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