaped wire coat hanger.

LOL - as in dry cleaners! Any links? :lease:

- FM Ae spacing - dunno, but think a metre will do.

Thanks. Mine looks like about 0.8m separation, so I'll tweak that the next time the ladders come out.

- I am no cable expert - there is a link in FAQs - I think the silver foil wrapped generally has a copper sheath as well. Obviously if your signal is marginal it matters more to keep out interference. But HiFi people fall for anything about wiring so I have doubts too!

Thankfully, I'm not a HiFi "enthusiast", and can generally steer clear of marketing hype. ;)

I found this link - Co-ax cable quality - how much does it matter? - and I have one run of the brown (they refer to as type D) low loss, though it is in excellent condition. The rest are all type C, again all in excelent condition. I think I may have to bite the bullet, and get some of the foam dialectric with copper tape - especially for the downlinks.

Thanks again for all you help and advice, very much appreciated. :beer::beer::beer::beer:
 

radioredcat

Established Member
I have some relatives in dereham about 15 miles from tacloneston and their reception is not brilliant but they have sky so they are not bothered about it.
As for a group c/d aerial after switchover CH 42,45 will probibly work ok (i'llprobibly get struck by lightning cos iv'e said that) but i have a 10 element group c/d for winter hill and i can recieve winter hill B CH 40/43 no problem.
As coax what you need is good quality double screened satellite cable from a repituble company i have recently bought a 100m drum from CPC (preston) don't buy it off ebay.
28 years ago i put a (wolsey colour king) which is a grid aerial on my coal shed 6 ft high for the wrekin which is 58 milles away,And i will point out i live high up on a hill.
The coax is the same age and reception is good on analogue/digital i did recently replace the colour king with my traix 92 element group K aerial and guess what the signal strengh with the thomson box was no different.

http://www.avforums.com/forums/freeview/841370-odd-signal-problem-wrekin-transmitter.html


The problem with norfolk is it relativly flat the transmiiter doesn't have the height that other transmitters like winter hill has and thats why there are so many problems with tacolneston it's been well documented over the years.
I don't you need to spend vast amount of on (digital/freeview aerials) as they call them becuase theres no such thing.
This is a good site to look at and learn a few things.

A.T.V (Aerials And Television) Home Page


andy
 

black_thunder

Standard Member
Teletext comes on the back of whichever analogue channel you are watching. So it only really signifies how good (or bad) analogue reception of the relevant channel is.

But that is just one of the issues. My analogue reception - for teletext and the actual pictures is quite poor, with Five being unwatchable. Ch4 is quite bad, sometimes watchable without too much "snow" and othertimes virtually unwatchable at all. BBC1 & 2 and ITV also suffer with snowy picture, though this seems to be dependent on weather conditions - sometimes perfectly reasonable for analogue, other times moderately snowy.

Digital reception on my primary Humax and Topfield PVRs (daisy chained) sometimes appears to be perfect, othertimes, very pixelated, and occasionally picture and sound freezing. Simliar scenarios with digi text - with the Topfield crashing (though I'm not sure if that is an issue with the actual Toppy). Signal meters in both for BBC1 generally indicate 100% strenth, and about 55-60% quality - though the Toppy seems to be a bit more "finite" with its readings compared to the Hummy.

For my bedrooms, receiving piped outputs via an SLX Gold f-plug distributor amp, the analogue signal doesn't appear to suffer any degridation (though this can be difficult to truely determine, when you have a 42" plasma on the living room wall, and a somewhat weedy 14" CRT in the bedroom). Digital in the bedrooms is noticeably poorer than downstairs - tested with 5 different freeview boxes.

If the channel (aerial) grouping is different at your transmitter for analogue and digital (typically, where a wideband aerial is needed for reception of both; this is the case for most transmitters) then good reception of the clock crusher text page only signifies that your current aerial is good for whichever group the analogue transmissions are in and gives no indication of reception of the digital group.

According to Wolfbane, both digi and analogue sigs share the same C/D grouping - therefore my current aerial should be suitable (green bungs). However, a local professional installer who posted in another thread on this forum stated that when the analogue gets turned off, then group E, as well as the current C/D will be used - hence the requirement for a w/b aerial for upgrades or new work - which is why I am tempted by the DAT75. I have tried variety of other CAI2 w/b aerials from B&Q and Maplins, and none gave any improvement over my current "contractor" aerial - hence my reasoning for a CAI cat1 aerial.

BTW, what is the "clock crusher" :confused:

In a worst case, a local repeater station may well offer perfect reception of analogue and associated text pages, yet no transmission of digital at all.

Hmmm . . . I am aware of a very low output one in Norwich, and this is roughly the same compass bearing as Tacolneston - but I thought that the Norwich "beam" (if that is the correct term) is specifically angled to only cover Norwich, and is nowhere near strong enough for me.

Also, looking on the Sitefinder website, there are no GSM or TETRA transmitters nearby (they are about 3/4 mile away, at right angles to Tacolneston).
 

Dreamxtreme

Banned
If your on the North norfolk coast tucked behind those hills that go along the land you might do well to turn your aerial towards Belmont (if you dont mind BBC Lincs news :D ) but i know a few people in Wells and over that way who just dont get Talcolneston at all :thumbsdow but with nothing but water in the way it should fly straight across , they do need a relay up that way i must admit :cool: apart from that there are some extremely good aerials out there which people from East Peterbough use to get TV from TN
 

scribbler101

Established Member
Very flat Norfolk. But that is not a problem in a potential wife so long as she does not make it flatter.

"Clock Crusher" I think refers to the page which allegedly predicts digital signal reception, which consists of alternating black/white blobs - presumably alternating with some incomning time signal, so showing how often it is missed.

Re VHF Ae separation; my "1m" was but a guess. 0.8m I suspect is fine. But you could dismount it entirely to see if it helps?

Your current signal is clearly marginal. Where with analogue that makes a poor pic, with digital you are flipping between usable and unusable - with quick flipping showing as pixellation - as propagation conditions vary, or your ae moves in the wind, or interference signals go on/off.

The future signal strengths are planned. Yours should double.
Better Freeview reception after switchover | ukfree.tv - independent digital television and switchover advice, since 2002
Then I daresay they will embark on improvements to fill in gaps and weak areas.

Incidentally, I THINK that all teletext is digital - even on analogue signals where it uses spare lines.
 

radioredcat

Established Member
The clock cracker is used to check the integrity of the teletext decoder and signal if the signal was ok but the page had errors then there was a problem with the decoder,But that was back in the steam days when they used discete components today they are made up on a couple of chips.



andy
 
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black_thunder

Standard Member
If your on the North norfolk coast tucked behind those hills that go along the land

I'm not actually in "North Norfolk", but am closer to Yarmouth (hence the North East Norfolk ;)), so I don't have the same probs which Cromer, Sherringham and the likes have.

I just have Norwich nigh-on directly in the line of site of Tac. And according to the Megalith website, I seem to have some height obstructions very nearby. About 10 or so years ago (well, it was before all this digital terrestrial palava), I upgraded my previous 20y/o small contractor ae to a much longer contractor ea, and at the same time, raised it from eaves level by about another 3 metres (along with fresh brown cable) - and this did give some improvements to the then analogue signal on a 21"crt, and also much reduced road interferrance.

you might do well to turn your aerial towards Belmont (if you dont mind BBC Lincs news :D )

:thumbsdow I'd rather not. How would I cope without Wendy Hurrell and Julie Reinger? ;) :devil:

there are some extremely good aerials out there which people from East Peterbough use to get TV from TN

Do you know what type of aerials they might be using?
 

IWANTBLUE

Established Member
:thumbsdow I'd rather not. How would I cope without Wendy Hurrell and Julie Reinger? ;) :devil:

Sorry for the thread 'reserection' but this raised a chuckle.... whenever the missus is washing up after tea my son is instructed to give the call "Juuulies on!!!! so that she can come back in to see the weather rofl...

didn't help me with sudden bbc mux signal loss from Tc but made me titter ;)
 

LITTLEHELPER

Standard Member
Hi ive had exactlp the same problem i live in Great Yarmouth and well i haven't got the best arial (its an amplified portable) but i use to get full signal on everything now i struggle to get Channel 4 basically anything on UHF 53 and 64 so i think Tacolneston has lowered is amplitude maybe?
 

mike7

Distinguished Member
Things will improve from Tacolneston in the build-up to switchover. The present mast is being pensioned off and a new, taller, one being built alongside. Of course when the work is complete and switchover comes the output will be considerably greater. Hopefully this will improve a lot of reception problems,particularly on the North Norfolk coast. I'm not sure if work has started. In the end we will all be able to see Julie much more reliably. If you had been at the recent Norfolk Show you would have seen quite a lot of her.

BTW Norfolk isn't totally flat ! There is an area in central Norwich which is only 20 miles from Tacolneston where people cannot get a decent picture analogue or digital. A small transmitter fills this gap, but I believe it has a limited number of digital channels.
 
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whatsupdoc

Established Member
I have a preference for Anglia, not only because of Julie and Wendy, but because they give much better news coverage of my area (SE Essex) than the London stations.

Don't do very well signal-wise though, and I'm not sure if I'm on Tacolneston or Sudbury. I thought it was Sudbury but if I press ? on text it comes up TAC.
 

mike7

Distinguished Member
I have a preference for Anglia, not only because of Julie and Wendy, but because they give much better news coverage of my area (SE Essex) than the London stations.

Don't do very well signal-wise though, and I'm not sure if I'm on Tacolneston or Sudbury. I thought it was Sudbury but if I press ? on text it comes up TAC.

Sudbury is a 'slave' of Tacolneston and is, as far as I know, not identified as Sudbury. You would need to check the frequencies being used to be sure which transmitter you are tuned to.
 

black_thunder

Standard Member
OK, some updates. ;)

I've now upgraded all the existing rather cheap :thumbsdow black CT100 (with aluminium foil screening) with some considerably superior looking Webro WF100 (CAI approved, with copper foil screening). I've still got one length of non CAI approved 75ohm brown cable burried in the wall. :rolleyes: No real improvement. :confused: Will probably have to bite the bullet and change this brown stuff. :facepalm:


Masthead amplifier
Following recommendations from others, :smashin: I've recently bought a masthead amp. It's a 'Wolsey WFAV 25' 25db variable gain jobbie. But it doesn't have any instructions! Where is the best (or permittable) locations to mount the the actual amplifier and the power supply? :rolleyes: Is it possible to mount the amplifier on the wall under the soffit (approx 5 metres down from the aerial), or does it have to be as close to the actual aerial as possible (at the top of a 4 metre mast)?

I plan mounting the power supply in the attic - I trust this is OK?


Thanks for all your help - a great forum!:thumbsup: :beer::beer::beer:
 

morgan_man

Novice Member
Hello Black_Thunder
I'm in the same situation as you. Marginal Freeview reception living between North Walsham and Stalham. Wolfblane reports a hill (mountain?) in Tunstead blocking my line of site to Tacolneston.
Was going along the big mast route - two scaffold poles and a DAT75 on top, when I thought of upgrading the co-ax first. Used the black copper foil satelite cable all the way to my SLX Gold 6x booster distributor and removed my masthead amp! It vastly improved my reception. I'm now replacing all the internal brown co-ax with the satelite cable. I bought a big drum.
I do have a good Triax aerial and a Sony Freeview boxes Not all Freeview boxes are equal and the Sony is the best I've found. I am wondering what to do in November next year for HD content.
PM me if you are near and would like to see what I've done. Maybe could loan you a Sony box to try?
Chris
 

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