4g mobile phone network rumoured very likely to severely affect freeview tv receptio

[chris murphy]

"Hello All",

I read a few Days ago that the 4G Mobile Phone Network `Second Phase` of Transmitter installations / Upgrades is VERY likely to cause SOME areas severe problems with Freeview Reception - `Totally Blacking Out` some areas !

I noticed that one of the areas likely to be MOST affected is MY area - from the Crystal Palace [SE London] Transmitter !

I have already had BIG Problems with Freeview reception since the SECOND DAY of the Digital Switchover in My area - I had almost perfect Freeview reception on ALL of the Freeview enabled TV`s in My Home for YEARS before that DAY - ever since at the slightest hint of any `Bad Weather` I have problems with the Freeview reception - the ITV Channels - Channel 4 - Channel 5 and many more Channels become completely Unwatchable.

I read in another Newspaper article that there will be `Filters` available for approximately £20.00 which I assume means that they are designed to `Block` the 4G Signals [?].

But although I am NOT at all knowledgeable about Mobile Phone Transmissions and their affect on Digital TV Signals / Reception - I just cannot believe that something that is sold for £20.00 approx. could be Technically Advanced enough to Block a particular Transmission Frequency / Signal - ?

EDIT - I HAVE NOW READ THAT THESE `FILTERS` COULD COST OVER £200.00 - THIS SEEMS TO BE REFERRING TO EQUIPMENT THAT WOULD REQUIRE A TV `ENGINEER` TO INSTALL - !

Newspaper Article from the Independant:

http://www.independent.co.uk/news/uk...v-7899834.html



I wondered if any Members were knowledgeable about this matter - I believe that this 4G `Second Phase` is due to be started in early 2013 - I would like to at least know what I would have to purchase to `Try` when this ominous / possible `Black Out` of my TV`s Freeview Reception occurs.

Although I have Sky in some rooms We still want to be able to Receive and View Freeview in other rooms of My Home - without paying to install FreeSat.


I cannot believe that there has not been more publicity about this - I assume that the Government have made so much Money out of Licensing the `4G Network Frequency / Signal Band` that they could not care less about a few Million [?] Freeview TV Viewers [articles quote `2 to 3 Million Households`] - !


EDIT:

I have just found this quote on the 4G Britain website - FAQ`s section:

http://www.4gbritain.org/faq/


QUOTE:

Will 4G interfere with my Freeview reception?

News reports have suggested that 4G mobile services may affect Freeview reception. The fact is 4G technology does not in itself affect Freeview or other television reception.

However, the future use of airwaves in the 800MHz band that is being transitioned from TV broadcast to mobile services presents the potential for Freeview services to be affected.

This is because current TV receivers or Freeview boxes are designed to receive airwaves which have previously been used by TV.

Any impact to services will only happen in certain geographical areas, but we cannot yet predict where. This may occur from 2013.

Fortunately, there are fixes for any problems for TV viewers and in most cases these fixes are very simple and free.

The media and communications industry regulator, Ofcom and the government are proposing that a new organisation will be set up to inform and assist affected consumers on how to restore TV services and they have also pledged funding for this.


4G will be delivered cross other airwaves too, such as 900 MHz, 1800MHz or 2.6 GHz, and this will not disrupt Freeview services.


END QUOTE

This does NOT tell people WHAT these `Fixes` are - when are we to find out ?

I don`t want to `Wait and see` IF My Freeview TV will be `Blacked Out` and then try and find out what I can `Order` [alomg with perhaps Millions of other Households !] and then have to wait for a Delivery !


What particularly annoys Me is that Freeview / Digital Television Broadcast was rolled out obviously knowing
that this 4G Use of the same Frequencies that Freeview Receivers can pick up would affect possibly Millions of Households.

And the fact that where they do pick up 4G Transmissions / Signals this can severely disrupt / Block Out the Freeview TV Reception !

The Revenue for the 4G Licences obviously came first.


Regards,


Chris​

 

[SparkyJoe]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

The fix is that you get an old sky dish and freesat

 

[chris murphy]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

The fix is that you get an old sky dish and freesat

"Hello Sparky Joe",


Thanks for replying.

I have 5 Televisions - 2 of which We watch Sky on - Living Room and Main Bedroom - BUT We have 3 other TV`s which rely on Freeview only - Two of these have Set Top Boxes for Freeview - One has a Freeview tuner within the TV.

I had the Freeview set up on ALL of the TV`s for YEARS before the Digital Switchover with almost perfect reception - then on Day 2 of the switchover the problems STARTED ! - since then there have been LOADS of problems with the reception.

I have 3 Aerials and a Sky `Ordinary` Satellite Dish - the LAST thing I want is to have to install 3 FreeSat Satelitte Dishes !


Thanks again for your interest and reply.


Regards,


Chris

 

[grantr37]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

the analogue TV frequency spectrum (spread) was sold for the purpose of 4G, the above mention from the website placed on here by chris (thanks) is basically an admission to the general public (kind of a so what shrugged shoulders) response by the company more or less saying "current freeview boxes" and all that.......so basically its a case of " Blah, buy a new more modern box Blah" in other words don't give a funny wugger...

"in itself does not affect reception"..............actually it does.....

 

[BigTom83]

Apparently the new 4g network will work on the frequency currently used by digital tv (800 MHz) and tv will be moving to a new frequency (700 MHz), which apparently only means u need to rescan your channels on your freeview box. No need to buy new equipment. But this is further down the line not now. Something to do with joining rest of Europe's frequency or something. Read it in paper.

 

[chris murphy]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

the analogue TV frequency spectrum (spread) was sold for the purpose of 4G, the above mention from the website placed on here by chris (thanks) is basically an admission to the general public (kind of a so what shrugged shoulders) response by the company more or less saying "current freeview boxes" and all that.......so basically its a case of " Blah, buy a new more modern box Blah" in other words don't give a funny wugger...

"in itself does not affect reception"..............actually it does.....

"Hello grantr37",


Although I knew a few Years ago why the Digital TV Switchover was being done - to `Free Up to thje Analogue Frequencies` for use by Mobile Phones - I still cannot believe that people who were KNOWN to Live within areas that will be affected by the use of the 800 Hz [?] Frequencies were not able to purchase specific equipment when buying Set Top Boxes etc. to prevent the `Interference` from the 4G Mobile Phone Networks on their Freeview TV Reception.

I am fairly sure that the 4G Mobile Phone Transmitter locations have been known for YEARS - because of the `Development Stratagies` that have been involved during the 4G Planning Process - so there is no excuse for `Not knowing what areas will be affected` !


I am now wondering whether SKY - on the 847 Frequency will be affected by this Use of the 800 Hz [?] Frequency ?

Like many People I have a mixture of both TV`s with a built in Freeview Tuner and Set Top Boxes for the older TV`s.

On one of the TV`s - a 2 Year old 46" Samsung LCD TV [with built in Freeview] that I paid £1000.00 for - I had to connect a Digital Video Recorder to enable Me to be able to WATCH or Record Freeview Channels - it obviously has a much better Freeview Tuner than the £1000.00 TV !

Immediately during Day 2 of the Digital Switchover I could no longer get a Good Reception at all on that TV with its own Freeview Tuner !


Even now - as I write it is raining heavily - I cannot get any watchable Freeview Reception from ANY TV in the House - 5 TV`s ! - This has been the case in varying degrees of `Signal Disruption` when there is Bad weather since DAY 2 of the Digital Switchover here.

Luckily I have Sky in the Living Room and Main Bedroom - so it is not a `Disaster` - except that people cannot watch TV`s in the other Bedrooms - `A Backward Step` in our Home`s TV Reception !


BUT - Before the Digital Switchover I had Great Reception on Freeview on ALL of the TV`s - irrespective of the Weather - even during `Blizzards` !


This is BEFORE the 4G probable problems - which MAY AGAIN mess up EVERY TV / Set Top Box in the House !


So much for the Digital TV `Improving TV Reception` !


Sorry about the Rant.


Regards,


Chris

 

[chris murphy]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

Apparently the new 4g network will work on the frequency currently used by digital tv (800 MHz) and tv will be moving to a new frequency (700 MHz), which apparently only means u need to rescan your channels on your freeview box. No need to buy new equipment. But this is further down the line not now. Something to do with joining rest of Europe's frequency or something. Read it in paper.

"Hello Big Tom83",


Thanks for your reply.


I hope that You are correct about the Freeview TV Frequencies just being `moved`.

If that is the case the Newspapers that have `Reported` what I read should be severely admonished for `Alarming the Public` !

Since I read about what I wrote in My original Post on this subject I have been looking online for further details about this - EVERYTHING that I have read has made Me MORE worried that ALL of My Home`s TV`s WILL be badly affected !


Although obviously I do hope that what you mentioned is correct and that I `Have nothing to worry about` - I will still be researching further to TRY and at least have ONE `Filter`/ Filtered Set Top Box ready for `Early 2013` when these 4G Signals are stated to `possibly cause some interference to Freeview TV`s`.

AND hopefully know of a source to quickly obtain more of these items.

Thanks again for your message.


Regards,


Chris

 

[mhar]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

Ooh!
Lte (long term evolution) is the name given to this problem. 4G now (in some areas) 5G in 2017 and 6G in 2020 will all start using frequencies in the old uhf tv spectrum. For the majority of people this will not be a problem and for a lot of people affected the cure will be a 50p filter.
There are a number of issues and therefore a number of cures although it is recognised that some people will no longer be able to receive freeview and have to use a different platform for tv reception.
The mobile phone downlinks are (by european if not worldwide convention) using the lower channels vacated by the tv transmitter operators, are high powered and can easily cause the agc of a tuner to overcompensate reducing the levels of wanted signals to an unusable level. They can also exceed the maximum input levels for amplifiers causing them to stop working correctly. Uhf loopthroughs in many set top boxes are amplified as well and this is the reason believed to be behind sky's decision to disable the rf2 output thereby eliminating the need to have any uhf signals going through a sky box. Sky's magic eye voltage passing distribution units are amplified and therefore susceptible. Remember back a while when it was quite common for people to have better (analogue) pictures through their vcr, this was because of the slight amplification.
The solution is to stop these unwanted levels of mobile phone signals getting to any of the units that could be affected. TV manufacturers are developing tuners that cut off at ch60 as are amplifier manufacturers but current developments are only going to be 'valid' until 5G comes along.
Fitting a filter is the easy solution in most cases. Unfortunately filters do not cut off cleanly and there is always a bit of bleed through - a ch31-59 pass filter will be unable to reject all of ch60. So, off Crystal Palace for instance where all the multiplexes fall within the sub ch40 group, we only need to use a channel 31-40 pass filter and couldn't care less about a bit of adjacent channel bleed through as the adjacent channels do not carry high levels of unwanted signal.
If, however, you are receiving from ch59 (after last May's retune for affected transmitters) then you potentially have a problem as there will be a high level of bleed through from ch60 which could overload the aforementioned pieces of equipment and this is where it will get quite tricky.
I have banged on a bit in the past about the misuse / unnecessary use of amplifiers, hopefully people can now see a reason to heed the warnings.
If only the mobile phone downlink (high powered) and uplink (lower powered) frequencies were the other way round then the problems would be greatly reduced but then uk phones would not work abroad and vice versa. To the mobile phone operators these new frequencies are highly desirable as the lower the frequency the better the signals travel through walls and the lower the frequency the less the attenuation thus improving reception.
Mike

 

[JD6400]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

A little off topic , but not that far !?
I was told by one of our blokes that he recons he had read somewhere that the standard mobile phone reception in the UK is being sacrificed to give more power to the new 4G network .
Now I do not know if this is just one of those scare stories , but I have noticed a distinct lack of reception lately on the O2 network in all sorts of new places across the country !?

Have others heard of , or noticed this as well ?

 

[ruston]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

A little off topic , but not that far !?
I was told by one of our blokes that he recons he had read somewhere that the standard mobile phone reception in the UK is being sacrificed to give more power to the new 4G network .
Now I do not know if this is just one of those scare stories , but I have noticed a distinct lack of reception lately on the O2 network in all sorts of new places across the country !?

Have others heard of , or noticed this as well ?

I am on 02 and it is little better than useless, it seems to be getting worse by the day . I left Orange/EE to go to this mob and have tied myself down for a year .I will not be signing up for another term.

 

[chris murphy]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

Ooh!
Lte (long term evolution) is the name given to this problem. 4G now (in some areas) 5G in 2017 and 6G in 2020 will all start using frequencies in the old uhf tv spectrum. For the majority of people this will not be a problem and for a lot of people affected the cure will be a 50p filter.
There are a number of issues and therefore a number of cures although it is recognised that some people will no longer be able to receive freeview and have to use a different platform for tv reception.
The mobile phone downlinks are (by european if not worldwide convention) using the lower channels vacated by the tv transmitter operators, are high powered and can easily cause the agc of a tuner to overcompensate reducing the levels of wanted signals to an unusable level. They can also exceed the maximum input levels for amplifiers causing them to stop working correctly. Uhf loopthroughs in many set top boxes are amplified as well and this is the reason believed to be behind sky's decision to disable the rf2 output thereby eliminating the need to have any uhf signals going through a sky box. Sky's magic eye voltage passing distribution units are amplified and therefore susceptible. Remember back a while when it was quite common for people to have better (analogue) pictures through their vcr, this was because of the slight amplification.
The solution is to stop these unwanted levels of mobile phone signals getting to any of the units that could be affected. TV manufacturers are developing tuners that cut off at ch60 as are amplifier manufacturers but current developments are only going to be 'valid' until 5G comes along.
Fitting a filter is the easy solution in most cases. Unfortunately filters do not cut off cleanly and there is always a bit of bleed through - a ch31-59 pass filter will be unable to reject all of ch60. So, off Crystal Palace for instance where all the multiplexes fall within the sub ch40 group, we only need to use a channel 31-40 pass filter and couldn't care less about a bit of adjacent channel bleed through as the adjacent channels do not carry high levels of unwanted signal.
If, however, you are receiving from ch59 (after last May's retune for affected transmitters) then you potentially have a problem as there will be a high level of bleed through from ch60 which could overload the aforementioned pieces of equipment and this is where it will get quite tricky.
I have banged on a bit in the past about the misuse / unnecessary use of amplifiers, hopefully people can now see a reason to heed the warnings.
If only the mobile phone downlink (high powered) and uplink (lower powered) frequencies were the other way round then the problems would be greatly reduced but then uk phones would not work abroad and vice versa. To the mobile phone operators these new frequencies are highly desirable as the lower the frequency the better the signals travel through walls and the lower the frequency the less the attenuation thus improving reception.
Mike

"Hello Mike",

Thanks very much for your very informative message.


You mentioned that people who live in the Crystal Palace Transmitter area should be using a channel 31 to 40 Filter to prevent the 4G Mobile phone transmissions from interfering with their Freeview / Digital TV reception.


I did try to research what 4G Filters I would need for the Crystal Palace transmitter area but I could not find any really specific product information - this was during last November / December and also in January / February of this Year.


As I have been a very good Customer of Maplin last December / January I contacted them to ask why they were NOT selling 4G Filters as the probable disruption of TV`s countrywide by the 4G Mobile phone network was imminent - their Customer Services department and Purchasing department then informed Me that they were awaiting delivery of Labgear 4G LTE 800 Filters which would definitely be suitable for the Crystal Palace transmitter.


Shortly after that when the 4G Filters became available - Maplin WEBSITE ONLY at that time - Now available in Stores - I purchased a couple of these 4G Filters from Maplin.


I got 2 types:

One is a `Labgear LTE 800 Filter - Channel 59 Filter` - F4GAHS [Maplin No: N27NY] and is specified as `passes frequencies 5 - 782 MHz - Rejects 791 - 862 MHz`.

The other type is a Labgear LTE 800 Filter - F4GC [Maplin No: N26NY] - specified as `passes 5 - 782 MHz - Filters 791 - 1000 MHz`.


These were far from `50p Filters` - I bought one of each type to try them if I got any 4G interference and from memory they cost about £23.00 - I think that one was £14.99 and the other was £7.99.



Obviously most of 2013 has now elapsed and I have NOT been able to establish that there has been any 4G Network interference to my Home`s TV`s [?].

There has been plenty of interference to the Freeview / Digital reception especially during rainfall - this happens now even when the rain is not particularly heavy - previously it was happening only during heavy rainfall.



Mike - I would really value your technical expertise / knowledge in letting Me know whether the Labgear LTE 800 - 4G Filters that I have detailed above are suitable for My TV`s / the Crystal Palace transmitter / Digital channels ?



Thanks for your help with this.


Regards,


Chris

 

[mhar]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

The 50 p filters I referred too wasn't meant as a guide to cost, more that they are very basic (fixed tuning capacitors) and a bit crude but suitable for the majority of people save for those who are receiving from channels adjacent too (or n-2) from the interference. These have to be better engineered as we need a clean a cut off as possible. These basic ilters are going to be given away free to people requiring them so I may not be too far out with my pricing!
I used Crystal Palace as an example as this is the most powerful transmitter in the uk and already transmits in the 31-40 range which is the range that all transmitters will ultimately use. Your original post probably influenced me as well!
Your particular need for a filter will depend on your aerial. About 15 years ago we were advised by the dti that we should use wideband aerials, an aerial which picks up accross the whole of the then uhf spectrum. Yagi type aerials (the most common) are unfortunately biased towards the top end of this spectrum so now are more prone to receiving the coming interference. If yours is a grouped aerial (denoted by a red end cap for group A) then the aerial on it's own should reject 4G interference. For a log periodic you can just snip off the smallest what looks like a reflector but is actually part of the dipole. However the cable may pick up these frequencies if you are unfortunate, hence the introduction of triple screened cable. For Crystal Palace pretty much any filter will do, however by choosing a 31-40 pass filter you should not have to worry again, certainly for the 2017 change.
The filters you have purchased will stop the 2013 interference but if you have either a wideband aerial or poor cable then you may need to change these in 2017. The direct answer to your question is yes they have sold you the correct filters for 4G interference but possibly not suitable for 5G, 6G etc.
How come you lose reception in the rain? Probably a stupid question! Could you give me details of your aerial system with photos please and any other relevant information. I assume that you have had the obvious checked and that no water is entering your cable. Moisture in the atmosphere can cause problems in a few circumstances, not so much since switchover though

 

[chris murphy]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

The 50 p filters I referred too wasn't meant as a guide to cost, more that they are very basic (fixed tuning capacitors) and a bit crude but suitable for the majority of people save for those who are receiving from channels adjacent too (or n-2) from the interference. These have to be better engineered as we need a clean a cut off as possible. These basic ilters are going to be given away free to people requiring them so I may not be too far out with my pricing!
I used Crystal Palace as an example as this is the most powerful transmitter in the uk and already transmits in the 31-40 range which is the range that all transmitters will ultimately use. Your original post probably influenced me as well!
Your particular need for a filter will depend on your aerial. About 15 years ago we were advised by the dti that we should use wideband aerials, an aerial which picks up accross the whole of the then uhf spectrum. Yagi type aerials (the most common) are unfortunately biased towards the top end of this spectrum so now are more prone to receiving the coming interference. If yours is a grouped aerial (denoted by a red end cap for group A) then the aerial on it's own should reject 4G interference. For a log periodic you can just snip off the smallest what looks like a reflector but is actually part of the dipole. However the cable may pick up these frequencies if you are unfortunate, hence the introduction of triple screened cable. For Crystal Palace pretty much any filter will do, however by choosing a 31-40 pass filter you should not have to worry again, certainly for the 2017 change.
The filters you have purchased will stop the 2013 interference but if you have either a wideband aerial or poor cable then you may need to change these in 2017. The direct answer to your question is yes they have sold you the correct filters for 4G interference but possibly not suitable for 5G, 6G etc.
How come you lose reception in the rain? Probably a stupid question! Could you give me details of your aerial system with photos please and any other relevant information. I assume that you have had the obvious checked and that no water is entering your cable. Moisture in the atmosphere can cause problems in a few circumstances, not so much since switchover though

"Hello again Mike",

Thanks very much for replying so quickly and for answering my question about the Labgear 4G Filters that I purchased from Maplin.

With regard to the interference on my Freeview channels / Digital TV channels during rainfall:

This only started on DAY TWO [slight interference on Day one] of the Digital TV switchover for the London area !

I had Freeview on all of the TV`s in my Home for at least 3 Years before that - all with almost perfect reception - and I had never noticed any interference during rainfall - or even during heavy snowfall !

I have Group A Aerials - [NOT `High Gain`] - which I was told were as required / specified for the Crystal Palace transmitter - and the aerial cable is `Specification 100`/ Double screened - please excuse Me that I cannot remember the exact term for that but I know that it was the `Best Quality` that was readily available about 4 Years ago.

The Aerials and cables were installed by Me when I had scaffolding up at my Home for a new Roof to be fitted so I know that they are secure - aligned correctly and that the cables are well clipped throughout their length to avoid chaffing damage etc.

When the interference problem started I had the Aerial waterproof cable connection enclosures checked by a friend who went up onto My Roof [using roof ladders] - I could not go up personally as I was suffering with a severe Back problem.

They were still perfectly in tact and preventing any water ingress - We also checked the alignment using a cheap Signal Meter that I had used when I originally installed the 3 Aerials - the alignment had not changed and the Aerials were still receiving a strong signal.

I cannot attach any Photo`s as I never thought to take any when I was fitting the Aerials and I would have to go too far away from my House to be able to see one of the Aerials to be able to take a Photo with my Mobile phone - the other two Aerials cannot be seen well enough from within my Garden to be able to take Photos.

Also as I am sure You know Photos taken with a Mobile phone from any distance - especially of something like an Aerial would not show enough detail to be able to see it properly.

Putting it bluntly - The Freeview / Digital TV reception on my Home`s TV`s has never been the same as it was BEFORE DAY TWO of the London area Digital TV Switchover !


I posted quite a lot about this on here at the time - I will try and find the original message / plea for help and edit in the link here:

EDIT - HERE IS THAT ORIGINAL THREAD ABOUT MY FREEVIEW / DIGITAL TV RECEPTION BEING MUCH WORSE SINCE THE DIGITAL TV SWITCHOVER IN THE LONDON AREA:

http://www.electriciansforums.co.uk...rum/55434-my-tv-s-freeview-channels-have.html

Mike this is a LOT of reading as there was a lot of replies and Me answering the replies - there were so many questions and answers that I could not go through all of them again here.


Thanks again for your interest and for your informative replies Mike - I really appreciate your help.

Regards,


Chris

 

[mhar]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

Hi,
Had a bit of a read. My pc doesn't like that thread and keeps shutting down, you must be jinxed!
I have virtually no experience of tv reception in cities but hopefully there are parallels.
When we receive from the Welsh transmitters (I live in N Devon) our reception can be affected when we have lowish cloud and a high tide (seriously!). This is because not only are we receiving a signal direct from the transmitter, we are also receiving another/multiple signals that have bounced up and down between the water and the clouds. We also get this when receiving through valleys, there are certain areas where I will not attempt to receive off certain transmitters except for in the summer months when plant / tree growth is at its maximum and tv reception at its worst. Basically the water content is causing reflections again and we get signals arriving out of phase.
As you correctly state, this problem has been massively reduced since digital tv arrived due the error correction data transmitted. However it can still be a real problem. Televes make aerials specifically designed with the Spanish valleys in mind - the dat series. However my favourite was the vision stealth array (until they decided to save 20p manufacturing costs meaning we can no longer mount them on 2" poles) and is probably the most suitable for you. Basically this is two log periodics sat side by side and combined by using equal length cables. Crudely put the theory is that they both pick up the desired signal from the transmitter and if we assign this a value of say 10 units, then 10 + 10 =20. Each aerial will also pick up reflections but at lower power, say 7. However these signals are time delayed because they are reflections and will therefore arrive at each aerial at a slightly different time as they are not being received from the front of the aerial. Therefore we have nothing to add the 7 to, we just have a 7 and another but slightly different 7. So, if using one aerial we present to the tuner a 10 of good signal plus a 7 of unwanted signal giving a signal to noise ratio of 10:7. With an array we are presenting to the tuner a 20 of good signal plus a 7 of unwanted giving a signal to noise ratio of 20:7 which the tuner's error correction data processing is more likely to be able to do something with
Additionally problems can be encountered in very strong signal areas by the opposite of ghosting, the tuner being presented with a signal earlier than the main signal. Personally I have not encountered this since digital but it could be a problem. However as I do not see how wet weather would make this worse, my money is on your s/n ratios.
Why have 3 aerials? Just the way it turned out? There is absolutely no point in giving your tuner more signal than it needs. All that happens is the agc of the tuner knocks this signal back down.
Without being on site with my meter everything is speculation. You need a professional with a spectrum analyser who properly understands the propagation of radio waves and is able to interpret the measurements that his meter gives. It is possible to work out what is causing reflections from the information given by the meter, a lot easier for me where it may be a church or a hillside, in a city with many buildings I wouldn't know where to start hence the requirement for a local professional who may then be able to site your aerial / array to minimise these influences.

 

[chris murphy]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

Hi,
Had a bit of a read. My pc doesn't like that thread and keeps shutting down, you must be jinxed!
I have virtually no experience of tv reception in cities but hopefully there are parallels.
When we receive from the Welsh transmitters (I live in N Devon) our reception can be affected when we have lowish cloud and a high tide (seriously!). This is because not only are we receiving a signal direct from the transmitter, we are also receiving another/multiple signals that have bounced up and down between the water and the clouds. We also get this when receiving through valleys, there are certain areas where I will not attempt to receive off certain transmitters except for in the summer months when plant / tree growth is at its maximum and tv reception at its worst. Basically the water content is causing reflections again and we get signals arriving out of phase.
As you correctly state, this problem has been massively reduced since digital tv arrived due the error correction data transmitted. However it can still be a real problem. Televes make aerials specifically designed with the Spanish valleys in mind - the dat series. However my favourite was the vision stealth array (until they decided to save 20p manufacturing costs meaning we can no longer mount them on 2" poles) and is probably the most suitable for you. Basically this is two log periodics sat side by side and combined by using equal length cables. Crudely put the theory is that they both pick up the desired signal from the transmitter and if we assign this a value of say 10 units, then 10 + 10 =20. Each aerial will also pick up reflections but at lower power, say 7. However these signals are time delayed because they are reflections and will therefore arrive at each aerial at a slightly different time as they are not being received from the front of the aerial. Therefore we have nothing to add the 7 to, we just have a 7 and another but slightly different 7. So, if using one aerial we present to the tuner a 10 of good signal plus a 7 of unwanted signal giving a signal to noise ratio of 10:7. With an array we are presenting to the tuner a 20 of good signal plus a 7 of unwanted giving a signal to noise ratio of 20:7 which the tuner's error correction data processing is more likely to be able to do something with
Additionally problems can be encountered in very strong signal areas by the opposite of ghosting, the tuner being presented with a signal earlier than the main signal. Personally I have not encountered this since digital but it could be a problem. However as I do not see how wet weather would make this worse, my money is on your s/n ratios.
Why have 3 aerials? Just the way it turned out? There is absolutely no point in giving your tuner more signal than it needs. All that happens is the agc of the tuner knocks this signal back down.
Without being on site with my meter everything is speculation. You need a professional with a spectrum analyser who properly understands the propagation of radio waves and is able to interpret the measurements that his meter gives. It is possible to work out what is causing reflections from the information given by the meter, a lot easier for me where it may be a church or a hillside, in a city with many buildings I wouldn't know where to start hence the requirement for a local professional who may then be able to site your aerial / array to minimise these influences.

"Hello again Mike",


Sorry that I could not reply sooner I have only just seen your message at 1300 Hrs on Thursday.


My entire `rant` on the other thread that You kindly read some of was based on the fact that for over 3 Years I had all of my Home`s TV`s set up with Freeview - all of which had great pictures / reception - UNTIL the London area Digital TV Switchover - DAY 2 !


From that Day onwards the Freeview / Digital TV reception has been less good than it was previously and often too bad to watch when it rains - also when We had snowfall last Winter the Freeview reception was completely disrupted - totally unwatchable.


I have Sky TV in my Living Room and Bedroom but the Freeview in the other Bedrooms and Kitchen would not be watchable during bad weather / heavy rainfall [sometimes light rainfall] and although this is not a `Disaster` it is sometimes slightly inconvenient when I have Family or Friends staying at my Home [for them].


For the previous 3 Years or more We had Freeview reception on every TV which was beyond ANY criticism - people used to be amazed at the quality of the picture / reception.


Regarding the 3 Aerials - this is because We have an Aerial on 3 different Roof / Chimneys to connect to TV`s in 3 different parts of my House.

There is no interconnection of these Roof spaces so I cannot run one Aerial cable to a splitter box [correct term ?] in the Roof space and distribute cables to each TV from there.

I do not have any amplified or splitter boxes - all 3 of the Aerial cables go directly to a TV or Freeview set top box.

Nothing has been changed since I set up Freeview to every TV in my Home about 4.5 Years ago - and nothing has been built in the surrounding area - also there is no Tree growth that has become in `line of sight` between the Crystal Palace transmitter and my Home.

The ONLY change is that the Freeview / Digital TV reception has diminished in quality since DAY 2 of the London area Digital TV Switchover !



Thanks again for your interest and very informative messages Mike - I may not go to the extent of erecting the 2 Aerials configuration that I think I understand You were suggesting [?] - but Thanks for the suggestion.


Regards,


Chris

 

[mhar]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

Fair enough. If you are just looking to understand your problem there are two circumstances that are likely to be the cause 1) tuner overload and 2) A decrease in carrier level or an increase in noise level, either resulting in a poor carrier to noise ratio, the tuner then being unable to process the signal.
Unfortunately you have no idea of the signal levels being received or of their quality. Whilst aligning using a cheap meter may give the desired results in most circumstances, it does not distinguish between good noise (carrier) and bad noise or give any useful information.
The solution. Gather the required information then make an educated decision based on fact. My feeling is that it is likely to be down to aerial choice, not necessarily the amount of carrier signal being received but more the amount of unwanted noise being received. If everything downstream of the aerial is 100% as you state it is, then I would be extremely surprised if a professional with a good understanding of the many different bits of information available from a decent meter would not recommend a different aerial. This is not someone charging you £100s for a digital aerial but someone working out which would be the best aerial for your specific location. A very important part of aerial design is what it rejects as well as what it receives. All manufacturers have diagrams available of their aerial's side lobes which can be massively different between models. An understanding of the problem and then the ability to choose the most suitable aerial is what you are paying for.
You are faced with a situation which you are understandably miffed with but which cannot be solved on a forum. My guess is you are receiving an increase in reflected signals during wet weather. I received this email yesterday from Rover (a meter manufacturer) http://www.roverinstruments.com/upl...2013/ROVER_HD_TAB_7_STC_Editorial_2013_EN.pdf Apart from the lte interference graphic I have linked to it so that you can see the many different aspects that need to be considered when an installation is not straightforward.
Without getting professional help, the only thing that I think you are able to do is to combine two of your aerials to make an array. Done properly this will drastically reduce noise and could point you in the right direction.

 

[mhar]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

A little off topic , but not that far !?
I was told by one of our blokes that he recons he had read somewhere that the standard mobile phone reception in the UK is being sacrificed to give more power to the new 4G network .
Now I do not know if this is just one of those scare stories , but I have noticed a distinct lack of reception lately on the O2 network in all sorts of new places across the country !?

Have others heard of , or noticed this as well ?

I gather that there is a bit of 'rationalisation' going on with more sharing of masts. This leads to some masts being deemed redundant by some operators resulting in reception issues. Their response to complaints is basically 'tough'.

 

[chris murphy]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

Fair enough. If you are just looking to understand your problem there are two circumstances that are likely to be the cause 1) tuner overload and 2) A decrease in carrier level or an increase in noise level, either resulting in a poor carrier to noise ratio, the tuner then being unable to process the signal.
Unfortunately you have no idea of the signal levels being received or of their quality. Whilst aligning using a cheap meter may give the desired results in most circumstances, it does not distinguish between good noise (carrier) and bad noise or give any useful information.
The solution. Gather the required information then make an educated decision based on fact. My feeling is that it is likely to be down to aerial choice, not necessarily the amount of carrier signal being received but more the amount of unwanted noise being received. If everything downstream of the aerial is 100% as you state it is, then I would be extremely surprised if a professional with a good understanding of the many different bits of information available from a decent meter would not recommend a different aerial. This is not someone charging you £100s for a digital aerial but someone working out which would be the best aerial for your specific location. A very important part of aerial design is what it rejects as well as what it receives. All manufacturers have diagrams available of their aerial's side lobes which can be massively different between models. An understanding of the problem and then the ability to choose the most suitable aerial is what you are paying for.
You are faced with a situation which you are understandably miffed with but which cannot be solved on a forum. My guess is you are receiving an increase in reflected signals during wet weather. I received this email yesterday from Rover (a meter manufacturer) http://www.roverinstruments.com/upl...2013/ROVER_HD_TAB_7_STC_Editorial_2013_EN.pdf Apart from the lte interference graphic I have linked to it so that you can see the many different aspects that need to be considered when an installation is not straightforward.
Without getting professional help, the only thing that I think you are able to do is to combine two of your aerials to make an array. Done properly this will drastically reduce noise and could point you in the right direction.

"Hello again Mike",


The last thing I want to do is irritate You by repeating my main irritation about this:

My original Post on this matter was soon after the problem started on Day 2 of the London Digital TV Switchover - [there was some `interference` on Day 1] - I had wanted to try and find out why I had what I would class as perfect Freeview reception on every TV in my Home for 3 Years UNTIL the London area Digital TV Switchover ?


The possibility of the New Digital TV signal from the Crystal Palace transmitter having been vastly increased in strength came up straight away - and I had also read in an online article prior to posting on here that the transmitter signal strength had increased X 20 [?].


Then the possibility of using attenuators was suggested by a very helpful Member - I purchased some to try with no noticeable result - it was then suggested that perhaps the inexpensive attenuators even when I connected 2 to the Aerial cable in series were not reducing the signal strength enough.


Because my Neighbours were not having anything like as bad reception problems - even those who had indoor aerials on TV`s in their Bedrooms I thought that this was pointing to the possibility that after the Crystal Palace transmitter signal strength was increased at the Digital Switchover point now my `Good Quality` - Group A - non high gain - Aerials and `Double insulated` / 100 specification Aerial cables were receiving TOO MUCH signal strength and that this was compromising the Signal quality.


I then tried a couple of `Good Quality` Indoor Aerials - One which had an attenuator and one without - these did provide a reasonable Freeview TV reception but there was still interference during rainfall.

I even tried a length of copper wire as an Aerial - a single core from a 2.5 T&E cable - this was suggested to Me by a very knowledgeable TV and Satellite Expert to proove that the Crystal Palace transmitter signal was so strong that ANY Aerial would give Freeview / Digital TV reception where I live.


We did leave the Indoor Aerials in place for a couple of Weeks to observe the Freeview TV reception during various weather conditions - but there was not any improvement over the Roof Aerials so rather than have the Indoor Aerials looking a bit unsightly We went back to the Roof Aerials.


That left Me in the same position as I started in - wondering why after 3 Years of having excellent Freeview TV reception the London area Digital TV Switchover basically ruined it - ?

I would accept the fact that the transmitter signal strength having been increased to help Homes further away from it has compromised My Home`s TV reception if I could have attenuated the Aerials enough to reduce the signal to My TV`s and get back to the strength and quality that I had before the Digital TV Switchover - but I have not been able to either find out if this is possible OR if there are attenuators available which would be able to lower the signal strength enough - without costing a lot of money per TV - ?

IF my Roof Aerials installation had coincided with the Digital TV Switchover I could obviously accept that something needs to be altered / realigned / professionally tested - BUT I had excellent Freeview TV reception for the previous 3 YEARS !


I wrote this before looking at the information on the webpage that You very kindly provided the link to ["Thanks"] - but I will look at that tomorrow when I have a bit more time - and I will definitely look into your suggestion about combining 2 Roof Aerials into an Array - although there is not really a good position for this on my Roof regarding getting the Aerial cable to each of the TV`s - this is why I have 3 Aerials at present.



Thank You very much for your help and advice Mike I really appreciate it.


Regards,


Chris

 

[mhar]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

"Hello again Mike",


I would accept the fact that the transmitter signal strength having been increased to help Homes further away from it has compromised My Home`s TV reception if I could have attenuated the Aerials enough to reduce the signal to My TV`s and get back to the strength and quality that I had before the Digital TV Switchover - but I have not been able to either find out if this is possible OR if there are attenuators available which would be able to lower the signal strength enough - without costing a lot of money per TV - ?

This is exactly what I am suggesting a professional will do. By selecting an aerial most suitable for the location you are attenuating the bad but not affecting the good.
2.5mm t&e as an aerial does open up other possibilities. Are your downleads terminated into a wallplate? Have you used screened coax plugs? Any fly leads not made from ct100)? Either would be a weakness. I have cured a few problems of pre imaging (in the analogue days but have not experienced it being a problem since switchover) where a signal is being collected after the aerial through the cable or even by the tv chassis. Screening is the only answer.
Whichever is the cause I am as convinced as I can be that you are now picking up high powered reflections, maybe not at the aerial, maybe not just at the aerial. This has to be approached logically and requires knowledge of what the problem is and where in the system it is occuring
which can only be ascertained with the use of a decent meter.
The fact that you had perfect reception is irrelevant to what is happening now, bit like going to a central heating problem and the customer saying it was working fine yesterday. The cause is that something has changed. I think that the increase in power has made previously untroublesome reflections a real issue with the rain or snow increasing the reflective properties of whatever is causing the reflection(s).
One simple thing that you could try (without the aid of the professional!!!) is to set an aerial off the horizontal plane, elevate the tip a bit, 15-20 degrees or so or maybe even a little bit more as you have such strong signal. Most aerials can be adjusted in this manner without affecting alignment. Compare this to the other unaltered aerials in wet weather, it may help.
Mike

 

[mhar]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

This will attenuate your signal (at maximum) by roughly the same amount as the increase in transmitter power at switchover TV Aerial Attenuator Variable 0-20Db Freeview Digital | eBay . Maybe try it on your elevated aerial combined with getting rid of your wallplate and using ct100 all the way to the tv with a screened co-ax plug? Let us know

 

[chris murphy]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

This is exactly what I am suggesting a professional will do. By selecting an aerial most suitable for the location you are attenuating the bad but not affecting the good.
2.5mm t&e as an aerial does open up other possibilities. Are your downleads terminated into a wallplate? Have you used screened coax plugs? Any fly leads not made from ct100)? Either would be a weakness. I have cured a few problems of pre imaging (in the analogue days but have not experienced it being a problem since switchover) where a signal is being collected after the aerial through the cable or even by the tv chassis. Screening is the only answer.
Whichever is the cause I am as convinced as I can be that you are now picking up high powered reflections, maybe not at the aerial, maybe not just at the aerial. This has to be approached logically and requires knowledge of what the problem is and where in the system it is occuring
which can only be ascertained with the use of a decent meter.
The fact that you had perfect reception is irrelevant to what is happening now, bit like going to a central heating problem and the customer saying it was working fine yesterday. The cause is that something has changed. I think that the increase in power has made previously untroublesome reflections a real issue with the rain or snow increasing the reflective properties of whatever is causing the reflection(s).
One simple thing that you could try (without the aid of the professional!!!) is to set an aerial off the horizontal plane, elevate the tip a bit, 15-20 degrees or so or maybe even a little bit more as you have such strong signal. Most aerials can be adjusted in this manner without affecting alignment. Compare this to the other unaltered aerials in wet weather, it may help.
Mike

"Hello Mike",

Thanks for the further information and advice.

However I cannot really agree with your analogy about a Central Heating system fault - something would have malfunctioned or possibly air locked / blocked up to cause the fault - which I would be able to find.

Nothing has changed / malfunctioned on my Home`s TV receiving systems / equipment - the ONLY thing that has changed is the Freeview / Digital TV transmission signal !

I do of course agree with You that something is causing my Freeview reception problems - as I mentioned previously there have been no Buildings erected nearby - no extra Tree growth in line with the Aerials - not even any different Roofing materials fitted to any nearby Roofs.

When I keep mentioning that the Freeview reception was excellent prior to the London area Digital TV Switchover and that nothing about my Home`s Aerials or the surrounding area has changed it is because the reception problem started as if a Switch had been turned On which messed up the reception - which I suppose loosely described did happen with the Digital TV Switchover.

I am NOT doubting anything that you have suggested Mike although I am surprised that 3 different Aerials could all be affected by Reflection - these 3 Aerials are quite a long distance apart physically - although I expect that you might say that this would mean nothing in terms of Reflection interference ?

I kept thinking of Years gone by when I had a TV which had only an Indoor Aerial - turning it even slightly would often improve the reception - I did try having the Roof Aerials turned around slightly in each direction when the Freeview reception problems started - we had to return them to their original positions - but We did not think to Tilt the Aerials at all.

The Aerial cables are run in CT 100 specification Double Insulated Co-Axial cable - all the way from the Aerial to the TV`s / Freeview Boxes - there are no wallplates - where there are Fly leads from a Freeview box to the TV these are also made up from CT 100 Co-Axial cable [I did not use the leads supplied with the Freeview boxes] - I am fairly sure that the Co-Axial Plugs are screened and amongst the best quality that you can buy - because I was advised on what to purchase at the time by an Electronics Engineer and I remember the Cable and the co-ax plugs being `reassuringly expensive`.


Regarding the attenuators - the ones that I have are 0 - 20Db - when adjusting one down seemed to be doing nothing I then connected 2 in series to the Aerial cables using small fly leads made up with CT 100 cable and good quality F plugs and a couple of F plug to Co-Ax adapters - having adjusted both down I could still see no difference when I was looking at the Signal strength and Signal Quality displays on the Freeview boxes that I have connected to 2 of the older Bedroom TV`s.

Because my Home`s Aerials and Aerial cables were all in good condition [only 3 Years old at the time] and the Aerials had not moved out of alignment - and there was nothing wrong with any of the TV`s or Freeview boxes - it had to be the NEW Transmitter Signal as far as I was concerned !

BUT the new Digital Switchover was supposed to improve the TV reception !



When there is some suitable weather - [if I still have a Roof after Sunday night / Monday !] I will call on some Friends who are Roofers to help Me to do what You suggested regarding elevating one of the Aerials - I will look at about 20 degrees first and also try 25 degrees - If this does not immediately affect the reception in an adverse way I will leave it like that for a couple of Weeks - I know that We will be getting at least some Rain in November / December - if not some Snow which I read recently will be coming in late November.


If this does not indicate that these adjustments are enabling the Aerial to receive a better quality signal / TV reception I will seriously think about configuring and erecting the Array of 2 Aerials that You suggested - although that would not be until next Spring at the earliest.


By the way Mike I am not averse to using the services of a Professional - as I would be extolling the benefits of people using a Professional Heating Engineer like myself it would be very hypocritical of Me to then NOT want to use other Professionals - but from what I have heard / read / seen on TV documentaries the Aerial Installation Industry has been tarnished with a very bad reputation by the `Rip Off Merchants` / Cowboys.

Of course My Industries of Heating - Plumbing and Gas also sufferers widely from the Cowboys and is notorious for the Rip Off Merchants - but this only makes Me more wary of getting a Cowboy in ALL other Industries !


Thanks very much for all of the time that You have taken to inform and advise Me on this Mike - I really appreciate it.


Regards,

Chris

P.S. I hope that You don`t get any damage to your Home or property from the `Super Storm` that is coming our way on Sunday night / Monday.

 

[mhar]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

Tilting the aerials is the advice we were first given as digital was starting. The idea was to lessen the background noise received from buildings / hillsides etc and also to lessen impulse noise from vehicle electrical systems /lawnmowers etc. If you are able to receive off a bit of t&e inside, tilting your aerial should have no adverse effect at all.
Pockets of interference are not at all unusual, in fact some of us are grateful as that is where we can make our money over window cleaners turned aerial installers!
Can you bring one of these aerials inside the roofspace where it could be less prone to external influences? Have you any foil backed insulation near the aerials? Could you try one of these V20A2 - VISION - AERIAL LOG PREIODIC GROUP A | CPC in your roofspace (tilted, and then maybe coupled to your attenuators)? As a side issue I use Maplins as a showroom and then order from cpc! Most importantly, could you borrow a meter with measurement functions?
I think you may need to look at this from a different perspective. Don't get hung up on signal strength displays, it is the quality you are concerned with. However I am staggered that with 40dB of attenuation these do not change. Do your tv's work (or attempt to work) with the aerial unplugged (in good weather)? Do they work if the aerial is disconnected outside leaving just the downlead acting as an aerial? Could you try a length (3-10'ish) of ct100 with a co-ax plug on one end connected to the tv and see if you get reception, if you don't then pass it out of a window to try?
We should be ok with the storm if it follows predictions, SW veering WNW. If it veers to NW we are pretty vulnerable but as we are on neap tides even this shouldn't be too bad. My youngest, a Western Power linesman, is looking forward to it - Sunday storms are double time storms and he gets paid for sleeping the next day if out all night!

 

[chris murphy]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

Tilting the aerials is the advice we were first given as digital was starting. The idea was to lessen the background noise received from buildings / hillsides etc and also to lessen impulse noise from vehicle electrical systems /lawnmowers etc. If you are able to receive off a bit of t&e inside, tilting your aerial should have no adverse effect at all.
Pockets of interference are not at all unusual, in fact some of us are grateful as that is where we can make our money over window cleaners turned aerial installers!
Can you bring one of these aerials inside the roofspace where it could be less prone to external influences? Have you any foil backed insulation near the aerials? Could you try one of these V20A2 - VISION - AERIAL LOG PREIODIC GROUP A | CPC in your roofspace (tilted, and then maybe coupled to your attenuators)? As a side issue I use Maplins as a showroom and then order from cpc! Most importantly, could you borrow a meter with measurement functions?
I think you may need to look at this from a different perspective. Don't get hung up on signal strength displays, it is the quality you are concerned with. However I am staggered that with 40dB of attenuation these do not change. Do your tv's work (or attempt to work) with the aerial unplugged (in good weather)? Do they work if the aerial is disconnected outside leaving just the downlead acting as an aerial? Could you try a length (3-10'ish) of ct100 with a co-ax plug on one end connected to the tv and see if you get reception, if you don't then pass it out of a window to try?
We should be ok with the storm if it follows predictions, SW veering WNW. If it veers to NW we are pretty vulnerable but as we are on neap tides even this shouldn't be too bad. My youngest, a Western Power linesman, is looking forward to it - Sunday storms are double time storms and he gets paid for sleeping the next day if out all night!

"Hello again Mike",

Thanks again for taking the time to give Me some further information and suggestions.

With regard to trying a length of CT 100 Aerial cable as an Aerial I have done this in the past.

This was a suggestion from the Electronics Engineer who then went on to suggest that I try a length of insulated Electrical wire - I then stripped out about a 2 Metre length of one core from a 2.5 T&E cable.

The length of CT 100 cable worked just as well indoors and out of the windows as the the Roof Aerials - the 2.5 single core Electrical wire also worked just as well indoors as the Roof Aerials - various Indoor Aerials worked just as well as the Roof Aerials - But the TV`s would not show a picture without anything plugged into the Aerial sockets.

I am sure that the Roof Aerial cables would pick up a signal for the TV`s if disconnected from the Aerials - but would still be getting the interference - I am guessing that this would still happen because the interference still happens during Rainfall / bad weather with even an Indoor Aerial.

I had previously wondered whether there could be the situation where the Roof Aerials were getting interference from somewhere - irrespective of the strong transmitter signal - But that the Indoor Aerials were not picking up a strong enough signal during Rainfall / bad Weather and that the TV reception was breaking up because of that - possibly 2 different causes regarding the Roof Aerials versus the Indoor Aerials ?

When I found out that some of My Neighbours were getting good Freeview / Digital TV reception using inexpensive Indoor Aerials I tried using some similar Indoor Aerials - but I still got the disrupted signals during Rainfall / bad Weather.

One of My Neighbours has an Amplified Indoor Aerial which He bought from Argos about 3 Years ago - thinking that He would possibly need an Amplified signal after the Digital TV Switchover - this Aerial gives excellent reception only when the Amplification [Attenuator ?] is turned down so that the indicator light goes Off - even the slightest movement of the dial / Amplification causes the TV`s reception to go completely - obviously this is because the Crystal Palace Transmitter signal is so strong that ANY Amplification causes the signal to be too strong for the TV`s tuner [Guess].

Although it is now not needed He cannot have a Roof Aerial because He has a Roof where replacement [100 Year old half round clay] Tiles cannot be obtained He cannot take the risk of having a Roof Aerial installed - even with Roof ladders there is obviously the chance that a Tile will be broken.


Regarding your comment about the Signal strength indicators on the Freeview boxes - I did mention in My previous message that the attenuators did not seem to be doing anything when I was looking at the Signal strength and Signal Quality indicators.


I think that I am correct in thinking that sometimes in a High Signal strength area lowering the Signal strength can raise the Signal Quality ? I thought that this would be why I would be trying to use the attenuators ?


Thanks for suggesting trying an Aerial in a Roof space and also trying this with the attenuators connected to the Aerial cable - I can do this for the main House Roof space where there is access into the Loft - I will buy one of the Group A Aerials that You very kindly mentioned and make up a long Aerial cable using the CT 100 Aerial cable and good / screened Co-Ax Plugs.

I will try it in the Horizontal position - various Tilted positions around the 15 to 25 % Tilts that You mentioned - and with the attenuators.

However this is something that I cannot do without some preperation as I have a completely Insulated Roof space - to a depth of about 500mm of Insulation - cross layed above the Ceiling Joists - as You know it is extremely dangerous to try moving about in such a Roof space without at least making some form of temporary platform - I really would have to lift up all of the Insulation above the Ceiling Joists to be able to walk across them to where I needed to mount the Loft Aerial and then relay the Insulation.


JUST A NOTE FOR OTHER READERS OF THIS REGARDING LAYING BOARDS ACROSS LOFT INSULATION TO ACCESS AN INSULATED ROOF SPACE:

It is always a mistake to put Boards across thick layers of Loft Insulation - the Insulating properties of the Insulation relies to a great extent on the Thickness / Air content of the Insulation - squashing it down obviously lessens the Air content and alters the density - rendering the Insulation value much less than the original thickness was - it is NOT usually successful to `Plump Up` Loft Insulation to its original density / air content after having boards laid across it.

As I would need to tempoarily have the Aerial cable hanging out of the Loft hatch with it wedged slightly open this might not be the best time of Year to try this - I am sure that You will know at how much Heat from a Home would escape through even just something like a 12mm x 600mm gap into a cold Roof space.

Unfortunately for the purpose of installing a Loft Aerial on a permanent basis My Home`s Loft hatch is a long distance from where I could mount the Loft Aerial and even further from where the Aerial cable would have to exit the Loft to be adjacent to the Main Bedroom - I would have to lift / roll up a lot of Insulation from one end of the Loft to the other - quite a Job - then I would have to take up quite a lot of Floorboards / Drill Joists etc. in a Hallway and the Main Bedroom - moving almost everything in the Bedroom to get the Aerial cable to the TV - quite a lot of disruption.


I am NOT trying to `find obstacles` to following your excellent advice Mike - I just wanted to explain why the Loft Aerial trial will not be something that I can comtemplate doing in the immediate future - But I will try it as it would be good to be able to solve the disrupted reception problem during Rainfall / bad Weather for at least my Main Bedroom TV - which is where I watch most of the TV that I view anyway.

I will find this thread again probably in the Spring of next Year when lifting up the Roof Insulation would be more appropriate and I will post My `Findings` to your Loft Aerial suggestion / the `Tests` with the Tilting and attenuators then.

Please don`t be frustrated that I don`t follow your suggestions immediately Mike - I know that it might seem like I am not interested in `Fixing` the Reception / Interference problems which will obviously be even more frequent in Autumn and Winter time.


But You will see from the Date of the original thread I have had to live with this problem fror quite a long time now and I have to weigh up the disruption to the TV reception with the disruption to the Loft Insulation / Heat loss through the wedged open Loft hatch [for a couple of Weeks] - temporary Aerial cable trailing through the House etc



Thanks again for your Help - the detailed Information and excellent advice Mike - I really appreciate being able to correspond with an Expert like You regarding the Reception problems on My TV`s / Aerials.


I was glad to read that your Home / Area was not likely to be badly affected by the Forcasted High Winds / Heavy Rainfall combination.


Where I live in London We had nothing like the High Winds that I was expecting - I can remember many ocassions where the Winds have been much stronger - but obviously I am glad that this was the case.



Regards,

Chris

 

[mhar]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

The aerial receives a signal traveling from the transmitter at the speed of light. Once collected the signal is slowed by having to travel down the cable (it is no longer traveling through free air), however the cable is picking up signal that is traveling through free air and this unwanted signal is arriving at the tuner before the wanted signal. In the analogue days this was pre-imaging, the opposite of ghosting which is time delayed images. It could very easily be the case that with the increased power and with the reflective effect during rain / snow that the cable is picking up multiple (reflected) signals that are now sufficient to drown out the wanted signal as far as the tuner is concerned. One signal (interference) measurement at the aerial (during rain) followed by one at the tv would confirm this and may well point you in the right direction. The answer would be to alter the cable route to achieve screening by your building, use triple screened cable (relatively new) or screen the existing route.
If the problem is downstream of the aerial then alterations to the aerial will have no or little effect. Of course it could be a combination of a number of problems. With a decent meter such problems can be identified relatively easily.
Have sent a pm

 

[mhar]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

Should have said that it is also quite possible that the tv chassis itself is receiving this interference and would require screening.
Lowering signal levels in high strength areas would not improve quality, however it may make the difference between presenting too high a level of signal to the tuner to presenting a level that the tuner can better work with.
I am far from an expert, just old and have encountered a few things in my time and I like to try to understand what I am dealing with!
Slept right through the storm! Weather data showed us getting away very lightly but only a few miles away people really suffered - my youngest spent all day in Exeter as they had many people off supply, only 40 miles or so away.

 

[chris murphy]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

The aerial receives a signal traveling from the transmitter at the speed of light. Once collected the signal is slowed by having to travel down the cable (it is no longer traveling through free air), however the cable is picking up signal that is traveling through free air and this unwanted signal is arriving at the tuner before the wanted signal. In the analogue days this was pre-imaging, the opposite of ghosting which is time delayed images. It could very easily be the case that with the increased power and with the reflective effect during rain / snow that the cable is picking up multiple (reflected) signals that are now sufficient to drown out the wanted signal as far as the tuner is concerned. One signal (interference) measurement at the aerial (during rain) followed by one at the tv would confirm this and may well point you in the right direction. The answer would be to alter the cable route to achieve screening by your building, use triple screened cable (relatively new) or screen the existing route.
If the problem is downstream of the aerial then alterations to the aerial will have no or little effect. Of course it could be a combination of a number of problems. With a decent meter such problems can be identified relatively easily.
Have sent a pm

"Hello Mike",


Thanks very much for your reply and for your PM.


As if I did not have enough problems with the Freeview / Digital TV - Now I am getting really bad `interference` on MOST of my Home`s TV`s - which I THINK is coming from the 4G Mobile phone network.

I think that it is from 4G because when I plug in one of the 4G Filters that I purchased in advance of this possibly happening it stops the `interference`. I am guessing that there should NOT be any other source of interference that these Filters prevent [?] - as the TV channel `Bands` / Ranges for Digital TV are supposed to be dedicated for only TV - with the exception now of 4G - and the 5G etc. interference that You mentioned in one of your very informative messages to Me - ?


I have noted that this interference seems to `only` affect: ITV1 - CH4 - CH5 - ITV2 - CH4+1 - MORE4 - FILM4 - E4 and ITV1+1 - would I be correct in assuming that these channels are all part of One `Range / Block` of channels on Digital TV ?


I also noted that ITV3 - ITV3+1 - ITV4 - CH5+1 and FILM4+1 were not affected by this interference - But I am guessing that they are on a different `Block` of Channels that are transmitted - ?


This interference causes the affected Channels to become completely unwatchable - total loss of picture or really bad `Blocking` and totally disrupted Sound - but this is NOT happening on every TV / Freeview Box in the House - there is ONE TV where the reception is not disrupted - although the channels that I mention below are disrupted on a Freeview DVR that is connected to that TV and to the same Aerial !

Before I tried fitting the 4G Filter to my Bedroom TV`s Aerial cable / TV Co-Ax connection I went into the Self Diagnosis menu on my TV - under Signal Information I saw that the Signal Strength on the affected channels had reduced to between 30 and 40 out of 100 [Max.] - usually at least 85+ - BUT that there was a `Bit Error` display scale - this was showing 9 to 10 out of 10 in RED ! - this is obviously very significant regarding the Signal that was being received by these disrupted channels although I did not get an explanation from the TV Manufacturer Technical Support on what exactly this `Bit Error` meant.


I tried speaking to the TV Manufacturers Technical Helpline although I was fairly sure that this was an external problem I wanted to discuss this with them just in case - at that time I had [stupidly] only checked the Living Room TV Freeview reception - not the other Bedroom TV`s / Freeview boxes - the Living Room TV was O.K. - so I thought it MIGHT have been a problem with the Bedroom TV at that point.

They suggested trying an Automatic Retune - I stated that I thought that this would not `find` the Channels that were being severely disrupted - I was correct - all of the Channels that had bad interference were `Gone`!


I managed to put them back into their locations onto the TV by running a CT 100 extension lead from the Bedroom TV to the Aerial cable on the Living Room TV and the doing an Automatic Retune on the Bedroom TV - but the channels that I identified above were still severely disrupted.


I then tried fitting one of the 4G Filters which immediately removed this recent interference.


I then checked my other TV`s - with the exception of the Living Room TV these were also badly disrupted by the interference - I tried the 4G Filter in each case - it stopped the interference to the Freeview boxes / TV`s.

I then found that although there was no interference on the Living Room TV there was bad interference on the Freeview DVR that is connected to it / the same Aerial ! - a 4G Filter would NOT stop this on the DVR - obviously I am surprised about that as they seem to have worked on every other Freeview box / TV.


I have been experiencing the other interference to my Home`s TV`s since well before any possibility of 4G interference so I know that it is not related to the present Signal disruption and that it is unlikely that these 4G Filters will improve the situation of disruption during Rainfall / Snow etc.

I cannot wait to see if there is even MORE interference to my Home`s TV`s during Rainfall / Snow etc. - possibly exacerbated by the new 4G Network interference IF there is any `Bypassing` of the 4G Filters as well as the existing interference problems - ?

Anyway I thought that I would tell You about the latest `Fun` that I have been having trying to just get back to the Great TV reception on Freeview / Digital TV that We enjoyed for about 3 Years prior to the London Area Digital TV Switchover ! [Sorry for mentioning that again]



Thanks again for all of your Help - Information and Advice Mike - I really appreciate it.


Regards,


Chris

 

[chris murphy]

Re: 4g mobile phone network rumoured very likely to severely affect freeview tv rece

"Hello All",

I am afraid that I spoke / wrote too soon when I stated that the 4G Filters stopped the interference that I thought was from the new 4G Mobile phone Network transmissions / Mast Transmissions [?].

Tonight at about 18:30 Hours [6:30pm] I saw that my Bedroom TV Freeview / Digital TV reception was badly disrupted again - this seemed to be in `Bursts` / brief periods of time and the interference totally disrupts the Screen / Picture and Sound - it is sometimes disrupting the picture so badly that the Colours merge into what looks like a Modern Art `Blur of Colour` - [a `Blur` is what it is].

This happened three more times between then and 21:00 Hours [9pm] - as I have only 2 of the 4G Filters I could only check my Bedroom TV where I did not want to keep unplugging the Filter and use the other Filter to check 2 other Freeview boxes / TV`s - when the disruption was happening it happened on all 3 of these TV`s / Freeview boxes.

As I mentioned in my previous message the Living Room TV was not affected by this interference - I did not have time to check the Freeview DVR which is connected to that TV.

This seems to be so intermittent that I cannot imagine ever being able to arrange to get the Signal Tested professionally at the exact time when this occurs again in the future - I had a Family member checking the previously affected Channels all during Today while they were at Home watching TV - there was no disruption / interference during the Daytime today.


I will obviously check whether there does seem to be any pattern / repetition at certain times - perhaps in the early Evening as happened Tonight.

If I remove the 4G Filters the channels that I listed above which were severely disrupted have no reception at all - so the Filters are achieving something - but seem to be being `overwhelmed` by some type of interference at times.


I really cannot believe My `Bad Luck` regarding the Freeview / Digital TV reception / interference on my TV`s !

It seems something has not only changed on Day 2 of the London area Digital TV Switchover [coincidence ?] lin April 2012 which ruins the Freeview reception on my Home`s TV`s during Rainfall / Snow - BUT - NOW I have severe Signal disruption intermittently - which I thought was being caused by the new 4G Mobile phone Network transmissions [newly commissioned 4G mast ?] - IF this IS the case the 4G Filters that I mentioned having purchased in advance of the possibility of a 4G Network problem have not worked 100%.


I wanted to `Update` my earlier comment that the 4G Filters had immediately removed the interference - they did when I plugged them into the Aerial / TV Co-Ax socket - but later Today / this Evening the disrupted Signal started happening again in `Bursts` / short periods.

I realise that these 4G Filters probably work perfectly to Filter out the 4G Network transmissions - I wonder if I am experiencing some other type of TV Signal disruption ?

Obviously I know that this cannot be answered on any Forum - Professional Tests will have to be carried out - BUT - I obviously cannot know when this interference will exhibit again !


I will be trying to monitor the situation on my TV`s - slightly awkward without a 4G Filter for each TV / Freeview box - but I don`t really want to be buying 3 more at £14.99 each [there are £7.99 ones available at Maplin] only to find out that it is NOT the 4G Network transmissions causing the problems and be left with about £65.00 worth of 4G Filters that I may NEVER need [?].


Regards,

Chris