Christian McArdle wrote:
Incidentally, I already use a feed off the (now broken) aerial for the
digital TV card in my PC, and that seemed to work perfectly OK. Does
that mean a standard aerial should be OK? As in, is digital TV reception
"all or nothing"??


Nah. It's not all or nothing. The bit rate gets worse and you start getting
drop out, particularly in bad weather. If you're going to pay for someone to
be up there, you might as well fit something decent rather than a crappy
contract aerial.

OK, thanks. So is the highly-expensive (IMHO!) digital aerial that this
bloke wants to fit sound like it might be what's required?

If I was to diy I'd be very grateful for pointers as to where to buy a
decent aerial of the correct spec! What about this one?
http://www.tlc-direct.co.uk/Products/MXD19.html Still way less than the
apparent cost from my local riggers...

Thanks
David

My old aerial (not specifically digital) is pointing in the direction of the
Sudbury transmitter and I cannot receive any ITV or Channel 4 channels
except E4+1. anyone know if these channels are being broadcast from Sudbury.
All the channels I do receive 71 in total (44 TV) have good signal strength
and are good quality. Should I buy a new aerial? I using the SONY
receiver.

Martin.

"Lobster" wrote in message
...
Christian McArdle wrote:
Incidentally, I already use a feed off the (now broken) aerial for the
digital TV card in my PC, and that seemed to work perfectly OK. Does
that mean a standard aerial should be OK? As in, is digital TV reception
"all or nothing"??


Nah. It's not all or nothing. The bit rate gets worse and you start
getting
drop out, particularly in bad weather. If you're going to pay for
someone to
be up there, you might as well fit something decent rather than a crappy
contract aerial.

OK, thanks. So is the highly-expensive (IMHO!) digital aerial that this
bloke wants to fit sound like it might be what's required?

If I was to diy I'd be very grateful for pointers as to where to buy a
decent aerial of the correct spec! What about this one?
http://www.tlc-direct.co.uk/Products/MXD19.html Still way less than the
apparent cost from my local riggers...

Thanks
David

On Mon, 7 Nov 2005 18:36:44 UTC, "Martin" wrote:

My old aerial (not specifically digital) is pointing in the direction of the
Sudbury transmitter and I cannot receive any ITV or Channel 4 channels
except E4+1. anyone know if these channels are being broadcast from Sudbury.

Which Sudbury? Anyway, start here...

http://www.dtg.org.uk/retailer/transmitters.html

Lots of stuff about antennas etc. on the same site.

--
The information contained in this post is copyright the
poster, and specifically may not be published in, or used by
Avenue Supplies, http://avenuesupplies.co.uk

Matt Beard wrote:

Lobster wrote:

Need a new TV aerial; I note Screwfix sell different models for 'strong'
and 'weak' signal areas. AFAIK we're in a fairly OK area, but my
question is, is there any disadvantage in fitting the 'weak signal' type
if it might not be necessary? Otherwise it's clearly not worth even
considering paying two quid less for the 'strong' variety?

David


Aerials for weak areas have greater gain, this means that you get more
signal, but you also get more noise.

Not true.

Antenna gain is noiseless. You only get noise when you introduce
amplification using electronics.

I will be happy to be proved wrong though :-)

Dave

Dave wrote:
Aerials for weak areas have greater gain, this means that you get more
signal, but you also get more noise.

Not true.

Antenna gain is noiseless. You only get noise when you introduce
amplification using electronics.

I will be happy to be proved wrong though :-)

Dave

It depends on what you class as "noise". High gain antennae tend to
pick up signals from other sources than the intended transmitter - many
class these signals as noise (they are included in calculations for
SNR)

On Mon, 07 Nov 2005 18:29:46 GMT, Lobster
wrote:

Christian McArdle wrote:
Incidentally, I already use a feed off the (now broken) aerial for the
digital TV card in my PC, and that seemed to work perfectly OK. Does
that mean a standard aerial should be OK? As in, is digital TV reception
"all or nothing"??


Nah. It's not all or nothing. The bit rate gets worse and you start getting
drop out, particularly in bad weather. If you're going to pay for someone to
be up there, you might as well fit something decent rather than a crappy
contract aerial.

OK, thanks. So is the highly-expensive (IMHO!) digital aerial that this
bloke wants to fit sound like it might be what's required?

If I was to diy I'd be very grateful for pointers as to where to buy a
decent aerial of the correct spec! What about this one?
http://www.tlc-direct.co.uk/Products/MXD19.html Still way less than the
apparent cost from my local riggers...

Thanks
David

Your local riggers have to pay for advertising, a van, loads of
insurance, somewhere to store the gear etc. etc. Plus they have enough
experience, often hard-won, to handle problems when they come up
against them. If it was dead easy, people couldn't make a living out
of it. Like a lot of things, really.

BB

--
www.kruse.co.uk/
The buffalo have gone

In message , Big Bill
writes
On Mon, 07 Nov 2005 18:29:46 GMT, Lobster
wrote:

Christian McArdle wrote:
Incidentally, I already use a feed off the (now broken) aerial for the
digital TV card in my PC, and that seemed to work perfectly OK. Does
that mean a standard aerial should be OK? As in, is digital TV reception
"all or nothing"??


Nah. It's not all or nothing. The bit rate gets worse and you start getting
drop out, particularly in bad weather. If you're going to pay for someone to
be up there, you might as well fit something decent rather than a crappy
contract aerial.

OK, thanks. So is the highly-expensive (IMHO!) digital aerial that this
bloke wants to fit sound like it might be what's required?

If I was to diy I'd be very grateful for pointers as to where to buy a
decent aerial of the correct spec! What about this one?
http://www.tlc-direct.co.uk/Products/MXD19.html Still way less than the
apparent cost from my local riggers...

Thanks
David

Your local riggers have to pay for advertising, a van, loads of
insurance, somewhere to store the gear etc. etc. Plus they have enough
experience, often hard-won, to handle problems when they come up
against them. If it was dead easy, people couldn't make a living out
of it.

I dunno, look at IT



--
geoff

Lobster typed:



Today I was quoted 47+vat for a straightforward replacment of the
existing bog-standard 8-element aerial; or about 90+vat if I wanted a
digital-compatible one (and that's definitely just for the aerial, as
all the cable is already new CT100). Wow!

The guy said it would be one like 'next door's - which from my
uneducated viewpoint looks something like this one:
http://www.wrightsaerials.tv/029%202%20hi%20gain%20&%20DAB.html. I
reckon about 1 in 20 aerials in our street are like that; the rest are
like mine. Is this beast really so much more expensive than a common
or garden aerial, and is it necessary?

Top one is an Antiference XG see below for price compered to standard .
http://tinyurl.com/c7f25


-

Big Bill wrote:

Your local riggers have to pay for advertising, a van, loads of
insurance, somewhere to store the gear etc. etc. Plus they have enough
experience, often hard-won, to handle problems when they come up
against them. If it was dead easy, people couldn't make a living out
of it. Like a lot of things, really.

Of course, no complaints with that. I wasn't querying the cost of their
labour/expertise, it was whether the digital aerial which they were
suggesting was (a) justified and (b) genuinely cost about 50 quid more
than the analogue equivalent. From what others have said it sounds like
that's a 'yes' on both fronts.

David

On Tue, 8 Nov 2005 08:39:37 UTC, The Natural Philosopher wrote:

On Mon, 7 Nov 2005 18:36:44 -0000, Martin wrote:

My old aerial (not specifically digital) is pointing in the direction of the
Sudbury transmitter and I cannot receive any ITV or Channel 4 channels
except E4+1. anyone know if these channels are being broadcast from Sudbury.
All the channels I do receive 71 in total (44 TV) have good signal strength
and are good quality. Should I buy a new aerial? I using the SONY
receiver.

I get all MUXES from Sudbury on a sony receiver. 10-12 miles away..

Which Sudbury? London or Suffolk?
--
The information contained in this post is copyright the
poster, and specifically may not be published in, or used by
Avenue Supplies, http://avenuesupplies.co.uk

On Mon, 7 Nov 2005 18:36:44 -0000, Martin wrote:

My old aerial (not specifically digital) is pointing in the direction of the
Sudbury transmitter and I cannot receive any ITV or Channel 4 channels
except E4+1. anyone know if these channels are being broadcast from Sudbury.
All the channels I do receive 71 in total (44 TV) have good signal strength
and are good quality. Should I buy a new aerial? I using the SONY
receiver.

I get all MUXES from Sudbury on a sony receiver. 10-12 miles away..

I use a loft mounted analog spec aerial.

I think a lot depends where you are...its fairly up and down contour wise.

On Tue, 08 Nov 2005 07:45:24 GMT, Lobster wrote:

Big Bill wrote:

Your local riggers have to pay for advertising, a van, loads of
insurance, somewhere to store the gear etc. etc. Plus they have enough
experience, often hard-won, to handle problems when they come up
against them. If it was dead easy, people couldn't make a living out
of it. Like a lot of things, really.

Of course, no complaints with that. I wasn't querying the cost of their
labour/expertise, it was whether the digital aerial which they were
suggesting was (a) justified and (b) genuinely cost about 50 quid more
than the analogue equivalent. From what others have said it sounds like
that's a 'yes' on both fronts.


I bougfht an aerial from a place that specialises in TV installations. The
expensive ones were 18 quid, the less expensive one was 11 quid.

I am using the 11 quid one with toal success.

In a fancy box in a shed the same aerial goes for around 45 quid.

David

On Mon, 7 Nov 2005 21:44:11 +0000 (UTC), Dave wrote:

Matt Beard wrote:

Lobster wrote:

Need a new TV aerial; I note Screwfix sell different models for 'strong'
and 'weak' signal areas. AFAIK we're in a fairly OK area, but my
question is, is there any disadvantage in fitting the 'weak signal' type
if it might not be necessary? Otherwise it's clearly not worth even
considering paying two quid less for the 'strong' variety?

David

Aerials for weak areas have greater gain, this means that you get more
signal, but you also get more noise.

Not true.

Antenna gain is noiseless. You only get noise when you introduce
amplification using electronics.

I will be happy to be proved wrong though :-)

Dave

Well the answer is yes and no.

Any in and noise will be subject to extra boosting, but so what - in band
noise is not somethug yoiu cabdo anything about anyway.

No extra noise will be added of course, other than by the actual resistance
of the antenna and its drop cable...

So depending on how you interepret 'get more noise' the answer can be yes
or no, buit with the addendum that it matters not a sod anyway.

The idea of an antenna is to do two things

- get as much signal into the first amplification stage as possible so that
the input signal is well above the amplification noise floor.

- provide much greater gain for the wanted signal than other unwanted ones,
so as to reduce ghosting and out of band interference.

n very high signal areas and with digital setups there is no point in going
beyind a certain point on the first count =- either you have an adequacy of
signal or you don't. If you don't you get pixellation and/or a loss of
signal altogether.

Likewise with digital the finer nuances of tuning the antenna for rejection
of multipath off fixed objecst (as opposed to aircraft) are uncesseary: As
long as te reflections are about 10-20dB less than the main signal, the
digital decoder is likely to ignore them.

This makes the issue of a digital aerial pretty simple. You simply need to
get a good strong signal and provided its not _totally _being interfered
with it will decode well.

All teh thiungs that are releavnt in an analogue aerial - ghosting, narrow
beam, etc, overoading of te front end etc - are almost completely
irrelevant BELOW A CERTAIN :LEVEL. The digital takes care of all of it.

Increasing signal quality beyind what is required by sticking a ruddy great
array of whatever up a mile high pole is as useful as using red dye on your
CD's to get better sound quailty.

Use of high gain or narrow beam antennae is pretty spurious as is high
quality downlead. I've gt the best downlead there is, and I still get
pickup of sparking contacts in the house thermostats.,.

So don't get carried away with your digital aerial. Either your are one of
the 99% of peple who are withing decent range and you will simply connect
up and get a perfect signal, or you are one of the marginal one percent who
will need to spend money and care on an installation of some complexity.

Of course every rigger in the book will be telling you a load of bull****
and trying to sell you gold plated connectors, ultra expensive drop cables
and the biggest load of pigeon rooster he can find in his trade catalogues,
all at 100% markup, but that doesn't mean you NEED it.

In article , Bob Eager
writes
On Tue, 8 Nov 2005 08:39:37 UTC, The Natural Philosopher wrote:

On Mon, 7 Nov 2005 18:36:44 -0000, Martin wrote:

My old aerial (not specifically digital) is pointing in the direction of the
Sudbury transmitter and I cannot receive any ITV or Channel 4 channels
except E4+1. anyone know if these channels are being broadcast from Sudbury.
All the channels I do receive 71 in total (44 TV) have good signal strength
and are good quality. Should I buy a new aerial? I using the SONY
receiver.

I get all MUXES from Sudbury on a sony receiver. 10-12 miles away..

Which Sudbury? London or Suffolk?

This one!...

http://tx.mb21.co.uk/gallery/sudbury.asp

--
Tony Sayer

Christian McArdle wrote:
snip good advice

15m = you might well be lucky anyway
15-30m = an aerial side booster will help you achieve near enough 100%
30m = you might struggle to get a 100% decent connection (although it
might work a bit)

A quick mental tot up says around 15m. I think there is one permanent
splice.

You could also replace the cable from the aerial through the loft and down
the wall and just convert to the crappy cable for the concealed section that
is too difficult or expensive to replace. If you do this, you must take
great care to make a waterproof splice as the cable will be massively
affected by water ingress.

This would be possible. the run is outside until it comes in under the
suspended floor, so I could easily stick an IP65 box on teh outside of
the house and join the two parts.

Thanks for the comments - I do at least feel like there is some hope
now!

--
Steve F

On Tue, 8 Nov 2005 10:01:09 UTC, tony sayer wrote:

Which Sudbury? London or Suffolk?

This one!...

http://tx.mb21.co.uk/gallery/sudbury.asp

Aha! Yes, I've seen those...when trying to work out why my
mother-in-law's reception was so bad (she lives *in* Sudbury, on the top
of a hill...)

--
The information contained in this post is copyright the
poster, and specifically may not be published in, or used by
Avenue Supplies, http://avenuesupplies.co.uk

"The Natural Philosopher" wrote in message
...
On Mon, 7 Nov 2005 18:36:44 -0000, Martin wrote:

My old aerial (not specifically digital) is pointing in the direction of
the
Sudbury transmitter and I cannot receive any ITV or Channel 4 channels
except E4+1. anyone know if these channels are being broadcast from
Sudbury.
All the channels I do receive 71 in total (44 TV) have good signal
strength
and are good quality. Should I buy a new aerial? I using the SONY
receiver.

I get all MUXES from Sudbury on a sony receiver. 10-12 miles away..

I use a loft mounted analog spec aerial.

I think a lot depends where you are...its fairly up and down contour wise.

I'm about 14 miles away but I have noticed my aerial is about 15 degrees
offset from all the neighbours so maybe I'll try and swing it in the right
direction.

In article , Lobster
writes
Big Bill wrote:

Your local riggers have to pay for advertising, a van, loads of
insurance, somewhere to store the gear etc. etc. Plus they have enough
experience, often hard-won, to handle problems when they come up
against them. If it was dead easy, people couldn't make a living out
of it. Like a lot of things, really.

Of course, no complaints with that. I wasn't querying the cost of their
labour/expertise, it was whether the digital aerial which they were
suggesting was (a) justified and (b) genuinely cost about 50 quid more
than the analogue equivalent. From what others have said it sounds like
that's a 'yes' on both fronts.

David

Try posting over on uk.tech.digital.tv where this argument is known
to rage on a bit;;.

A digital aerial is more expensive than an analogue one because the
public perceives it as such... otherwise their much the same thing..

A bit of marketing bollokx for the aerial rigging trade;=-!!
--
Tony Sayer

In article , says...
snip
Increasing signal quality beyind what is required by sticking a ruddy great
array of whatever up a mile high pole is as useful as using red dye on your
CD's to get better sound quailty.

Don't be silly - you need to freeze them and scribble on them with green
pen :-)

A digital aerial is more expensive than an analogue one because the
public perceives it as such... otherwise their much the same thing..

A bit of marketing bollokx for the aerial rigging trade;=-!!

"Digital" is just code for wideband, which is (a) rarely required for
analogue transmissions that are designed to be in in-band (except maybe
Channel 5) and (b) requires considerable redesign (specifically of Yagi
arrays) to achieve satisfactory results.

Christian.

In article , Christian McArdle
wrote:


"Digital" is just code for wideband, which is (a) rarely required for
analogue transmissions that are designed to be in in-band (except maybe
Channel 5) and (b) requires considerable redesign (specifically of Yagi
arrays) to achieve satisfactory results.

A digital spec aerial is a great deal more than just a "wideband". In fact
an aerial can have been passed as conforming without being wideband. The
differences are manyfold, not the least of which is the prescence of a
balun.

--
AJL Electronics (G6FGO) Ltd : Satellite and TV aerial systems
http://www.classicmicrocars.co.uk : http://www.ajlelectronics.co.uk

On Thu, 10 Nov 2005 08:16:23 +0100, Andy Luckman (AJL Electronics) wrote:

In article , Christian McArdle
wrote:


"Digital" is just code for wideband, which is (a) rarely required for
analogue transmissions that are designed to be in in-band (except maybe
Channel 5) and (b) requires considerable redesign (specifically of Yagi
arrays) to achieve satisfactory results.

A digital spec aerial is a great deal more than just a "wideband". In fact
an aerial can have been passed as conforming without being wideband. The
differences are manyfold, not the least of which is the prescence of a
balun.

ahaha.

I'll get my tinfoil hat on then..

Remind me never to have uou install an aerial..

In article ,
The Natural Philosopher wrote:
On Thu, 10 Nov 2005 08:16:23 +0100, Andy Luckman (AJL Electronics) wrote:

I'll get my tinfoil hat on then..

Seems like that might be favourite. You will have to take it down from your
loft though where it is undoubtedly doing "service" as an aerial.

Remind me never to have uou install an aerial..

a) You couldn't afford us

b) We would refuse to work down to your standards.

Why must you propagate the myth that "cheap" is the same as "good value for
money"? The points I have made are based on scientific fact and established
good practice in RF, not hype of any sort. You will note that the BBC
engineering department and the CAI will offer you the same advice. But then,
you know best of course.

--
AJL Electronics (G6FGO) Ltd : Satellite and TV aerial systems
http://www.classicmicrocars.co.uk : http://www.ajlelectronics.co.uk

Christian McArdle wrote:

"Digital" is just code for wideband, which is (a) rarely required for
analogue transmissions

Unless you are served by Hannington (Hants/Berks)

BBC 1 39 BBC 2 45 ITV 42 C4 66 C5 35, Ironically just DTT from Hannington
only requires Group B (40,41,43,44,46,50)

--
Mark
Please replace invalid and invalid with gmx and net to reply.

On Fri, 11 Nov 2005 08:32:50 +0100, Andy Luckman (AJL Electronics) wrote:


Why must you propagate the myth that "cheap" is the same as "good value for
money"? The points I have made are based on scientific fact and established
good practice in RF, not hype of any sort. You will note that the BBC
engineering department and the CAI will offer you the same advice. But then,
you know best of course.

Indeed I do.

The day a balun turns one pile of aluminium scrap intyo a 'digital aerial'
is the day I send my degree in electronics back..

;-)

The Natural Philosopher wrote:

The day a balun turns one pile of aluminium scrap intyo a 'digital aerial'
is the day I send my degree in electronics back..

No one said it did. But DTT (DVB-T) as currently transmitted in the UK
is somewhat more demanding of receiving antenna performance than
analogue, particularly if you want (a) an aerial that bears some
relation to the assumptions used by the transmitter planners in regard
to gain, directional properties and cross-polar discrimination, and (b)
freedom from impulsive interference.

The term "digital aerial" has come in to use to mean an antenna that
meets a certain set of criteria that will distinguish it from your "pile
of aluminium scrap."

Go read
http://www.dtg.org.uk/publications/b...rk_aerials.pdf.

A balun is necessary, but not sufficient. The main purpose of a balun
is to prevent coupling between common-mode feeder current (which of
course on a coaxial cable will flow on the outer surface of the outer
conductor) and the wanted (differential-mode) signal path. In the DTT
reception context it reduces coupling between impulsive electrical
interference picked up on the outer of the outer of the coax (acting as
a 'long-wire' aerial) and the wanted signal path. It is most important
to use properly screened outlet plates and receiver flyleads, for
exactly the same reason.

HTH
--
Andy

BBC 1 39 BBC 2 45 ITV 42 C4 66 C5 35, Ironically just DTT from
Hannington
only requires Group B (40,41,43,44,46,50)

But will the frequencies change during analogue switch off? I'd still prefer
to install a wideband in case they do.

Christian.

Christian McArdle wrote:

But will the frequencies change during analogue switch off?

Yes, definitely. In most areas the three public-service muxes will move
on to three of the four original analogue channels. The other three
will go elsewhere, TBA. Channels 31-40 and 63-68 will no longer be used
for what is currently called Freeview, but might be used for new TV
services such as HD and/or DVB-H.

I'd still prefer to install a wideband in case they do.

This is a good strategy, although it's a fair bet that in large centres
of population (i.e. areas served by Crystal Palace, Sutton Coldfield and
Winter Hill) everything will remain more or less in the original aerial
group - although that won't necessarily apply to any new services.

--
Andy

In article , Andy Wade
wrote:

But will the frequencies change during analogue switch off?

Yes, definitely. In most areas the three public-service muxes will move
on to three of the four original analogue channels. The other three
will go elsewhere, TBA. Channels 31-40 and 63-68 will no longer be used
for what is currently called Freeview, but might be used for new TV
services such as HD and/or DVB-H.


Now that differs from my understanding that all the digital will be up in
group C/D. That gives the Bliar thieves the whole of groups A and B to sell
off. Surely there is no other reason for the rapid push to a digital
service?


--
AJL

Andy Luckman (AJL Electronics) wrote:

Now that differs from my understanding that all the digital will be up in
group C/D.

Dunno where you got that bizarre idea from. In principle anything
remains possible, but that one, I think, is most unlikely.

That gives the Bliar thieves the whole of groups A and B to sell
off. Surely there is no other reason for the rapid push to a digital
service?

Conspiracy theory runs wild... The proposal to 'release' 14 channels
(only) has been in the public domain for some time now, although
detailed channel plans certainly aren't, and won't be until
international coordination work is much further advanced. There's also
a major radio regulatory conference in progress (RRC04-06) considering
VHF & UHF broadcast allocations in Region 1 and nothing is firm until
after that concludes next year.

As to "rapid push," it's actually quite slow. From The start of DTT
(1998) to the proposed conclusion of switchover (2012) is 14 years.
Now, let me see, UHF/BBC2 started in '64 and the last 405-line TX shut
down in '85 - that's 21 years, so you could say that the digital
change-over is 30% faster - hardly as drastic as "rapid push" would
suggest, perhaps.

--
Andy

On Tue, 15 Nov 2005 08:27:41 +0100, "Andy Luckman (AJL Electronics)"
wrote:

In article , Andy Wade
wrote:

But will the frequencies change during analogue switch off?

Yes, definitely. In most areas the three public-service muxes will move
on to three of the four original analogue channels. The other three
will go elsewhere, TBA. Channels 31-40 and 63-68 will no longer be used
for what is currently called Freeview, but might be used for new TV
services such as HD and/or DVB-H.


Now that differs from my understanding that all the digital will be up in
group C/D. That gives the Bliar thieves the whole of groups A and B to sell
off. Surely there is no other reason for the rapid push to a digital
service?

It was always the original intention to make money aka the 3G sell off
(albeit on a much smaller scale), as it is there are numerous parts of
the existing allocations lying idle due to the demand completely
evaporating. So the sell off is increasingly more likely not going to
happen, particularly when 99% of traffic uses / will use GSM900/1800
or 3G.


--

It was always the original intention to make money aka the 3G sell off
(albeit on a much smaller scale), as it is there are numerous parts of
the existing allocations lying idle due to the demand completely
evaporating. So the sell off is increasingly more likely not going to
happen, particularly when 99% of traffic uses / will use GSM900/1800
or 3G.

Yeah. They should keep the spectrum for more DVB, IMO. Preferably HDTV.

Christian.

Christian McArdle wrote:

Yeah. They should keep the spectrum for more DVB, IMO. Preferably HDTV.

Yep, that's exactly what the broadcasting lobby is, err, lobbying for.

--
Andy