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Interference between DTT & Mobile services in the UHF bands

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  • 13-01-2012 3:35am
    #1
    The Cush
    Registered Users Posts: 15,522 ✭✭✭✭


    How will viewers with Group C/D and Wideband aerials (and masthead amps) be effected by the launch of mobile services above Ch 60?

    This appears to be of concern to RTÉ/RTÉNL and not to the Dept or Comreg as can be seen from a series of emails between then in the last few months, published recently by Comreg.

    RTÉNL says it's a policy issue for Comreg but Comreg says any interference problems are a technical issue for RTÉNL/installers/viewers to resolve.

    RTÉNL's Mick Kehoe said the following in an email
    RTÉNL stand by its position and at least if/when a problem does arise we will know where to divert the phone calls.


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    #2
    watty
    Registered Users Posts: 32,417 ✭✭✭✭watty


    UPC cable will be affected even worse. Tests have proved loss of Broadband and TV when the Mobile Handset is used in the same house.

    The so called "digital dividend" is stupidity. The spectrum being offered isn't suitable for 4G Mobile Data at decent speed as the size is too small, Comreg wants 5MHz channels and 4 operators and the range is too great to have smaller cells reliably to increase capacity.

    The whole "Digital Dividend" concept was when DTT was imagined to be SD only. No HD or 3D, and also no Satellite or Cable competition.

    You can use the 790MHz to 862MHz band for FIXED wireless, as then there are no omni-directional handsets or USB dongles, just an aerial on roof with wireless set feeding a cable modem. The equipment exists off the shelf and is used in several countries. But the Licence process is loaded against such a system. The Fixed Wireless would not interfere with TV or Cable.

    The 1800MHz band is badly used.
    The 2300MHz band is hardly used.
    Big chunks of 872MHz to 1000MHz (containing GSM) are wasted.

    The Digital Dividend is 2nd stupid thing since Broadcasting started in 1921, and the 2nd stupidest so far.

    So called "White Space", reusing the in Use TV band channels for license-free "outdoor wifi" is the 3rd stupid idea since 1921. It wins the award of being the most stupid and will create FAR more interference than Mobile in the "Digital Dividend" band as the Database scheme can't work reliably.

    We are entering an era where Broadcast is no longer protected. Even though the Broadcasters have a licence and the frequencies protected by International Treaty.

    The only "right" people have for mains wiring is to get Electricity from it. But Ethernet over Mains and HDMI over Mains are really transmitters now creating interference from 1MHz to 200MHz. Each new generation of "Homeplug" type gadget goes faster and blocks more frequencies.

    CE marks are not enforced or policed or properly independently verified so we have PSUs, CFL, chargers etc with filters left out to save cost which make Radio reception from 60Khz up to 20MHz or even weaker VHF-FM stations unusuable.


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    #3
    Sponge Bob
    Banned (with Prison Access) Posts: 25,234 ✭✭✭✭Sponge Bob


    The reason this is of concern is that I understand the interference has started already.

    Some high end multiband US LTE Phones have already appeared in Ireland hooting away between 700 and 800mhz and the situation will likely continue to worsen.

    Interference with masthead amps can be caused by crap masthead amps, eg wideband ones. I blame the installers for a lot of these, and the same problem was around for some time after Tetra was launched down the bottom end of the UHF band.

    Even ole Sponge Bob himself is possibly guilty, must check these in case I nuke a Radio Mike. :)


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    #4
    Mike 1972
    Closed Accounts Posts: 8,018 ✭✭✭Mike 1972


    I never thought Id ever hear myself utter these words but......

    Surely COMREG are right on this one :eek:

    After ASO frequenciess above Ch 60 will be out of band and masthead amps without filtering for these out of band frequencies will be obsolete ?

    Its hardly reasonable for broadcasters (and ESPECIALLY cable companies) to demand protection from out of band signals on obsolete or substandard recieving equipment ?
    watty wrote: »
    since Broadcasting started in 1921..
    1921 ???
    watty wrote: »
    We are entering an era where Broadcast is no longer protected. Even though the Broadcasters have a licence and the frequencies protected by International Treaty..

    We have been in that era for quite some time now In most countries AM radio broadcasting has been unprotected for decades (nope that doesnt mean AM pirates are guranteed a free pass though) Its only a matter of time before the (already largely worthless*) protection is withdrawn from FM with the existance of DAB given as an excuse.

    * Having being involved in an almost three year campaign to get RTE to clean up spurious signals from one of their FM relay sites. I can attest to this.


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    #5
    watty
    Registered Users Posts: 32,417 ✭✭✭✭watty


    Even with really professional filtering and NO mast amp the local handset / Modem dongle is a problem. If there is an attic aerial or indoor aerial the problem is worse.

    If ordinary coax is used to connect the TV rather than Satellite grade with foil screen and heavy braid the problem is worse.

    I'm not going to explain it here. But even when a transmitter ONLY has transmissions in it's own band it only needs to be about 40dB stronger than a nearby channel to start causing interference.


    I said nothing about AM. The fact is that technologies are being allowed that disrupt AM, FM, HF, Mobile, Marine, Aeronautical and HAM. All those are licensed and protected. Any "Amateur" frequencies that are secondary, it's because the PRIMARY licensed user is protected. Besides AM broadcast still does have legal protection in every country by International treaty. Enforcement is a separate issue. Comreg are pathetic at it. They have regularly dragged their feet over Interference issues and also forbidden the victim to say to their customers who the villain was when identified. They are not fit to regulate "White Space" or "Digital Dividend" on their past record of being more interested in collecting Revenue for Dept of Finance. Which is not the stated function of a Communications Regulator. No one ever changed the law or treaties. The problem is Comreg's lack of enforcement. Hence RTE's disquiet about "Digital Dividend". I bet they are in caniptions about "White Space". The problem is Regulators like Ofcom, FCC and Comreg (unilaterally) allowing "Interference", contrary to law.

    Only the ISM / Licence free band users have no protection. (CB, 49MHz, 433MHz, 446MHz, 864MHz, 2.4GHz, 5.8GHz)


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    #6
    NewHillel
    Registered Users Posts: 736 ✭✭✭NewHillel


    Firstly, I agree with the COMREG position.

    However, the correspondence published, shows the value of a professional aerial installation, by competent installers, with the right equipment.

    This is an area where the ISAA could really shine, without any of the 'Rogue Installer' $hite.

    Why not offer real
    consumer protection, in two critical areas:

    1. A financial guarantee on the quality of the installation, to a certain financial limit, say €300. (The CAI already do this,at least in the UK.)

    2. A guarantee that any future interference issues will be resolved, or the installation cost refunded, for a 5 year period.

    These are real differentiators that couldn't easily be matched by untrained or badly equipped installers.

    Think about it, it would provide a real basis for an ISAA campaign, along the lines of 'Why you should choose an ISAA installer. (Put it this way, I wouldn't even bother doing work for myself, as I couldn't be bothered sourcing the necessary filters, etc., required.)

    The ISAA could negotiate suitable insurance cover, for itself and members, to mitigate the financial risk.


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    #7
    Mike 1972
    Closed Accounts Posts: 8,018 ✭✭✭Mike 1972


    watty wrote: »
    I'm not going to explain it here. But even when a transmitter ONLY has transmissions in it's own band it only needs to be about 40dB stronger than a nearby channel to start causing interference.

    Im not suggesting reciever generated interference from out of band transmissions wont be a problem but is it an issue that COMREG should concern theselves with given that the onus in such cases is on the user of the reciever to resolve such issues ? International treaties concern themselves with in band signals and transmitter generated spurious emissions.

    As any RF transmitter can potentially interference on inadequetly designed or screened recieving installations on widely differing frequency ranges any proposal that restrictions be imposed on such transmissions would be patently unworkable besides given that COMREG are unwilling/incapable of resolving most of the in-band interference which arises legislating for out of band issues would be rather pointless.

    Im with you on the PLT/White Space/General EMC stuf though !


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    #8
    watty
    Registered Users Posts: 32,417 ✭✭✭✭watty


    Actually guard bands exist between different type services by International Agreement. These have to take account of:
    • The typical location of Transmitter
    • Type of modulation and level of out of band signal due to that
    • Existing neighbour band equipment.

    Harmonics of transmitters and spurious signals from Transmitter IF and L.O. harmonics on both sides of carrier are not really a problem on Modern systems. The points above are serious issues.

    Even if the Receiver generates NO interference the filters will not block a local transmitter 100dB more than desired RF, only 20MHz away. It's not feasible in consumer gear. Though it's a huge problem for UPC as someone using a Tablet or phone is actually ON the Cable TV digital TV or Modem frequency at 100dB more power than Three Rock at same location. In Sth. Dublin the Analogue, DTT and DAB all interfere with cable to some extent. A nearby "Digital Dividend" Handset/Modem could be over 100dB more. The Masts are a tiny problem in comparison.


    The Guard band size for "Digital Dividend" is designed unfortunately only taking the Base or Mast transmitter into account. It would be fine for Fixed Wireless. However Mobile Handsets and USB dongles and Tablets etc are likely to be used indoors. These are largely the interference problem. Though there are problems with mast Amps or larger aerials in line with a Mobile Mast. Even GSM can be a problem today on higher channels UHF if the TX is far off and a nearby mobile mast. But it's rare. GSM Mast TX frequencies are upward from about 925MHz. Top UHF TV is 862MHz.

    But my argument is deeper. I do not believe this is driven by consumer need, nor required. It's just a way for Mobile operators to build giant cells with x3 fewer to x9 fewer masts (and consequent 1/3rd to 1/9th data cap or user numbers) for Rural locations. It will forever sacrifice TV band in exchange for "Midband" Mobile Data that just saves some Capex to foreign operators. It will not benefit Broadband use or local Wireless ISPs.

    The so called "Digital Dividend" should be scrapped in all of Europe and the space reserved for HDTV, 3D TV, real 3D TV etc... There is plenty of other more suitable Spectrum for Mobile and Fixed Wireless. No shortage if it used efficently.

    The reality is the "Digital Dividend" is not to benefit the Consumer at all, but Government coffers by sell of of spectrum to highest bidders. It's 100% driven by selfish "Depts of Finance", no other reason.

    If they insist on the Stupid "cash grab" of "Digital Dividend" there is a solution. Licence should be for outdoor greater than 9dBd gain fixed aerials at chimney height only, fixed wireless. The contention should be limited to 20:1 by sufficient channels and base stations and the peak time speed no less that 90% of package speed, which should be a minimum of 2Mbps up and 16Mbps down. That would be real Broadband with range up to 40km with suitable aerials. The Technology has existed off the shelf for over 8 years.

    It's Wireless DOSCIS, UPC's Cable Broadband over Wireless. It's what the Digiweb Metro uses (much more expensive band and only Line Of Sight 10km range as it's 10,600MHz not 800MHz).

    Rural LTE or Mobile WiMax on 800MHz with the 4 operators and 5MHz Comreg envisage could actually be poorer than 3G in many locations. To get decent speed the LTE needs a single "RAN" operator in a band and at least 6 x 20MHz channels in both directions (up and down). That would need the Entire existing GSM band, some other bits and a slightly extended "Digital Dividend" band to have 240MHz with duplex guard in the middle and Guard at top and bottom end. The existing Licence Free unprotected 864MHz to 868MHz gadgets, walkie talkies and cordless barcode terminals can live in the duplex guard band.

    But the current proposal essentially tailored to raise maximum revenue from Mobile operators (no way can Fixed Wireless ISPs compete) is a disaster for all of Europe.


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    #9
    Antenna
    Registered Users Posts: 2,313 ✭✭✭Antenna


    watty wrote: »
    In Sth. Dublin the Analogue, DTT and DAB all interfere with cable to some extent.

    There were no problems with DTT affecting cable in Dublin as it is above both analogue and digital cable in frequency there - though it did happen in Waterford city when the new transmitter for DTT there did clash with analogue cable in the low end of the UHF band.
    http://www.boards.ie/vbulletin/showthread.php?t=2055767531
    The solution was for UPC to duplicate the affected on another channel and get viewers to retune. Was big problem due to the close proximity of the transmitter to cabled areas!

    However Dublin has DAB affecting BBC2 TV on UPC analogue cable where areas with a strong DAB signal + cable pickup/ingress a problem, posted here many times in the past.


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    #10
    watty
    Registered Users Posts: 32,417 ✭✭✭✭watty


    It does interfere, reducing SNR on digital carriers used for DOCSIS (Broadband) and Digital TV. But if the interference is below low enough for the FEC and SNR (BER), the user is not affected. LTE will interfere enough to affect it from User perspective.

    Without Spectrum analysers and meters that display BER, it's not possible for users to see serious interference that is just below the threshold.
    Antenna wrote: »
    However Dublin has DAB affecting BBC2 TV on UPC analogue cable where areas with a strong DAB signal + cable pickup/ingress a problem, posted here many times in the past.

    A local "digital dividend" handset / Modem upload channel will be maybe 100dB more than DAB.

    Also it's normal on all Mobile systems and many fixed systems for the uplink (handset/modem) to transmit on the lower half of the band, then an empty duplex guard and then the Mast downlink transmits on top half of band. Unfortunately that is the worst way round for co-existence with DTT or Cable. :(

    An aside
    Digiweb Metro is one the few reverse systems, the downlink is 10.2GHz, uplink 10.6GHz roughly (most systems the uplink is lower band). It's DOCSIS like UPC, DOCSIS can use any channel between 110MHz and 862MHz, or even maybe 1.2GHz (Channels are from 2MHz wide to 10MHz wide, but 6MHz USA and 8MHZ Europe are the common sizes)on some for downlink with the uplink using 0.8, 1.6, 3.2 or 6.4MHz channel between 5MHz and 65MHz. UPC channels between 110MHz and 862MHz are 8MHz and can each be a DVB-C "multiplex", DOCSIS downlink or one Analogue channel. Since the Analogue channels came first they use the lower frequencies as the cable network originally was upto 450MHz, then 560MHz and now 862MHz, or exceptionally in some Countries now 1200MHz (1.2GHz). As cable is converted to HFC with fibre fed cabinets many networks can expand to 1.2GHz to have 100Mbps data at low contention, VOD, Switched video and HDTV.
    So the outdoor Wireless set uses a single L.O. at about 9.7GHz to convert the 10.2GHz to 485MHz approx (in cable modem downlink band) and the Modem 21MHz uplink converted to 821MHz and then same L.O. as for receive added to give the 10.6GHz approx uplink. I suspect the choice of frequencies is to reduce cost. The Metro outdoor unit is 1/6th of cost of previous non-DOCSIS 10GHz links and about 1/5th cost of current alternate 10GHz links. The coax carries +12V power and identical signals as a UPC modem would use.


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    #11
    NewHillel
    Registered Users Posts: 736 ✭✭✭NewHillel


    watty wrote: »
    It does interfere, reducing SNR on digital carriers used for DOCSIS (Broadband) and Digital TV. But if the interference is below low enough for the FEC and SNR (BER), the user is not affected. LTE will interfere enough to affect it from User perspective.

    Without Spectrum analysers and meters that display BER, it's not possible for users to see serious interference that is just below the threshold.

    Hence my suggestion that this is a real opportunity for the ISAA. Surely, one of the means of minimising this concern, and future-proofing installations, is to have adequate shielding with the option of suitable filters, if subsequently required? (I'm not referring to 'cable' installations, here.)

    Only a small number of installers need have a deep understanding of problematic interference identification and mitigation and the more sophisticated equipment needed for same, similar to 2nd level support. This could then be available to all installers.


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    #12
    watty
    Registered Users Posts: 32,417 ✭✭✭✭watty


    NewHillel wrote: »
    Hence my suggestion that this is a real opportunity for the ISAA.
    ....
    small number of installers need have a deep understanding of problematic interference identification and mitigation and the more sophisticated equipment needed for same, similar to 2nd level support. This could then be available to all installers.

    Decent filters that make a difference are very expensive. Also they will only help with interference received by aerial on roof. The major problem with "digital dividend" be local modem dongle/handset getting picked up by TV, Set-box, coax or RF patch cord directly. Nothing can mitigate that.

    ISAA and professional installers have always recommended TX100 / PF100 / CT100 type foil + heavy screen satellite cables, not the cobweb screen stuff installed by most builders and sold in many retail shop. UPC believes in "RG6" but you'll find that professional cable makers make many types/grades of "RG6"-something varying from Aluminium metallised plastic for screen foil, with loose aluminium braid and copper plated steel inner core wire (cheapest and to be avoided) to an "RG6"-something-else with dense copper braid you can't see through, solid copper foil and solid copper inner core wire, with identical spec to PF100. So "RG6" on its own isn't a useful spec.


    Yes, from the beginning I suggested that ISAA set up a technical support panel with gear, and also gear available to hire for those qualified to use it (at a price to cover wear & tear and upgrades). This would be one of the benefits of membership. It was never ever envisaged as a "bulk purchasing club" or "trade cartel" like some groups are (I'm NOT thinking of anyone in particular, OK?).


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    #13
    NewHillel
    Registered Users Posts: 736 ✭✭✭NewHillel


    watty wrote: »
    Decent filters that make a difference are very expensive. Also they will only help with interference received by aerial on roof. The major problem with "digital dividend" be local modem dongle/handset getting picked up by TV, Set-box, coax or RF patch cord directly. Nothing can mitigate that.

    ISAA and professional installers have always recommended TX100 / PF100 / CT100 type foil + heavy screen satellite cables, not the cobweb screen stuff installed by most builders and sold in many retail shop. UPC believes in "RG6" but you'll find that professional cable makers make many types/grades of "RG6"-something varying from Aluminium metallised plastic for screen foil, with loose aluminium braid and copper plated steel inner core wire (cheapest and to be avoided) to an "RG6"-something-else with dense copper braid you can't see through, solid copper foil and solid copper inner core wire, with identical spec to PF100. So "RG6" on its own isn't a useful spec.


    Yes, from the beginning I suggested that ISAA set up a technical support panel with gear, and also gear available to hire for those qualified to use it (at a price to cover wear & tear and upgrades). This would be one of the benefits of membership. It was never ever envisaged as a "bulk purchasing club" or "trade cartel" like some groups are (I'm NOT thinking of anyone in particular, OK?).

    I agree with most of the above, I do believe that a fully shielded termination, all the way to the TV, would mitigate in-Home generated interence, also. With the proposed installation inspections the ISSA should really stand out from the crowd.

    (PS, There is evidence to suggest that Operators are starting to move way from Homeplug solutions, due to interference issues.)


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    #14
    watty
    Registered Users Posts: 32,417 ✭✭✭✭watty


    BT's own DSL people told BT Vision people not to do it, at the beginning! On occasion "Homeplug" blocks DSL or causes it to sync at much much lower speed. I'd guess when there are runs of phone and mains side by side, or outdoor overhead phone cable picking up the lights wiring. Often lights are wired with Live and negative separate cables to loop between fittings, switches etc and thus the lighting circuits make great loop aerials for Homeplug and other high speed signalling over mains solutions.


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    #15
    watty
    Registered Users Posts: 32,417 ✭✭✭✭watty


    NewHillel wrote: »
    I do believe that a fully shielded termination, all the way to the TV, would mitigate in-Home generated interence, also.

    Sadly I have found that it doesn't work as the boxes / TVs are not shielded and also may use unshielded poor design of PC track or such. Also viewers will add a box and use cheap RF patch cable.

    The Belling lee connectors are rubbish design that isn't even 75 Ohms. Proper quality F-Connectors are better. Badly fitted screw on types can be worse.

    I've even seen PC mice affected by 0.5W RF and systems fall over due to RF pickup on the speaker cables.

    It was easier to add a filter on old Record Players to stop them picking up Taxis and Police in the "old days" than sort EMI "retro fit" problems on some modern gear.

    The number of Plug Top PSUs even I've had to scrap as there was no filtering (and yet they had CE marks, no way would they have passed).

    The Regulator is not doing their job. The CE mark system is broken as it's not pro-actively policed or independently verified.

    This the environment Comreg wants to unleash licence Free "White Space" and also Mobile use of the "Digital Dividend" band.

    I'd only just support the "Digital Dividend" if the Regulator showed competence and wrote the licence conditions to limit it only to "Fixed Wireless". It's impossible to mitigate Mobile Interference on such nearby band.

    They want "White Space" in similar time scale. Madness.


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    #16
    NewHillel
    Registered Users Posts: 736 ✭✭✭NewHillel


    watty wrote: »
    Sadly I have found that it doesn't work as the boxes / TVs are not shielded and also may use unshielded poor design of PC track or such. Also viewers will add a box and use cheap RF patch cable.

    The Belling lee connectors are rubbish design that isn't even 75 Ohms. Proper quality F-Connectors are better. Badly fitted screw on types can be worse.

    I agree that the Belling Lee connectors are rubbish, but the ISAA. Could standardise on F Connectors, with a suitable adapter for the TV. The additional cost, when bought in bulk, is not much.

    Crimp F connectors can also be badly fitted, and be equally bad. It really comes down to proper tools, proper materials and training.

    The Conformance Testing is an entirely different matter. I suspect we are close in our thinking.


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    #17
    watty
    Registered Users Posts: 32,417 ✭✭✭✭watty


    NewHillel wrote: »
    I agree that the Belling Lee connectors are rubbish, but the ISAA. Could standardise on F Connectors, with a suitable adapter for the TV. The additional cost, when bought in bulk, is not much.

    I've tried that. Sadly the Belling Lee Socket isn't 75 Ohms either. If you have mis-match even a double screened coax radiates and picks up. On UHF repeaters I've used ferrite clamps + cable loop as UHF balun/current mode choke and third screen earthed only at the radio end to get good isolation. That was on systems with BNCs. With good isolation I was able to get 300m range with the transmitter at 100mW direct into a 50 Ohm BNC dummy load. Normal aerial on the Repeater. Audio on the 8W UHF transmitter and 5W VHF transmitter driven from the UHF receiver. All in one case with a single dual band VHF/UHF aerial. That kind of engineering isn't plausible on domestic systems. I had to UHF filter all the power and audio cables and isolate the metal cases of the three radios from metal chassis!


    I've also tested domestic gear with a screened 75 Ohm dummy load on input and it's amazing how much is still received!


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    #18
    FREETV
    Registered Users Posts: 1,673 ✭✭✭FREETV


    watty wrote: »
    UPC cable will be affected even worse. Tests have proved loss of Broadband and TV when the Mobile Handset is used in the same house.

    The so called "digital dividend" is stupidity. The spectrum being offered isn't suitable for 4G Mobile Data at decent speed as the size is too small, Comreg wants 5MHz channels and 4 operators and the range is too great to have smaller cells reliably to increase capacity.

    The whole "Digital Dividend" concept was when DTT was imagined to be SD only. No HD or 3D, and also no Satellite or Cable competition.

    You can use the 790MHz to 862MHz band for FIXED wireless, as then there are no omni-directional handsets or USB dongles, just an aerial on roof with wireless set feeding a cable modem. The equipment exists off the shelf and is used in several countries. But the Licence process is loaded against such a system. The Fixed Wireless would not interfere with TV or Cable.

    The 1800MHz band is badly used.
    The 2300MHz band is hardly used.
    Big chunks of 872MHz to 1000MHz (containing GSM) are wasted.

    The Digital Dividend is 2nd stupid thing since Broadcasting started in 1921, and the 2nd stupidest so far.

    So called "White Space", reusing the in Use TV band channels for license-free "outdoor wifi" is the 3rd stupid idea since 1921. It wins the award of being the most stupid and will create FAR more interference than Mobile in the "Digital Dividend" band as the Database scheme can't work reliably.

    We are entering an era where Broadcast is no longer protected. Even though the Broadcasters have a licence and the frequencies protected by International Treaty.

    The only "right" people have for mains wiring is to get Electricity from it. But Ethernet over Mains and HDMI over Mains are really transmitters now creating interference from 1MHz to 200MHz. Each new generation of "Homeplug" type gadget goes faster and blocks more frequencies.

    CE marks are not enforced or policed or properly independently verified so we have PSUs, CFL, chargers etc with filters left out to save cost which make Radio reception from 60Khz up to 20MHz or even weaker VHF-FM stations unusuable.
    Watty did you air your grievance to RTE and Comreg about the stupidity of the digital Dividend? Surely as you know what you are talking about from a technical point of view that they will realise you are correct when it applies to the new technology of 4G? :)


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    #19
    watty
    Registered Users Posts: 32,417 ✭✭✭✭watty


    It's nothing to do with RTE, they would be happy to keep 790MHz to 862MHz as it's likely the future of Broadcasting needs the Spectrum.

    TV3, TG3, RTE and RTENL get NOTHING from the "Digital Dividend".

    Comreg listen only to their "peers" in Ofcom and FCC etc. I've met them face to face. There are good Engineers there. The Policy setting managers don't listen to them.

    I've been at Comreg sponsored Conference on it and spoken to OECD attendees too.

    In the past I've worked with Communications & Telecomms Engineers from USA, Switzerland, Czech Republic, Netherlands, Slovakia, Ireland, Israel, Hong Kong and South Africa.

    There is a collective madness in Regulator circles and unwillingness to tackle Gadget makers and unbelievable and illogical belief in Mobile and Satellite Technologies. The Irish Government is at the forefront of the lunacy with the NBS.

    Irish NBS (National Broadband Scheme) customers are ineligible to join the "Sam knows" white box scheme funded by EU to measure Broadband quality as it doesn't meet the minimum criteria for Broadband!

    Nor are Satellite Terminal users eligible. :)

    Comreg and Government are convinced the Digital Dividend is worth €250M to €500M, it's not unless the Mobile Operators are stupid. The entire value is predicated purely on the theory that there will be 4 Mobile operators in 30MHz + 30MHz roughly of spectrum delivering "Broadband". Sheer baloney. Maybe with Fixed Wireless, it's only just possible. certainly not with Mobile. Even with 120 + 120MHz of spectrum LTE might only just do entry level broadband. If there was enough base stations. But only in the very most rural areas is the minimum cell size appropriate to 800MHz band small enough. That could be better served with LTE on 1800MHz which is under used by the GSM operators.

    Also 2.3GHz (2,300MHz) is held by Eircom and virtually unused for years. They are NOT a state company. By LAW they should have lost the spectrum (principle is you are forbidden to "sit" on Spectrum).


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    #20
    lucernarian
    Registered Users Posts: 9,235 ✭✭✭lucernarian


    On a practical note I find it hard to get good quality amps that have f-connector inputs, are screened and also are grouped. In any case, there's very little that can be done until aerials and amps are finally manufactured to not specifically receive 800MHz broadcasts. I.e. Group C/D aerials and combiners etc. no longer tuned specifically to work from Ch. 61 to 69.


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    #21
    The Cush
    Registered Users Posts: 15,522 ✭✭✭✭The Cush


    To_be_confirmed wrote: »
    In any case, there's very little that can be done until aerials and amps are finally manufactured to not specifically receive 800MHz broadcasts. I.e. Group C/D aerials and combiners etc. no longer tuned specifically to work from Ch. 61 to 69.

    With the top end of the band lost from broadcasting throughout Europe I wonder if aerial manufacturers have plans to revise existing aerial grouping or introduce new aerial groups in the coming years, add to that a potential loss of another slice of spectrum to Digital Dividend 2 in the next 10-13 years.


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    #22
    watty
    Registered Users Posts: 32,417 ✭✭✭✭watty


    A second so called "Digital Dividend" may not happen. That was planned before HD and 3D.

    Also if the Mobile operators have any wit they will not bid silly prices on the first one.


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    #23
    The Cush
    Registered Users Posts: 15,522 ✭✭✭✭The Cush


    watty wrote: »
    A second so called "Digital Dividend" may not happen. That was planned before HD and 3D.

    Digital Dividend 2 is only being planned now.

    The push is coming from countries in the eastern part of Europe where Digital Dividend 1 is not fully available due to their border with Russia who I believe do not plan to release this spectrum in harmonisation with the EU.

    Finland started the ball rolling in 2010. It's down for discussion at WRC2012. Legislation making its way in Europe requires a further 1200MHz of spectrum to be identified for release by 2015 which would include Ch 49-60.

    Comreg plan to consult on DD2 in the middle of the year and this is what the Dept says
    As 2020 approaches there will be pressure for a second digital dividend before 2025. It may even be that the TV services will loose spectrum above 694MHz by 2020. This would mean that channels 49-60 would cease to be available for DTT.

    It may not happen or they may allocate a smaller slice under pressure for broadcasters etc., who knows what will happen in the next 13 years.


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    #24
    Sponge Bob
    Banned (with Prison Access) Posts: 25,234 ✭✭✭✭Sponge Bob


    The Cush wrote: »
    It may not happen or they may allocate a smaller slice under pressure for broadcasters etc., who knows what will happen in the next 13 years.

    I have been saying we should release 700mhz+ for a DD2 for years around here.

    The Finns suggest making Mobile and TV EQUAL Primary users across the entire 470-790mhz band. I think this is mad. I would allow countries to decide which of TV or Mobile is the primary user from 694mhz to 790mhz and subject to Co Ordination with a neighbour who chooses to continue to use 694-790mhz for TV as now.

    Officially since WRC 2007 the Digi Divvy band from 790-864mhz is a Co Primary user with Mobile and TV is still allowed in that band but the EU has told TV to bugger off out of there by ASO time.

    I do not support a blanket Primary user protection for TV between 694 and 790mhz. What about a country with only 2 TV channels and them both crap. They don't need a full 320mhz blocked off do they, they could use 50 mhz and an SFN and have plenty of wiggle room. Even without an SFN they would probably be able to do it.

    So Co Primary only per country and after co - ordination and subject to the rights of neighbouring countries to remain as is. If Ireland wants the UK out of 694mhz to 790mhz...in Wales and NI...... we must pay for the work involved IN THE UK out of our spectrum licence fees...and then only if the UK agree to move in the first place.


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    #25
    watty
    Registered Users Posts: 32,417 ✭✭✭✭watty


    I'd support that, but ONLY if the entirety of 700MHz to 960MHz is fixed Wireless.

    the 700MHz to 790MHz is pointless for Mobile.

    Actually we should have Oireachtas TV as well as the other Four channels (the RTE News Now, RTE+1 and RTEjr are not real channels). We may have 7 or 8 rubbish channels, but that's no excuse to Cripple Broadcast forever to have more "midband" services.

    But if the existing channels and Oireachtas TV are to be HD and maybe 3D content the 700MHz to 790MHz is needed.

    It's short sighted to flog off Broadcast Spectrum for Mobile services that will be no better than existing ones, when in reality there is no genuine spectrum shortage. The Digital Dividend isn't needed.

    More intelligent use of all the Mobile bands from 872MHz to 2300MHz is needed. The 2.5GHz could be fixed or Mobile.
    Mobile Nomadic on 3.6GHz should be illegal and it should be fixed only.


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    #26
    watty
    Registered Users Posts: 32,417 ✭✭✭✭watty


    SFN have lots of limitations. You can't do them everywhere. The delay between signals arriving can't exceed the symbol guard time. They were over hyped.


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    #27
    reslfj
    Registered Users Posts: 876 ✭✭✭reslfj


    Sponge Bob wrote: »
    I have been saying we should release 700mhz+ for a DD2 for years around here.
    That doesn't necessarily make it a good idea - does it? :p
    Sponge Bob wrote: »
    ... They don't need a full 320mhz blocked off do they, they could use 50 mhz and an SFN and have plenty of wiggle room.

    The ROI cannot use all channels - they must be shared with NI and the rest of the UK. The UK will have an even bigger sharing problem with NL, BE and FR. SFN is not a fix for all spectrum problems. Some bit-rate is also lost using SFN's due to the needed guard and the PP (pilot pattern) used.
    watty wrote: »
    SFN have lots of limitations. You can't do them everywhere. The delay between signals arriving can't exceed the symbol guard time. They were over hyped.

    DVB-T SFN's does work nicely in most places within areas of 60-100 km in diameter. But ín addition to limits in signal arrival delays, large country-wide SFN's will often suffer from problems with network self-interference.
    This is the sum of all signals received from SFN TX sites arriving outside the guard time. Each a very small signal level, but the sum of the many interference signals can be larger than allowed for reception of the multiplex.

    Lars :)


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    #28
    The Cush
    Registered Users Posts: 15,522 ✭✭✭✭The Cush


    The Cush wrote: »
    How will viewers with Group C/D and Wideband aerials (and masthead amps) be effected by the launch of mobile services above Ch 60?

    This appears to be of concern to RTÉ/RTÉNL and not to the Dept or Comreg as can be seen from a series of emails between then in the last few months, published recently by Comreg.

    RTÉNL says it's a policy issue for Comreg but Comreg says any interference problems are a technical issue for RTÉNL/installers/viewers to resolve.

    RTÉNL have now added the following caveat to the RTÉNL -Saorview FAQ regarding aerial installations that could be subject to interference from future non-broadcast services above UHF Ch 60.
    Some existing aerials, that work fine now, may require filtering at some time in the future as other, non broadcast, services move into adjacent frequency bands.

    http://www.rtenl.ie/wp-content/uploads/2012/01/RTÉNL-SAORVIEW-FAQs-Jan-2012-Rev-6.0.pdf, page 13

    This warning is highlighted 5 times in the FAQ
    The spectrum used for wireless services is becoming more and more congested. This includes the radio spectrum used for television broadcasting which is reducing. As different services are moving closer and closer together cross service interference becomes more of an issue. If you are doing work, or having work done on your television aerial, RTÉNL recommend that you ensure that the aerial is restricted, in so far as is possible, to the television broadcast band only (UHF channel 21 to 60). To protect your television services against interference into the future frequencies / channels above and below this should be filtered out.

    http://www.rtenl.ie/wp-content/uploads/2012/01/RTÉNL-SAORVIEW-FAQs-Jan-2012-Rev-6.0.pdf, pages 13,21,22,23,31

    The Saorview - Your Aerial page hasn't been updated with the above information yet
    There are a number of simple tests to help you determine if your aerial will receive the SAORVIEW signal:

    1. If you currently receive TV3 as an analogue service through your aerial then your aerial is most likely fine and is pointing in the right direction. You should not need to do anything with your aerial.


  • Options
    #29
    The Cush
    Registered Users Posts: 15,522 ✭✭✭✭The Cush


    Information has now been added to the Dept of Communications website on interference to TV services from mobile services. A link to an LTE/GSM rejection filter is also included.
    Spectrum Policies and the Digital Dividend

    Spectrum Policies

    The successful delivery of spectrum policies and the realisation of their potential is important for the Department, and involves balancing the competing demands of different, though converging, sectors. Priorities must be determined and a way forward identified while recognising that there could be competing cross departmental sector policies that need to be taken into account, as spectrum is a major and critical enabler for the different sector developments.

    The Digital Dividend is regularly referred to when the radio spectrum is being discussed. It is the spectrum that will be released following the migration of terrestrial television broadcasting from the traditional analogue transmission to digital transmission. This will occur in the UHF band in Ireland after 2012.

    Whilst the Irish TV services are now available by Digital TV to most of the country, since the number of services carried on Digital Terrestrial Television is less than had been anticpated, it will be possible to introduce other services into digital dividend sooner than had been anticpated.

    As the manager of our spectrum resource, ComReg has a major role to play in ensuring that the success of this process is realised. ComReg have recently indicated (ComReg 10/59) that they intend to bundle the digital dividend spectrum with the existing 900MHz cellular telephony spectrum in a future compeition.

    In order to ensure compatiblity (see EBU article) between the new "LTE" mobile telephony systems (on frequencies previously used for analogue TV) and the Digital Terrestrial Television system, it is likely that some viewers will have to have a filter installed to reduced the strength of the cellular signal at their TV or Set Top Box. Typical filters are being tested by ComReg. Such filters may be needed in cases where the DTT signals are above channel 51 and in particular in cases where channel 58 (770MHz) or 59 (778MHz) are to be used by DTT. That is installations using the "group C/D" type aerial.

    Installations (for reception of Saorview DTT above channel 51) in areas at the edge of a DTT transmitter service area or which use a mast head amplifier will most likely need a filter. This is because mast head amplifiers are prone to an "overload" condition if the signal level from either DTT or other sources is very strong. Mast head amplifiers should ideally only be used where necessary for reception of DTT. Excessive amplification of a DTT signal can cause set top boxes to appear not to be able to decode the DTT service.

    The Saorview coverage checker can be used to indicate whether the DTT transmissions serving an area are likely to be in channel 51 or higher.

    There is a lot to be done between now and the cessation of analogue television services in the UHF band. The Department will fully engage with ComReg and the other stakeholders involved in order to deliver the best results for Ireland.

    Last Updated:30/01/2012

    http://www.dcenr.gov.ie/Communications/Business+and+Technology/Digital+Dividend/


  • Options
    #30
    The Cush
    Registered Users Posts: 15,522 ✭✭✭✭The Cush


    The Cush wrote: »
    Information has now been added to the Dept of Communications website on interference to TV services from mobile services. A link to an LTE/GSM rejection filter is also included.

    Webpage updated 7th Feb
    Spectrum Policies and the Digital Dividend

    Spectrum Policies

    The successful delivery of spectrum policies and the realisation of their potential is important for the Department, and involves balancing the competing demands of different, though converging, sectors. Priorities must be determined and a way forward identified while recognising that there could be competing cross departmental sector policies that need to be taken into account, as spectrum is a major and critical enabler for the different sector developments.

    The Digital Dividend is regularly referred to when the radio spectrum is being discussed. It is the spectrum (790-862MHz) that will be released following the migration of terrestrial television broadcasting from the traditional analogue transmission to digital transmission. This will occur in the UHF band in Ireland after 2012.

    Whilst the Irish TV services are now available by Digital TV to most of the country, since the number of services carried on Digital Terrestrial Television is less than had been anticipated, it will be possible to introduce other services into digital dividend sooner than had been anticipated.

    As the manager of our spectrum resource, ComReg has a major role to play in ensuring that the success of this process is realised. ComReg has recently indicated (ComReg 10/59) that it intends to bundle the digital dividend spectrum with the existing 900MHz cellular telephony spectrum in a future competition.

    In order to ensure compatiblity (see EBU article) between the new "LTE" mobile telephony systems (on frequencies previously used for analogue TV) and the Digital Terrestrial Television system, it is likely that some viewers will have to have a filter installed to reduced the strength of the cellular signal at their TV or Set Top Box.

    Filters may be needed in cases where the DTT signals are above channel 51 (due to potential so called image channel “N+9” sensitivity of some receivers) and in cases where channel 58 (770MHz) or 59 (778MHz) are to be used by DTT. That is installations using the "group C/D" type aerial. It is stressed that difficulties may only arise at locations close to LTE base stations. Typical filters are being tested by ComReg, though for reception of channel 59 the filter will need to provide signal reductions above 790MHz whilst having a low loss in ch 59 (778MHz). ComReg has planned that ch 60 (786MHz) will not need to be used by the DTT services for which they are required to make spectrum available.

    The Saorview coverage checker can be used to indicate whether the DTT transmissions serving an area are likely to be in channel 51 or higher.


    Mast Head Amplifiers

    Installations which use a mast head amplifier for TV reception (irrespective of the frequencies to be received) will most likely need a filter. This is because mast head amplifiers are prone to an "overload" condition if the signal level from either DTT or other sources (on frequencies either above or below the TV signal) is very strong. In these overload conditions unintended signals called “intermodulation products” can be radiated causing interference to other users of the spectrum.

    Mast head amplifiers should only be used for reception of DTT where there is a clear need to do so. Excessive amplification of a DTT signal can cause set top boxes to appear not to be able to decode the DTT service.

    There is a lot to be done between now and the cessation of analogue television services in the UHF band. The Department will fully engage with ComReg and the other stakeholders involved in order to deliver the best results for Ireland.

    Last Updated:07/02/2012

    http://www.dcenr.gov.ie/Communications/Business+and+Technology/Digital+Dividend/


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    #31
    Ronnie Raygun
    Closed Accounts Posts: 1,351 ✭✭✭Ronnie Raygun


    This is a good read, even taking into account the fact the UK have far more low powered relays.


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