What think you of the LIDL digital rabbit ears ?

zod

http://www.lidl.ie/cps/rde/xchg/lidl_ie/hs.xsl/index_9860.htm

on sale this Monday for €12.

Would this do for saorview ok ?

watty

It's no better than a €2 model.

The majority of people need a roof aerial. An indoor aerial only works properly if a window faces the transmitter and you can see it.

The shiny rods are for VHF. Only the loop is used for DTT.
One of the indoor aerials bottom of page here http://www.techtir.ie/radio-tv/uhf-aerials is FAR better, from €6

zod

watty wrote: »

One of the indoor aerials bottom of page here http://www.techtir.ie/radio-tv/uhf-aerials is FAR better, from €6

Where can you buy in Ireland .. have you link ?

Badgermonkey

watty wrote: »

The majority of people need a roof aerial. An indoor aerial only works properly if a window faces the transmitter and you can see it.

I'm 19km from transmitter and €2 rabbits ears work in bedroom facing it.

Amplified Argos indoor aerial works in my front room facing away from transmitter, though only with it set to maximum amplification.

watty

But without professional test gear you don't know what the safety margin is. 19km is meaningless without terrain, layout of house, mast height and power. I'm nearly 14km and a indoor aerial only just works in kitchen (seems fine but there is no safety margin for a drop in signal or increase in interference). An indoor aerial doesn't work anywhere else. We have a small outdoor yagi on Gable end, low enough to reach with step ladder. It feeds a distribution amp for most of the rooms. The transmitter could go to 1/10th power and it would be fine. It's only a 10 element Yagi.

Also indoor aerials are more prone to interference.

If you have no roof aerial and it works, fine. But they are NEVER to be recommended.

Even an attic aerial can be 100 times better.

A distribution amp to feed up to 4 Tvs is inexpensive.

watty

zod wrote: »

Where can you buy in Ireland .. have you link ?

Get a proper aerial on roof!

Those indoor aerials are widely available from €6 to €14. They are FAR better than Lidl aerial, Tesco or Argos models. But I don't recommend ANY indoor aerial. For 95% of people they are a waste.

lucernarian

They're not widely available Watty at least not by my experience of looking around the considerable number of €2 type shops in Dublin city centre or some of the electrical retailers.

Many people unfortunately will not have the money, courage or DIY knowledge to erect their own rooftop aerial. We can all aspire for that but sometimes our advice needs to cut the cloth that we've beeen offered;)

Also, a distribution amp that's not going to cause more harm than good with poor noise values will end up costing about €25 or more. It then usually needs a power socket in the attic and very often that's not available. Which then leads to more work for the poor DIYer and a possibly dangerous electrical wiring situation if they don't know what they're doing with mains electricity.

Using a masthead amp, a power pass-through splitter and a PSU somewhere downstairs will be safer, offer more flexibility and usually masthead amps have better noise values for about €30. And trying out a passive splitter will cost less than €10 and the amp/PSU can be added if that doesn't work.

winston_1

To_be_confirmed wrote: »

Many people unfortunately will not have the money, courage or DIY knowledge to erect their own rooftop aerial.

Strange, they've got the money to buy expensive TV equipment but not to pay for a decent aerial which is perhaps 15% of the cost of the TV.

It's not that they don't have it, it's that they don't want to spend it.

lucernarian

That's a fair point as we are talking about Saorview reception here and that requires having a set top box or a new TV for the most part. But many students could just have a USB DTT tuner that would cost as much as that indoor aerial from Aldi, assuming that many students would also have a new cheapie laptop for college.

In any case, no matter how much money people have, most of us will not spend €100 or even €40 if you do it yourself in an attic or on a pole shared with an existing satellite dish if there is the likelihood of a much cheaper alternative that will give the same results. Of course, attitudes change when walking into a room can result in no signal or glitches but then the attitude is that they only lost €2 or indeed €12 in the hope of saving €90 in getting a proper job done.

Badgermonkey

winston_1 wrote: »

Strange, they've got the money to buy expensive TV equipment but not to pay for a decent aerial which is perhaps 15% of the cost of the TV.

It's not that they don't have it, it's that they don't want to spend it.

That's assuming they install it themselves, which most folks will not and it's simply not just finance which determines that decision.

As I don't have the equipment or the training to work at heights, I'm going to install a yagi in the attic.

As a stop gap measure, an indoor aerial has proved most effective for Saorview which really surprised me, as it has been consistently stated that they would only work in very close proximity to a transmitter.

hdowney

watty wrote: »

It's no better than a €2 model.

The majority of people need a roof aerial. An indoor aerial only works properly if a window faces the transmitter and you can see it.

The shiny rods are for VHF. Only the loop is used for DTT.
One of the indoor aerials bottom of page here http://www.techtir.ie/radio-tv/uhf-aerials is FAR better, from €6

this bit? where exactly is the transmitter so i know in relation to my house. would like to get a roof arial, but not sure as to who i could get to put it up, so might start with a cheapy indoor and see do i get any luck.

lucernarian

http://coverage.rtenl.ie/index.php

hdowney

thank you

v10

watty wrote: »

Get a proper aerial on roof!

Those indoor aerials are widely available from €6 to €14. They are FAR better than Lidl aerial, Tesco or Argos models. But I don't recommend ANY indoor aerial. For 95% of people they are a waste.

I'm glad I ignored this advise.

The lidl aerial got me all the saorview channels in perfect quality for €12. Guess I'm in the 5% then. As for getting the same thing for €6 I had no luck.

NewHillel

watty wrote: »

The majority of people need a roof aerial. An indoor aerial only works properly if a window faces the transmitter and you can see it.

Rubbish.

watty wrote: »

It's no better than a €2 model.

The majority of people need a roof aerial. An indoor aerial only works properly if a window faces the transmitter and you can see it.

The shiny rods are for VHF. Only the loop is used for DTT.
One of the indoor aerials bottom of page here http://www.techtir.ie/radio-tv/uhf-aerials is FAR better, from €6

Have you the technical specification for the Silvercrest unit that would allow you make this judgement? I certainly wouldn't make it without seeing the spec, or else carrying out a basic lab test to compare each of them! An amplified indoor antenna can give a marked improvement in reception, or allow reception where a passive indoor aerial, i.e. one without an amplfier doesn't. Without access to a detailed technical specification its a case of "suck it and see".

For the technically minded...
The amplifier built into an amplified antenna can be effective on two grounds:
1. The noise figure of the amplifier can be better than that of the first stage of the TV receiver.
2. It can provide a better impedance match, accross a range of frequencies, and hence reduced loss.
However, I do agree...
No amplifier can make an indoor aerial as good as an outdoor one, with or without an amplifier.
No amplifier can magic a signal that isn't there, or is too weak, so in many areas an external aerial is a must.

lawhec

Watty's advice on this is sound enough. It is not so much the case that indoor aerials can't work unless you can visually see the transmitter mast, but rather that indoor aerials are a compromise and placed in places which are not ideal for good steady reception.

For many years now in the UK, reputable aerial installers now use double-shielded coax (e.g. WF100) for terrestrial installations because of the need to prevent the likes of ignition interference upsetting DTT reception. Indoor aerials not only are receiving a weaker signal than one on a rooftop, but they are also much closer to sources of interference like light switches, thermostats, GSM mobiles, switch-mode power supplies etc. which for analogue may only cause minor annoyances but on digital can seriously disrupt reception - even something as switching on or off a light in the same room as the TV can cause the picture to freeze for several seconds with a loss of sound.

Another problem is constructive/destructive multipath due to reflections from walls and other objects in the house and outside. One thing I've seen with indoor UHF aerials is that it can be tricky even in good signal areas to find one spot where all signals are at their best, because the different frequencies that are broadcast reaching the aerial may come from several paths in different phases. Ghosting doesn't affect DVB-T except in very poor conditions, but if the signals come to the aerial where the sum is significantly out of phase, then reception strength is reduced while on another frequency in the same place it could be very good. As Saorview is currently only using one multiplex it can be easy to simply aim for the best reception for this one frequency, but once the second multiplex is fully up and running with the chance of more in the future, what works in one spot for the current multiplex may not work for others in the future - and you don't necessarily get just a worse picture as with analogue, you may end up with no picture. Having to adjust the aerial each time changing channels can become a pain.

I remember a test Ofcom did a few years ago measuring indoor aerial use for DTT, and the conclusion was that amplified indoor aerials offered no real improvement over unamplified. Another problem with the amplifier in most cases is that their amplification values are over the top. It looks good for customers to see a "gain of 44db", but GIGO. The only thing the amplifier can achieve is to overcome tuner noise but most tuners these days (especially those designed for DVB-T) are much less noisy compared to say the early 90's.

There's a good guide here about trying to make the best of indoor reception of DTT and its general theme is good - if you're a student, or live in rented accommodation where the landlord doesn't allow you to erect an outdoor aerial, you can try and make the best of it. But if you can get one erected on a roof top by a professional, do so. There's no point spending say €700-1000 on a new TV if the signal you're feeding it is hopeless, best to budget for another €100-150 for someone to do it properly.

And if you haven't got a head for heights or no experience, don't do it - at least not without the right gear and precautions. We don't need more Rod Hulls...

lucernarian

It's more than just people with €700 TVs who are trying to pick up Saorview remember... USB DTT tuners can be bought off the net for less than €15 including delivery and can use laptops or computers people had saved up for already.

Also, my own observations with DTT on any sort of aerial is that reception is quite consistent between muxes from the same site, in comparison to analogue for example. I found this from looking at the MPEG2 DTT tests in Dublin where RTE1 analogue would sometimes look much better than RTE2 or vice versa. Hard to get both to work with just rabbits ears if Kippure wasn't available. But the 4 multiplexes usually came in together. That's quite empirical but what is certain is that if one positions any aerial and gets a strong signal then a small level of reflected signal will be presented as noise or else attenuate the signal directly depending on reflections and carriers etc. This will still leave a perfectly good picture even if C/N ratio has been reduced.

It's the variable reflections that really matter as one can't adjust an aerial as a person is walking through a room, or from moving branches in front of the aerial on a windy day.

As for the typical indoor aerials being sold these days... Many of the larger towns and cities have exceptionally good Saorview coverage in comparison to analogue. If there is a Saorview site right beside the large town or city in question then most places will have a window or other where an indoor aerial would work. The 5 biggest cities and the likes of Clonmel, Longford, Sligo, Tralee, Wexford and various other spots. But the important bit is the window that works. Not much good if it's the bathroom window;)

Indoor aerials are only good while they're near the TV to use. Otherwise you'd need to stick it in the attic and then putting a proper aerial in the attic or indeed outside/in a shed makes more sense.

NewHillel

lawhec wrote: »

Watty's advice on this is sound enough. It is not so much the case that indoor aerials can't work unless you can visually see the transmitter mast, but rather that indoor aerials are a compromise and placed in places which are not ideal for good steady reception.

So, it was rubbish. In fact, if you're too near the mast your reception could be worse as, depending on the TX Aerial configuration, you'll be in shadow.

lawhec wrote: »

Indoor aerials not only are receiving a weaker signal than one on a rooftop, but they are also much closer to sources of interference like light switches, thermostats, GSM mobiles, switch-mode power supplies etc. which for analogue may only cause minor annoyances but on digital can seriously disrupt reception - even something as switching on or off a light in the same room as the TV can cause the picture to freeze for several seconds with a loss of sound.

Agreed.

lawhec wrote: »

Another problem is constructive/destructive multipath due to reflections from walls and other objects in the house and outside. One thing I've seen with indoor UHF aerials is that it can be tricky even in good signal areas to find one spot where all signals are at their best, because the different frequencies that are broadcast reaching the aerial may come from several paths in different phases. Ghosting doesn't affect DVB-T except in very poor conditions, but if the signals come to the aerial where the sum is significantly out of phase, then reception strength is reduced while on another frequency in the same place it could be very good. As Saorview is currently only using one multiplex it can be easy to simply aim for the best reception for this one frequency, but once the second multiplex is fully up and running with the chance of more in the future, what works in one spot for the current multiplex may not work for others in the future - and you don't necessarily get just a worse picture as with analogue, you may end up with no picture. Having to adjust the aerial each time changing channels can become a pain.

It is extremely unlikely that this will be an issue as the digital coding technique being used for the Irish DTT is far more resilient than analogue.

lawhec wrote: »

I remember a test Ofcom did a few years ago measuring indoor aerial use for DTT, and the conclusion was that amplified indoor aerials offered no real improvement over unamplified.

Any such conclusion would only be relevant to the particular amplified indoor aerial tested. This technology has improved greatly in recent years and the cost has fallen dramatically. (Can you remember any details, as I wouldn't mind following this up?)

lawhec wrote: »

Another problem with the amplifier in most cases is that their amplification values are over the top. It looks good for customers to see a "gain of 44db", but GIGO.

Agreed, but most have a variable gain control that can be turned down, so not a problem in practice.

lawhec wrote: »

The only thing the amplifier can achieve is to overcome tuner noise...

You are incorrect. They also provide active equalization - hence providing a better impedance match, across a range of frequencies, leading to lower loss.

lawhec wrote: »

There's a good guide here about trying to make the best of indoor reception of DTT and its general theme is good - if you're a student, or live in rented accommodation where the landlord doesn't allow you to erect an outdoor aerial, you can try and make the best of it. But if you can get one erected on a roof top by a professional, do so. There's no point spending say €700-1000 on a new TV if the signal you're feeding it is hopeless, best to budget for another €100-150 for someone to do it properly.

And if you haven't got a head for heights or no experience, don't do it - at least not without the right gear and precautions. We don't need more Rod Hulls...

And finally, the hard sell...

To_be_confirmed wrote: »

Also, my own observations with DTT on any sort of aerial is that reception is quite consistent between muxes from the same site, in comparison to analogue for example. I found this from looking at the MPEG2 DTT tests in Dublin where RTE1 analogue would sometimes look much better than RTE2 or vice versa. Hard to get both to work with just rabbits ears if Kippure wasn't available. But the 4 multiplexes usually came in together. That's quite empirical but what is certain is that if one positions any aerial and gets a strong signal then a small level of reflected signal will be presented as noise or else attenuate the signal directly depending on reflections and carriers etc. This will still leave a perfectly good picture even if C/N ratio has been reduced.

It's the variable reflections that really matter as one can't adjust an aerial as a person is walking through a room, or from moving branches in front of the aerial on a windy day.

As for the typical indoor aerials being sold these days... Many of the larger towns and cities have exceptionally good Saorview coverage in comparison to analogue. If there is a Saorview site right beside the large town or city in question then most places will have a window or other where an indoor aerial would work. The 5 biggest cities and the likes of Clonmel, Longford, Sligo, Tralee, Wexford and various other spots. But the important bit is the window that works. Not much good if it's the bathroom window;)

Indoor aerials are only good while they're near the TV to use. Otherwise you'd need to stick it in the attic and then putting a proper aerial in the attic or indeed outside/in a shed makes more sense.

You've summed it all up, really. There is a very good chance that an indoor aerial will work if you're in a large town or city. No guarantees, but well worth giving it a whirl. Unlike analogue TV, if it does work the reception should be spot on.
(The impulse noise concern is mainly scaremongering by vested interests. Unless, that is, you use a hairdryer beside the TV or fire up your motorcycle in the hallway. There are, of course, a small minority of situations where it would be an issue.)

Mexecutioner

This guy seemed to think there was an increase in 'passive' gain to be had from amplified aerials (in 2003); http://downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP066.pdf

I'm in no position to dispute his conclusions, but . . .

Kristopherus

I have the Lidl aerial and can get the channels just by having it sitting on my window ledge (inside!!!).And way,way better than the cheapo aerials mentioned by others on this thread.

dellWlan

Kristopherus wrote: »

I have the Lidl aerial and can get the channels just by having it sitting on my window ledge (inside!!!).And way,way better than the cheapo aerials mentioned by others on this thread.

I picked up one of those "cheapo" aerials after reading watty's post on the aerial sticky. I obviously would prefer and recommend a rooftop aerial but the indoor aerial works great sitting on the window sill beside my tv.
In what way is the amplified any aerial better?

It was a great way of getting saorview with very little outlay and was more about curiosity before spending any real money on it. but it's certainly not ideal. Would prefer not to have it sitting in my window and a mobile phone right beside it will cause interference but under normal conditions it's fine.
Although since I'm using it with playTV I don't have any quality figures.

Badgermonkey

dellWlan wrote: »

In what way is the amplified any aerial better?

Only an amp'd indoor aerial works in my front room (facing away from transmitter).

Cheap rabbits ears work in the bedroom facing transmitter.

dellWlan wrote: »

It was a great way of getting saorview with very little outlay and was more about curiosity before spending any real money on it. but it's certainly not ideal.

+1

paddyp

Foil insulation such as kingspan in the cavities of recently built homes is a significant factor in your success with an indoor antenna.

I can get perfect signal with a short piece of wire hanging out the back of the telly in one corner of the tv room in the opposite other corner I get almost nothing.

The insulation in the successful corner seems to be acting as a reflector for cairn hill. In the other corner its blocking it almost entirely.

Next door neighbours house which has non foil insulation and same view of the transmitter the signal is perfect everywhere.

NewHillel

Mexecutioner wrote: »

This guy seemed to think there was an increase in 'passive' gain to be had from amplified aerials (in 2003); http://downloads.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP066.pdf

Thanks a bunch for that, it brought back quite a few memories.

It's not that there is an increase in "passive" gain, as such. What John is describing is a methodology for comparing passive and active antennas.

However, the paper describes succinctly why active antennas generally provide a noticeable performance improvement over their passive cousins.

Mike 1972

winston_1 wrote: »

Strange, they've got the money to buy expensive TV equipment but not to pay for a decent aerial which is perhaps 15% of the cost of the TV.

I think youll find that owning ones own house is still a damn sight more expensive than a nice TV though.

lawhec

NewHillel wrote: »

So, it was rubbish. In fact, if you're too near the mast your reception could be worse as, depending on the TX Aerial configuration, you'll be in shadow.

I said the advice was sound, not wherever it was rubbish or not. The fact is that the DTT network for the Republic of Ireland is being designed for reception with a static roof aerial. That's what the coverage maps being published are based on. RF shadows are a separate issue.

NewHillel wrote: »

It is extremely unlikely that this will be an issue as the digital coding technique being used for the Irish DTT is far more resilient than analogue.

Constructive/Destructive interference due to the multiple reception of the same service from different paths is itself immaterial to wherever the broadcast is analogue or digital. It's correct that DVB-T, depending on transmission configurations has more resilience than analogue broadcasts but the phasing of multiple signals can in some cases enhance reception but it worst case scenarios destroy it even in strong signal areas. Because indoor aerials are more prone to receiving reflected signals in close proximity, the phase sum of the signals on that frequency will be random. It's not as if phasing isn't understood by DXers and experienced aerial installers, especially if they are trying to null strong local signals to obtain weaker ones on the same or near frequencies by using two or four aerials in combination.

NewHillel wrote: »

Any such conclusion would only be relevant to the particular amplified indoor aerial tested. This technology has improved greatly in recent years and the cost has fallen dramatically. (Can you remember any details, as I wouldn't mind following this up?)

It was conducted under Ofcom in 2003 or 2004, so now a while back but they used a variety of amplified and unamplified aerials using the multiplexes at Crystal Palace in London which had just been upgraded to an ERP of 20kW involving 16QAM and 64QAM multiplexes. The conclusion was that at best amplified indoor aerials gave an extra 3db advantage over the best unamplified aerial, but this only applied to 16QAM multiplexes. With some amplified aerials their performance was all-round worse than those without amplifiers.

My own experience in using indoor & attic aerials with modest amplifiers (10-14db gain) is that in a few cases, they can take a weak but "clean" signal in that the S/N ratio is adequate but the signal strength is weak and give pictures which weren't possible without it. However those channels are more susceptible to impulse interference and weather conditions.

NewHillel wrote: »

Agreed, but most have a variable gain control that can be turned down, so not a problem in practice.

True, however how many simply crank up and forget, thinking that more is always better and never consider that less could be better? The likes of "33db" are simply a sales gimmick.

NewHillel wrote: »

You are incorrect. They also provide active equalization - hence providing a better impedance match, across a range of frequencies, leading to lower loss.

A decent balun should be able to do the same job at least for UHF? The only way an amplified aerial could be better is through a semi-automatic LC sensing circuit. I've seen indoor aerials contain a manual LC ATU switch abroad, but not at home.

NewHillel wrote: »

(The impulse noise concern is mainly scaremongering by vested interests. Unless, that is, you use a hairdryer beside the TV or fire up your motorcycle in the hallway. There are, of course, a small minority of situations where it would be an issue.)

Impulsive interfere is actually an issue. I don't sell anything, so I've no vested interests here. Certain types of signal problems on analogue are generally immune on DVB-T, but impulse interference on analogue which in many cases isn't annoying is more upsetting on digital causing dropouts and temporary signal loss. Especially if the building electricity wiring is a ring circuit, the switching could take place in another room and still cause interference - I've seen it with my own eyes. Scooters with unsuppressed two-stroke engines the same on a road about 30 metres away. Stronger signals have better immunity but nothing is 100% immune. Any installer using cheap "TV cable" with thin braid coverage for new DTT installiations as opposed to twin-shielded is a cowboy IMO.

lawhec

To_be_confirmed wrote: »

It's more than just people with €700 TVs who are trying to pick up Saorview remember... USB DTT tuners can be bought off the net for less than €15 including delivery and can use laptops or computers people had saved up for already.

Also, my own observations with DTT on any sort of aerial is that reception is quite consistent between muxes from the same site, in comparison to analogue for example. I found this from looking at the MPEG2 DTT tests in Dublin where RTE1 analogue would sometimes look much better than RTE2 or vice versa. Hard to get both to work with just rabbits ears if Kippure wasn't available. But the 4 multiplexes usually came in together. That's quite empirical but what is certain is that if one positions any aerial and gets a strong signal then a small level of reflected signal will be presented as noise or else attenuate the signal directly depending on reflections and carriers etc. This will still leave a perfectly good picture even if C/N ratio has been reduced.

From my own observation of DVB-T reception here in Tyrone, Belfast, and also over in England and in Australia (which involves reception at VHF and well as UHF), I found that unless you can see the transmission mast, getting all six Freeview multiplexes on an indoor aerial in the one spot wasn't easy to do and sometimes not possible. Height above the ground did help, first floor being better than ground floor. In the case of Australia (Brisbane to be more precise), four of the multiplexes were on VHF Band III and one on UHF. It proved impossible even looking out a window towards the direction of the transmitters to get all four VHF multiplexes at once. Closer to home in my attic, I can't get all six Freeview multiplexes at one on a standard indoor aerial from Brougher Mountain in the one position - Mux A being one that seems to be received better in a slightly different direction compared to the other, but when I do move it to be able to receive Mux A, I lose the three I can receive! (There's two that I cannot get )

Of course, with fewer multiplexes, there is less chance of the above happening.

lucernarian

Two points at lawhec:

Firstly, it's technically incorrect to claim that DVB-T modulation or PAL modulation is immaterial to whether a signal is affected by phase cancellations and the likes. When there's 7 odd thousand carriers in the one multiplex some would inherently be completely cancelled out while others may not be completely cancelled even over just 8MHz of bandwidth. Also, the interleaving that exists in DVB-T allows for fluctuating ghosting like with moving trees to be dealt with more effectively than with analogue where the ghost image simply moves somewhat.

I do agree that DVB-T is also prone to ghosting but the extra cushion it has against it means that the circumstances where a signal coming out of phase is only 20 or so dB weaker than the wanted signal are more uncommon circumstances where likely the signal strength in the location is going to be poor and there's lots of obstacles in the way of the TX but not to a nearby obstacle which acts as a good reflector. By this stage, someone would be desperate to use an indoor aerial and would likely have no choice. I.e. an apartment block. Analogue on the other hand can show up much weaker ghosted images on an otherwise good picture.


The second point: for unidirectional broadcasts and if we assume that phase cancellation is indeed harder to achieve with DVB-T, there is virtually no reception issue that can't be cured by an increase in broadcasting power. Also assuming that we can increase it willy-nilly. We know that ERPs being used in Ireland are consistently higher for digital than what would be needed for analogue coverage from the same site, except Cairn Hill I believe EDIT and Mt. Leinster depending on this mast replacement, final ERPs at DSO and reception in Wales. It's not quite representative to make comparisons with firstly a UK situation of six multiplexes (a point you recognise) and their lower pre-DSO digital broadcasting antennae with more directional restrictions etc and obviously with far lower ERPs than Saorview currently.

Also, I don't know what the situation is with Australia and their ERPs and coverage but with VHF, there is a greater actual change in wavelength as you go from one channel to the next than with UHF within the one aerial group especially with Group C/D which I based my experience on. Therefore, the null spots in coverage and ghosting issues etc etc are more likely to affect one channel than another with VHF. But what I highlighted is not going to make a big difference in reality I expect and I expect this will crop up with overspill Freeview reception after DSO. Since the 2nd mux fired up at Kippure and Cairn Hill I've done a little testing and I didn't find any places where only one worked FWIW.

NewHillel

lawhec wrote: »

It's not as if phasing isn't understood by DXers and experienced aerial installers, especially if they are trying to null strong local signals to obtain weaker ones on the same or near frequencies by using two or four aerials in combination.

Indeed, brings back memories, from my early teens, of using a very large loop aerial for DXing North American MW Stations.
Thankfully, in the case under discussion, we are not trying to isolate weak signals in the presence of far stronger ones.

lawhec wrote: »

It was conducted under Ofcom in 2003 or 2004, so now a while back but they used a variety of amplified and unamplified aerials using the multiplexes at Crystal Palace in London which had just been upgraded to an ERP of 20kW involving 16QAM and 64QAM multiplexes. The conclusion was that at best amplified indoor aerials gave an extra 3db advantage over the best unamplified aerial, but this only applied to 16QAM multiplexes. With some amplified aerials their performance was all-round worse than those without amplifiers.

That would not be a valid conclusion from a lab test or field trial. What it could have showed was that, of the sample of indoor aerials that they tested, the most effective amplified aerial gave a 3db adadvantage over the most effective unamplified aerial, using a particular receiver.
The distinction I have just made is not trivial. Amplified aerials have improved in performance over the past number of years. Also, they are more effective with some TV's than with others, depending on the Noise Figure of the front end.

lawhec wrote: »

My own experience in using indoor & attic aerials with modest amplifiers (10-14db gain) is that in a few cases, they can take a weak but "clean" signal in that the S/N ratio is adequate but the signal strength is weak and give pictures which weren't possible without it.

In this case the amplifier is compensating for the loss in the downlead, a much more straightford proposition.

lawhec wrote: »

A decent balun should be able to do the same job at least for UHF? The only way an amplified aerial could be better is through a semi-automatic LC sensing circuit. I've seen indoor aerials contain a manual LC ATU switch abroad, but not at home.

The impedence matching circuitry in a (good quality) Amplified Indoor Aerial is far more sophisticated than a BAlun or simple Aerial Tuning Unit.

lawhec wrote: »

Impulsive interfere is actually an issue. I don't sell anything, so I've no vested interests here. Certain types of signal problems on analogue are generally immune on DVB-T, but impulse interference on analogue which in many cases isn't annoying is more upsetting on digital causing dropouts and temporary signal loss. Especially if the building electricity wiring is a ring circuit, the switching could take place in another room and still cause interference - I've seen it with my own eyes. Scooters with unsuppressed two-stroke engines the same on a road about 30 metres away. Stronger signals have better immunity but nothing is 100% immune. Any installer using cheap "TV cable" with thin braid coverage for new DTT installiations as opposed to twin-shielded is a cowboy IMO.

Of course its an issue, whether its "those Scooters" or a Hair Dryer. But, in reality, not much of an issue where the signal strength is adequate.
Even with very weak signals the DVB-T signal is more resilient than with analogue.

lawhec

to be confirmed: the matter of phasing of multiple signals reaching an aerial on the same frequency is a matter of physics - DTT can only be engineered to help combat this problem in tandem with others which can weaken reception. To take an extreme example, if an aerial receives two signals from the same transmitter, one direct and another of the same strength reflected from a nearby building that is 180 degrees out of phase, then the sum of the two signals will always be zero, cancelled out. No signal. Less extreme cases can still play havoc with signal strengths across different frequencies as the sum of reflections along with the direct signal will vary the phase effect. In some cases, where on analogue very close reflections can cause very tight ghosting making the picture look soft, on digital it can help reinforce reception provided all signals received are within the guard interval.

Newhillel: I agree that amplified aerials can show an improvement in reception where the aerial is mounted outdoors as described in the linked BBC R&D document (I'm assuming outdoor because of the talk of gain values before amplification that are consistent with outdoor aerials), but I'm still not convinced about their usefulness on indoor aerials in most cases - there may be some situations where it could be useful but others where it makes no difference or worse. If I can get my hands on one or two in the near future I might test them myself in a few different places.

NewHillel

@lawhec

I'm not sure what point you're making re phasing and multiple signals. Nobody is disputing the mechanism. The point made was that DVB-T signals are more resilient to the effects of same. They are.

Your assumption re outdoor antennas being the basis of the BBC R&D Paper is incorrect.

Anyway, the advice to the general public, is:

1. Try your existing external aerial, if present.

2. Try an Indoor Aerial.

3. Try a new "Digital" Aerial on the existing aerial cable, if present.
(Assuming the existing cable is in good condition and it is difficult to run a new one.
If you are doing this yoursel, use an Analogue Channel, while it is stil available, to align the antenna for best reception.)

4. If you must run a new cable, use high quality, double shielded.

(Methinks this particular horse has been flogged to death.)

Ronnie Raygun

NewHillel wrote: »

Try a new "Digital" Aerial

What exactly would you say qualifies as a 'digital' aerial (and I'm not one of these people who instantly dismiss the idea)?

winston_1

As has been said many times, there is no such thing as a "digital aerial".

NewHillel

Ronnie Raygun wrote: »

What exactly would you say qualifies as a 'digital' aerial (and I'm not one of these people who instantly dismiss the idea)?

An aerial capable of picking up the Sorview Service, no more, no less.
(It amuses me no end the lengths that some posters will go to to correct perceived misconceptions about "digital aerials" - hence why I deliberately used the term! It really doesn't matter a toss what "it" is called. The vast majority of people understand what is meant. On the other hand, some of the poor "advice" handed out really does matter, as it can mean unnecessary cost for people who are under enough pressure, as it is.)

watty

It's called Trolling. As it is the pedantic hair splitting.

The experience in UK is that "cowboys" and Marketing slime using the term "Digital Aerial" to sell junk the viewer doesn't need. You are doing no service to anyone.

http://www.paras.org.uk/04-aerial.shtml

Unless the Amplified indoor aerial has much lower noise figure than most on sale and the TV RF front end has a poor NF, an amplified indoor makes from no difference to very little. Two cheap €2 indoor aerials on a combiner may act better. Ofcom did trials. You also misrepresented what the BBC document says.

I used to work in BBC, I know what they and RTE think of indoor aerials and particularly Amplified ones. I know what the Engineering people in both places would like to do to people that encourage the term "Digital Aerial".

If a cheap indoor aerial (amplified or not) works, fine. But on Digital, unlike analogue, it's not possible for most people to know how much working margin they have. It's not worth spending any time and money on. If the TV doesn't work with a piece of coax with screen rolled back exposing 6" / 10cm of inner insulation, then it won't be reliable with an indoor aerial

Plug ......... coax ...................... Screen push back over outer of coax ... Inner
]+++++++++++++++++++++++++++++++++++++++++++++++=======

---

] plug
++ Coax (about 3' or 1m minimum and 10' or 3m maximum)
== Screen pushed back over outer of coax (about 6"/10cm)
-- Inner insulation and inner wire (6" / 10cm)

No more than 6dB to 12dB gain is much use in indoor amp gain unless you are driving a long extension cable or splitters. 20dB or more certainly just increases vulnerability to interference.

lucernarian

Whoa now, I think the fact that the word digital was in inverted commas suggests to me that NewHillel was simply referring to those aerials which describe themselves as digital ready (and I don't agree with aerials descriptions talking about being suitable for DTT), rather than suggesting there is a different type of aerial for DTT.

I've also read discussions on this and arguments have been made on the basis of baluns and impedance matching being of more importance for DTT than with analogue reception and that is a matter of opinion as to what people think is acceptable interference to their analogue signal versus their DTT reception.

Watty, you know well that if you think there's trolling going on there's a report button to deal with it... Mentioning "trolling" in a thread just serves as a distraction to a topic that I'd like to see discussed further.

NewHillel

watty wrote: »

It's called Trolling.

What exactly are you referring to?

watty wrote: »

Unless the Amplified indoor aerial has much lower noise figure than most on sale and the TV RF front end has a poor NF, an amplified indoor makes from no difference to very little. Two cheap €2 indoor aerials on a combiner may act better.

You have changed your position.
The OP asked for advice on The Silvercrest Amplified Indoor Aerial. Your response was "It's no better than a €2 model." You are now saying that "Two cheap €2 indoor aerials ON A COMBINER may act better. Indeed they may, but are you seriously suggesting that this is a better approach? I sincerely hope not.

Oh, and would you please point out EXACTLY where and how I misrepresented what the BBC document says. (Wild allegations are not helpful. If I got something wrong I'll happily correct it.)

NewHillel

To_be_confirmed wrote: »

Whoa now, I think the fact that the word digital was in inverted commas suggests to me that NewHillel was simply referring to those aerials which describe themselves as digital ready (and I don't agree with aerials descriptions talking about being suitable for DTT), rather than suggesting there is a different type of aerial for DTT.

Of course that was exactly what I meant.

For the layman, there is nothing wrong with describing an aerial as digital ready. What is entirely wrong is encouraging consumers to make unnecessary purchases, when they may be entirely unnecessary.

Watty is correct when he says "But on Digital, unlike analogue, it's not possible for most people to know how much working margin they have." The pertinent question then is "Does this matter?". I would suggest not. With terrestrial signals, the potential for large variations in signal strength is, unlike with satellite signals, small. (To be clear, I'm talking about local transmissions within range of an indoor aerial. The situation is very different with more distant transmissions where tropospheric ducting can cause all sorts of funny effects.) Anyway, the small cost of installing an indoor aerial means that little is lost, if it doesn't work out.

Agent Smith

I'm watching saorview with a bent coat hanger


Works fine :-)

NewHillel

Agent Smith wrote: »

I'm watching saorview with a bent coat hanger


Works fine :-)

Now that is a "small" cost.

Out of interest, can you see the mast? :eek:

Gerry Wicklow

A mast for a coathanger???
:)

watty

NewHillel wrote: »

What exactly are you referring to?



You have changed your position.
The OP asked for advice on The Silvercrest Amplified Indoor Aerial. Your response was "It's no better than a €2 model." You are now saying that "Two cheap €2 indoor aerials ON A COMBINER may act better. Indeed they may, but are you seriously suggesting that this is a better approach? I sincerely hope not.

Oh, and would you please point out EXACTLY where and how I misrepresented what the BBC document says. (Wild allegations are not helpful. If I got something wrong I'll happily correct it.)

I have not changed my position. For almost everyone a €2 indoor aerial as long as it's got the UHF loop, is just as good. The Lidl one is a waste of money, as are all such aerials. One-For-All has the cheek to charge £50 for one and label it as Digital HD.

If an amplified indoor aerial is better the TV is seriously rubbish. If an Indoor aerial works, fine. But it's not the purpose of the forums to mislead people or get them to waste their money.

STB

I have read this thread with interest. RTE would be of the view that in general Saorview is designed for use in most areas with an outdoor aerial. This is to stop people running out and getting crap indoor aerials and there are some very bad ones (where a coat hanger would better) and even the good ones will not work for those that will require an outdoor aerial regardless.

Having said that the postioning of even the crapest amplified aerials is actually the most important aspect to good reception. They cannot be placed on top of the TV, something that people do naturally. They must be placed by on window cill. Most of these aerials dont even have a long enough fly lead to get to a suitable cill and still be powered by mains. Hence you have people placing aerials in the wrong places, ie the centre of the room and will be subject to interference from the fridge, light switches, mobile phones, electronic lighters, power pumps, anything electrical basically.

In places like Dublin with adequate spacing between a window cill and outside buildings you will pick up DTT no problem easily with an indoor aerial. You do not have to "see" Three Rock Mountain. Visual siting of the TX site is not a requirement.

Using a coathanger will work. Infact right now being away from my own setup I am watching the game with a DTT box that has a 5v phantom power. I have a coathanger positioned up against the window cill a foot off the ground. The result, 40% signal strength. No breakup. Analogue wouldnt produce similar results. I have said it before and I'll say it again, DTT broadcasts will get into places that analogue didnt adequately before and as people discover that there is no snowy picture and a perfectly watchable picture, more will be looking for a Free combined package of both the UK and Irish stations in one. That is the basic difference between both.

Sky are worried and they have every right to be. It surprising what people will sacrifice when they are shown the two side by side. Most people seeing DTT for the first time say cant get over the crystal clarity and that it doesnt involve paying bills to third parties.

NewHillel

watty wrote: »

I have not changed my position. For almost everyone a €2 indoor aerial as long as it's got the UHF loop, is just as good. The Lidl one is a waste of money, as are all such aerials. One-For-All has the cheek to charge £50 for one and label it as Digital HD.

If an amplified indoor aerial is better the TV is seriously rubbish. If an Indoor aerial works, fine. But it's not the purpose of the forums to mislead people or get them to waste their money.

I'm not going to waste my time arguing with you further. Now, would you please point out EXACTLY where and how I misrepresented what the BBC document says. Else, you might have the decency to withdraw the comment.

Badgermonkey

watty wrote: »

If an amplified indoor aerial is better the TV is seriously rubbish. If an Indoor aerial works, fine. But it's not the purpose of the forums to mislead people or get them to waste their money.

Can only offer anecdotal evidence watty.

LG 32LD450.

One for all amplified works, only when amplification is turned to full and aerial is placed beside window (facing away from transmitter)

In the interests of saving folks from wasting money, indoor aerials should not be casually dismissed as a viable alternative.

They may well be technically inferior in every possible way but if they display the service with consistency, majority of folks simply will not care.

NewHillel

@Watty
I note that the ISSA also use the term "Digital Aerial".
Care to comment?

watty wrote: »

It's called Trolling. As it is the pedantic hair splitting.

The experience in UK is that "cowboys" and Marketing slime using the term "Digital Aerial" to sell junk the viewer doesn't need. You are doing no service to anyone.

NewHillel wrote: »

An aerial capable of picking up the Sorview Service, no more, no less.
(It amuses me no end the lengths that some posters will go to to correct perceived misconceptions about "digital aerials" - hence why I deliberately used the term! It really doesn't matter a toss what "it" is called. The vast majority of people understand what is meant. On the other hand, some of the poor "advice" handed out really does matter, as it can mean unnecessary cost for people who are under enough pressure, as it is.)

Ronnie Raygun wrote: »

What exactly would you say qualifies as a 'digital' aerial (and I'm not one of these people who instantly dismiss the idea)?

bodonnell

Evening folks,
I am currently using an aerial I got of ebay for about 14 euro, it's cylindrical with a magnetic base & is currently stuck to back of tv & is working perfect, it's not amplified. I live in co. Limerick

dellWlan

bodonnell wrote: »

Evening folks,
I am currently using an aerial I got of ebay for about 14 euro, it's cylindrical with a magnetic base & is currently stuck to back of tv & is working perfect, it's not amplified. I live in co. Limerick

Any chance of a pic? that's stoked my curiosity. I know magnetic fields impacted on old CRT tv screens, are modern plasma/LCD/LEDs immune? Do magnetic fields affect digital reception?

Obviously not in your case but in general is there the potential to?

bodonnell

If u search ebay for 'digital freeview 30dBi Antenna' u should get all details. Aerial is desribed as amplified but there is no apparent power source.

Joe7

bodonnell wrote: »

Aerial is desribed as amplified but there is no apparent power source.

Magic! (It magiced 14 quid out of your pocket anyway).

bodonnell

Maybe it is magic but it works & for a lot less than 'one for all' or similar