Loss of Freeview Channels with 4G Mobile

[CJB]

Is this really an issue - that many (all?) Freeview Channels will
suffer from severe interference with the new frequencies allocated to
4G mobile services?

I hear that millions of Londoners will be especially affected if
receiving Freeview from Crystal Palace transmitters / masts.

This is crazy. I thought that analogue t.v. was switched off to
provide frequencies for 4G, but it seems that Freeview frequencies are
to be allocated to 4G as well!!

I also heard that compensation will be made of £10K per household
affected. But isn't it illegal to deliberately affect t.v. / radio
reception, which apparently the 4G telcos will be doing.

CJB.

[Brian Gaff]

I'm not sure they really know how bad it will get. all the testing is as
always going to be done by the good old customers I fancy.

Brian

--
From the Bed of Brian Gaff.
The email is valid as bri...@blueyonder.co.uk
Blind user.
"CJB" <chris...@gmail.com> wrote in message
news:757ccee3-7168-4c92...@l18g2000vbv.googlegroups.com...

[Graham.]

On Fri, 16 Nov 2012 14:56:46 -0800 (PST), CJB <chris...@gmail.com>
wrote:

The UHF band was shared between DTT and analogue services, a channel
in a given area could be allocated to a DTT multiplex or a single
analogue service each slotted into the 8 MHz space.

Now that analogue has gone the remaining digital MUX's can be moved
within the band so as to provide contiguous spare spectrum that is to
be sold off for LTE.

I suppose you could look at that as "Free view frequencies being sold
off", but it's petty much a moveable feast.

Many people would say it was "criminal" to put the LTE allocation so
close to the top end of the (curtailed) UHF TV band, but each is a
licenced service so no real illegality. Just to be clear, there is no
actual overlap, it's just that the nature of phone masts is that they
are often sited near dwellings, and domestic receivers and amplifiers
might get swamped.

I thought Crystal palace used the LF end of the band, the problem is
more likley to affect the top of the band.



Where do I apply for my ten grand?




--
Graham.
%Profound_observation%

[Steve Terry]

Crazy is right, all existing and near future TVs have front ends that
receive UHF ch21 to 68, the 4G plans are to extend down to maybe
as low as ch50, so without extensive extra filtering all those 4G
transmitters will swamp TV tuners, even with filters they probably still
will.

IMHO It would have been fairer to have shut down UHF terrestrial
TV and supply all with Astra 2 dishes. Of course not all have a clear path
to the south east. ;-(

Seriously i can't suggest that UHF Terrestrial TV is viable anymore.
Get a Dish if you can see 28e, and tell all you can to do the same.

Interference free UHF TV is dead.

Steve Terry
--
Get a free GiffGaff PAYG Sim and �5 bonus after activation at:
http://giffgaff.com/orders/affiliate/gfourwwk

[ne...@address.invalid]

On Sat, 17 Nov 2012 03:22:48 -0000, "Steve Terry" <gfou...@tesco.net>
wrote:

>
>Seriously i can't suggest that UHF Terrestrial TV is viable anymore.
>Get a Dish if you can see 28e, and tell all you can to do the same.
>
>

Which is *precisely* what you are intended to conclude, in order to
clear the way for eventual closure.

[The Natural Philosopher]

Not true.
Unless there is a 4g mast directly between you and the TV transmitter
its unlikely you will be affected and the TVs are transmitting at 100kW
or so, The 4G at a few watts only.

There is no point in making the phone transmitters much more powerful
since they are 2 way stations and your 4G phone wont do more than a watt
if that.

And your TV aerial wont recieve much off the main beam either.


No point being able to receive 4G if you cant send..

Old Orange on 900 Mhz is also close..it doesn't represent a problem.




>
> Steve Terry
>


--
Ineptocracy

(in-ep-toc’-ra-cy) – a system of government where the least capable to
lead are elected by the least capable of producing, and where the
members of society least likely to sustain themselves or succeed, are
rewarded with goods and services paid for by the confiscated wealth of a
diminishing number of producers.

[Jim Lesurf]

In article
<757ccee3-7168-4c92...@l18g2000vbv.googlegroups.com>,
CJB

<chris...@gmail.com> wrote:
> Is this really an issue - that many (all?) Freeview Channels will suffer
> from severe interference with the new frequencies allocated to 4G mobile
> services?

Hard to predict the scope. But even OfCom keep coming up with estimates of
the order of a million households being seriously affected. And there do
seem grounds to suspect this under-estimates.

> I hear that millions of Londoners will be especially affected if
> receiving Freeview from Crystal Palace transmitters / masts.

There are, broadly speaking, two aspects to the problem:

1) That the new 4G transmissions will be so powerful that they simply swamp
or overload 'Freeview' receivers. So a user gets no 'Freeview' TV at all,
regardless of the actual frequencies of the TV broadcasts in their area.

2) That in some areas the 'reshuffled' TV transmission frequencies will
still be *very* close to the 4G transmission frequencies. So may require
essentially military grade protection filtering in many homes. The effects
here will vary from home to home.

CP reception may well be hit by (1) even if the TV transmissions from it
are well away from 4G in frequency terms. However the wide frequency
spacing improves the chance that an added filter will be a fix. In other
areas it is questionable if any filter would be a practical solution at any
sensible price.

> This is crazy.

<ahem> It is official policy. I'd agree that it was a Courageous Decision.

> I thought that analogue t.v. was switched off to provide frequencies for
> 4G, but it seems that Freeview frequencies are to be allocated to 4G as
> well!!

That decision has been made. Indeed, internationally agreed as a
'co-ordination' to help manufacturers sell their kit across the world.

The idea is that they "will no longer *be* 'Freeview' frequencies". :-)

You may have noticed that the concern of Government and OfCom does seem
to be to aid big companies. Quite understandable if The Chancellor looks
forward eagerly, hoping for a few billion quid from the mobile companies
buying 4G bandspace. And he may even hope they will pay more tax in the UK
as a result. He does seem an optimistic chap... ;->

Do they teach any engineering at Eton, I wonder...

> I also heard that compensation will be made of £10K per household
> affected. But isn't it illegal to deliberately affect t.v. / radio
> reception, which apparently the 4G telcos will be doing.

AIUI It will be 'legal' if the transmission parameters meet the specs
agreed with OfCom. Those specs may be thought insane by some mere
engineers. But legal, so far as suits are concerned. By default it then
becomes your problem as the TV viewer. The telcos will have government
permission to do as they are doing. That makes it legal.

Although there are plans for a 'MitCo' to hand out free sweeties... erm
filters, etc, in a Lady Bountyful act in the hope it will calm any public
anger and avoid a fuss... erm solve (some of) the problems. Or at least
some of the initial problems.

BTW A letter from OfCom to the minister states that filters are nominally
available "now". So I have started asking around for one or two of these
"available" filters to test. As yet, I'm happy that I decided not to hold
my breath whilst awaiting one arriving. :-) And the ones I've seen test
results for didn't seem a panacea to me.

If that doesn't satisfy, you'd have to direct complaints to your
politicians for sleeping though allowing this to happen. Then see if they
do anything useful. Bear in mind that they are clueless about any
engineering or technical topic, though.

FWIW I have no idea how bad this will be. I doubt anyone really does
(including OfCom). But I've read enough to think it likely that there will
be widespread problems. A million homes *is* a minority. But it is still a
lot of annoyed people. And it could be much worse.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

[Percy]

On Sat, 17 Nov 2012, "Steve Terry" writ:

>CJB wrote:
>> Is this really an issue - that many (all?) Freeview Channels will
>> suffer from severe interference with the new frequencies allocated to
>> 4G mobile services?
>>
>> I hear that millions of Londoners will be especially affected if
>> receiving Freeview from Crystal Palace transmitters / masts.
>>
>> This is crazy. I thought that analogue t.v. was switched off to
>> provide frequencies for 4G, but it seems that Freeview frequencies are
>> to be allocated to 4G as well!!
>>
>> I also heard that compensation will be made of £10K per household
>> affected. But isn't it illegal to deliberately affect t.v. / radio
>> reception, which apparently the 4G telcos will be doing.
>> CJB.
>>
>Crazy is right, all existing and near future TVs have front ends that
>receive UHF ch21 to 68, the 4G plans are to extend down to maybe
>as low as ch50, so without extensive extra filtering all those 4G
>transmitters will swamp TV tuners, even with filters they probably still
>will.
>
>IMHO It would have been fairer to have shut down UHF terrestrial
>TV and supply all with Astra 2 dishes. Of course not all have a clear path
>to the south east. ;-(

What happens when a huge meteor shower or solar flare wipes out the
Astra satellites?

You'll be glad of a UHF service to fall back on.
--
P

[Jim Lesurf]

In article <k87qkk$r73$1...@news.albasani.net>, The Natural Philosopher

<t...@invalid.invalid> wrote:
> On 17/11/12 03:22, Steve Terry wrote:
> > CJB wrote:

> >
> > Seriously i can't suggest that UHF Terrestrial TV is viable anymore.
> > Get a Dish if you can see 28e, and tell all you can to do the same.
> >
> > Interference free UHF TV is dead.
> Not true.

I'm sure you are correct in thinking that many people will soldier on using
DTTV. But for others it will likely prove impractical. How large that
minority may be, time will tell...

> Unless there is a 4g mast directly between you and the TV
> transmitter its unlikely you will be affected and the TVs are
> transmitting at 100kW or so,

Sweeping assertion. Not true for all TXs.

> The 4G at a few watts only.

Not sure where you are getting that figure from. Maybe you are assuming
4G is like earlier generations. However on OfCom's own figures...

The proposed 4G base stations are 61dBm per 5Mhz block, and there are
six of them per base. So more like over 6kW EIRP per fully used base
station. Not what I'd dismiss as "a few watts". The real challenge is these
base stations, not the mobiles.

BTW if you check out the measurements done by BBC R&D the 4G signals can
work as very power-efficient jammers when *not* fully used. So low 4G use
factors in a cell may not help.

Many DTTV TXs are in the 10 - 20 kW range. Particularly, as it happens in
areas of the UK where OfCom expect ch59/60 to go on being used. i.e. up to
about 1 MHz away from the 4G.

The base stations are also often rather closer than the TV TXs. In the town
where I live the TV TXs are roughly 25 and 75 km away. Whereas the sites
for existing base stations mean they are within 500 meters of most houses.
I'd suspect from previous work on mobile that this sort of situation is
fairly common.

> And your TV aerial wont recieve much off the main beam either.

Interesting example of an absolute and sweeping assertion based on using a
vague term. :-)

I can't recall you visiting me and checking the antennas I use, though. Did
you check everyone else in the UK whilst I was out? :-) Nor have I seen you
assessing how much may be scattered into the main lobes by surroundings. I'll
look forwards to you publishing your measured results.

Which of the OfCom documents on this had you read *before* making your
posting? If you think the signals are "a few watts" I'm wondering where
your sweeping conclusions are coming from. Had you also read the BBC
reports on their measurements on how 4G affects a range of examples of
existing DTTV RXs?

To me, the 4G situation looks a tad different to previous mobile
generations in a number of ways. I'm sure many people won't get a problem.
But I also think we have grounds to suspect many others *will* get a problem.
Alas, I don't think even OfCom really know how many. Their estimates have
varied quite a lot.

[David Woolley]

Jim Lesurf wrote:

>
> 1) That the new 4G transmissions will be so powerful that they simply swamp
> or overload 'Freeview' receivers. So a user gets no 'Freeview' TV at all,
> regardless of the actual frequencies of the TV broadcasts in their area.

I suspect in a lot of cases, only one or two multiplexes will be
affected and only in certain weather conditions, probably without total
loss of signal. Many people will grin and bear it, without
understanding the nature of the problem.

[ne...@address.invalid]

On Sat, 17 Nov 2012 11:22:16 +0000, Percy <Pe...@no.chance> wrote:

>
>What happens when a huge meteor shower or solar flare wipes out the
>Astra satellites?
>

I don't know what happens, since it never has.

>You'll be glad of a UHF service to fall back on.
>

Providing of course that the UHF transmitter is not satellite fed.

And since so much of our life is now serviced by satellite links and
other facilities that would be knocked out by the same catastrophic
event, I would have much worse concerns than whether I could receive
TV programmes.

[Jim Lesurf]

In article <k883nu$ng$1...@dont-email.me>, David Woolley

<da...@ex.djwhome.demon.invalid> wrote:
> Jim Lesurf wrote:

> >
> > 1) That the new 4G transmissions will be so powerful that they simply
> > swamp or overload 'Freeview' receivers. So a user gets no 'Freeview'
> > TV at all, regardless of the actual frequencies of the TV broadcasts
> > in their area.

> I suspect in a lot of cases, only one or two multiplexes will be
> affected and only in certain weather conditions, probably without total
> loss of signal.

It seems likely that will happen to some. Just as some will be unaffected,
and others lose all DTTV. The difficulty is knowing in advance how many
cases of each kind will occur. The studies I've seen just seem to make
assumptions those doing the study guess are 'plausible'. So output a wide
range of numbers.

> Many people will grin and bear it, without understanding the nature of
> the problem.

If the meedja continue to take no interest, then yes, I suspect many people
will have no idea of the cause of a problem caused by 4G. So may end up
being flogged a Sky package with OfCom blissfully unaware of the real
number of such cases.

I wonder if The Sun will start telling its readers. "If your TV stops
working well, just ask OfCom/MitCo for help. Whatever you do, *don't* buy a
Sky package without knowing what went wrong!" :-)

[alexd]

Jim Lesurf (for it is he) wrote:

> The proposed 4G base stations are 61dBm per 5Mhz block, and there are
> six of them per base. So more like over 6kW EIRP per fully used base
> station. Not what I'd dismiss as "a few watts". The real challenge is
> these base stations, not the mobiles.

But inverse square law! The handsets are going to be mere metres away from
TV sets, with a constant low level of traffic keeping the authorities up to
date with your behaviour, er sorry, keeping your social network status up to
date.

--
<http://ale.cx/> (AIM:troffasky) (UnSoEs...@ale.cx)
13:57:18 up 2 days, 17:02, 5 users, load average: 0.88, 0.89, 0.79
Qua illic est reprehendit, illic est a vindicatum

[Peter Duncanson]

That may be the case with entertainment TV.

However, TV is probably the main means of informing the population about
catastrophes whether local or national.

Warnings about weather events can save lives and injury weather they're
just about icy roads or about major storms.


--
Peter Duncanson
(in uk.tech.digital-tv)

[Scott]

On Fri, 16 Nov 2012 14:56:46 -0800 (PST), CJB <chris...@gmail.com>
wrote:

Obtaining a licence from the Government normally cures any problems
with legality :-)

[Mark Carver]

Peter Duncanson wrote:

> However, TV is probably the main means of informing the population about
> catastrophes whether local or national.

Like it or not, 'Social Media' via smartphones is rapidly taking over from TV
and radio broadcasting for that function.

There was a major fire near here a couple of of years ago, You Tube etc filled
up with videos of it almost within minutes, several hours before BBC South and
ITV Meridian broadcast the news; oh, and guess where they lifted the pictures
from ?

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

www.paras.org.uk

[Peter Duncanson]

On Sat, 17 Nov 2012 15:06:38 +0000, Peter Duncanson
<ma...@peterduncanson.net> wrote:

>Warnings about weather events can save lives and injury weather they're
>just about icy roads or about major storms.

Good grief! That second "weather" should be "whether"

[Bill Wright]

Percy wrote:

> What happens when a huge meteor shower or solar flare wipes out the
> Astra satellites?
>
> You'll be glad of a UHF service to fall back on.

Especially since the public libraries are under threat. Never mind,
there's always that pile of Milnes and Boon book in the attic.

Bill

[Bill Wright]

Jim Lesurf wrote:

>> Unless there is a 4g mast directly between you and the TV
>> transmitter its unlikely you will be affected

You seem to think that the directional characteristics of Group A and B
aerials are the same on channels 61+ as they are lower down the band.

and the TVs are
>> transmitting at 100kW or so,
>
> Sweeping assertion. Not true for all TXs.

Many local relays, in fact, have powers in the hundreds or tens of watts.

Bill

[Bill Wright]

Jim Lesurf wrote:

> I wonder if The Sun will start telling its readers. "If your TV stops
> working well, just ask OfCom/MitCo for help. Whatever you do, *don't* buy a
> Sky package without knowing what went wrong!" :-)

Sky were out in force in DSO areas, signing people up like billio. Some
people were under the impression that they would have to get Sky because
the local relays were going to be switched off completely. Goodness
knows who told them that.

Bill

[The Natural Philosopher]

On 17/11/12 11:15, Jim Lesurf wrote:
> In article
> <757ccee3-7168-4c92...@l18g2000vbv.googlegroups.com>,
> CJB
> <chris...@gmail.com> wrote:
>> Is this really an issue - that many (all?) Freeview Channels will suffer
>> from severe interference with the new frequencies allocated to 4G mobile
>> services?
>
> Hard to predict the scope. But even OfCom keep coming up with estimates of
> the order of a million households being seriously affected. And there do
> seem grounds to suspect this under-estimates.
>
>> I hear that millions of Londoners will be especially affected if
>> receiving Freeview from Crystal Palace transmitters / masts.
>
> There are, broadly speaking, two aspects to the problem:
>
> 1) That the new 4G transmissions will be so powerful that they simply swamp
> or overload 'Freeview' receivers. So a user gets no 'Freeview' TV at all,
> regardless of the actual frequencies of the TV broadcasts in their area.
>

what is the point of making them Megawatt level when what they connect
to has at best a 1W device in it to reply with?

<snip content free bollocks>

[charles]

In article <k88ukn$3ij$1...@speranza.aioe.org>,

and some have powers below 10 watts

--
From KT24

Using a RISC OS computer running v5.18

[Woody]

"Bill Wright" <bi...@invalid.com> wrote in message
news:k88ukn$3ij$1...@speranza.aioe.org...

As much as that? I was on one in mid-Wales this week that had a
Tx output of 28.3dBm or about 676mW - plus antenna gain of course
but since they were a phased pair of short log-periodics I doubt
the erp was much more than a couple of watts!



--
Woody

harrogate three at ntlworld dot com

[Woody]

[snip]

>
> what is the point of making them Megawatt level when what they
> connect to has at best a 1W device in it to reply with?
>

[snip]

It is called reciprocity and is something that is being heartily
ignored in this thread.

Because a site is licenced for 32dBW (about 1200W) it does not
mean it has to use anything like that!

[The Natural Philosopher]

On 17/11/12 12:15, Jim Lesurf wrote:
> In article <k87qkk$r73$1...@news.albasani.net>, The Natural Philosopher
> <t...@invalid.invalid> wrote:
>> On 17/11/12 03:22, Steve Terry wrote:
>>> CJB wrote:
>
>>>
>>> Seriously i can't suggest that UHF Terrestrial TV is viable anymore.
>>> Get a Dish if you can see 28e, and tell all you can to do the same.
>>>
>>> Interference free UHF TV is dead.
>> Not true.
>
> I'm sure you are correct in thinking that many people will soldier on using
> DTTV. But for others it will likely prove impractical. How large that
> minority may be, time will tell...
>
>
>> Unless there is a 4g mast directly between you and the TV
>> transmitter its unlikely you will be affected and the TVs are
>> transmitting at 100kW or so,
>
> Sweeping assertion. Not true for all TXs.
>
>
>> The 4G at a few watts only.
>
> Not sure where you are getting that figure from. Maybe you are assuming
> 4G is like earlier generations. However on OfCom's own figures...
>
> The proposed 4G base stations are 61dBm per 5Mhz block, and there are
> six of them per base. So more like over 6kW EIRP per fully used base
> station. Not what I'd dismiss as "a few watts". The real challenge is these
> base stations, not the mobiles.
>

Rubbish. The base stations have to receive from the mobiles: OK they can
have decent antenna gain while the mobiles may not but its not going to
make THAT much difference..

There is no point having someone shout at you if you can only whisper
back. Ergo there is NO POINT in having kilowatts at the base stations.
If your 4G phone is knocking out 100mW in return for the up channel.



You will get interference from your 4g mobile - NOT the base station.

> BTW if you check out the measurements done by BBC R&D the 4G signals can
> work as very power-efficient jammers when *not* fully used. So low 4G use
> factors in a cell may not help.

Never said they would.

>
> Many DTTV TXs are in the 10 - 20 kW range. Particularly, as it happens in
> areas of the UK where OfCom expect ch59/60 to go on being used. i.e. up to
> about 1 MHz away from the 4G.
>

I think you will find they are mostly being uprated. Still that's only
10dB off 100KW.

> The base stations are also often rather closer than the TV TXs. In the town
> where I live the TV TXs are roughly 25 and 75 km away. Whereas the sites
> for existing base stations mean they are within 500 meters of most houses.
> I'd suspect from previous work on mobile that this sort of situation is
> fairly common.
>
>> And your TV aerial wont recieve much off the main beam either.
>
> Interesting example of an absolute and sweeping assertion based on using a
> vague term. :-)
>

Based on experience of even a simple bloody loop antenna. Are you an RF
circuit designer? well I was,. So piss off. Most people who have 'bought
a digital aerial' will have a main beam of only 10-10 dgegrees.

> I can't recall you visiting me and checking the antennas I use, though. Did
> you check everyone else in the UK whilst I was out? :-) Nor have I seen you
> assessing how much may be scattered into the main lobes by surroundings. I'll
> look forwards to you publishing your measured results.

You really are clueless.

>
> Which of the OfCom documents on this had you read *before* making your
> posting? If you think the signals are "a few watts" I'm wondering where
> your sweeping conclusions are coming from. Had you also read the BBC
> reports on their measurements on how 4G affects a range of examples of
> existing DTTV RXs?
>

If you are equipping 4gh handsets with more than a few watts you are
going to fry the brains of anyone using them.

Mind you, in your case it seems to have happened already.

What POINT is there of shoving 60,000 times ore power into the base
station when it wont be able to receive anything from the handset anyway?

Its is TWO WAY channels dear boy.

> To me, the 4G situation looks a tad different to previous mobile
> generations in a number of ways. I'm sure many people won't get a problem.
> But I also think we have grounds to suspect many others *will* get a problem.
> Alas, I don't think even OfCom really know how many. Their estimates have
> varied quite a lot.
>

The short answer is that a very very few people will get problems, which
they will solve by swotching off their silly 4G phones when watching TV.

A vanishingly small amount of people in exactly the wrong place with
their aerials pointing straight at a nearby base station will get
problems: Most of those will be solved by sticking a decent filter on
the antenna.

The problems of ham radio operators smashing DSL are far far larger, and
the problems of homeplugs smashing ham radio reception arer even larger.

Of course its all futile anyway because there isn't the spectral width
to get more than a few hundred people whacking out 40Mbnps anyway.
Which is why radio wont ever compete with fibre or copper coax for
dense areas.

The only way is to have lots of little base stations of LIMITED range
serving just a few people.

I mean - look at WiFi now anyway. You cant cram more into a spectrum
than Nyquist and shannon allow.



> Slainte,
>
> Jim

[The Natural Philosopher]

On 17/11/12 20:29, Peter Duncanson wrote:
> On Sat, 17 Nov 2012 15:06:38 +0000, Peter Duncanson
> <ma...@peterduncanson.net> wrote:
>
>> Warnings about weather events can save lives and injury weather they're
>> just about icy roads or about major storms.
>
> Good grief! That second "weather" should be "whether"
>

More evidence that mobile phones fry the brains of the idiots that use them.

[The Natural Philosopher]

The key is in the word 'local'

so the local RF field is the same strength

> Bill

[The Natural Philosopher]

Sky salesmen

[The Natural Philosopher]

On 17/11/12 21:44, Woody wrote:
> [snip]
>>
>> what is the point of making them Megawatt level when what they
>> connect to has at best a 1W device in it to reply with?
>>
> [snip]
>
> It is called reciprocity and is something that is being heartily
> ignored in this thread.
>
> Because a site is licenced for 32dBW (about 1200W) it does not
> mean it has to use anything like that!
>

Or indeed that it will show any useful performance gain when so doing.

[David Woolley]

The Natural Philosopher wrote:

>
> what is the point of making them Megawatt level when what they connect
> to has at best a 1W device in it to reply with?

MW sounds a bit high, but the base station is transmitting to multiple
mobiles at once, and some people suggest that the downlink bit rate is a
lot higher than the uplink one, even for a single mobile's share of it.

The base station receiver will be in a low noise environment, and they
can afford to spend money on low noise front ends.

I seem to remember that TACS used about 25 watts per channel, at the
base stations. That was for a low speed channel with symmetric rates.

[Nick Leverton]

In article <k894ih$5vj$1...@dont-email.me>,

At $DAYJOB we make radio heads that convert the baseband mobile signals
into radio. The power range has crept upwards to 40W per channel and
I think we are now being asked to look at devices for 100W channels,
of which I gather the mobile companies may in some cases use several at
the top of a mast to give zonal coverage.

It's quite a challenge to get the dynamic power corrections right without
the device immolating itself, fortunately I don't work on the RF side !

Nick
--
"The Internet, a sort of ersatz counterfeit of real life"
-- Janet Street-Porter, BBC2, 19th March 1996

[The Natural Philosopher]

That's about what I would expect running on 20-30 spread spectrum
channels simultaneously. Not for a single one.
At least 1000 times less (60dB) than the meanest TV transmitter.

In reality you would need to be at least 40dB up on that, so make that
100dB ratio in terms of distance


I,e you will probably get interference somewhere within 15 meters of a
tower.

Unless you overload the TV front end it will simply reject that mush
that a SST sends out.

[Bill Wright]

The Natural Philosopher wrote:
> On 17/11/12 21:12, Bill Wright wrote:
>> Jim Lesurf wrote:
>>
>>>> Unless there is a 4g mast directly between you and the TV
>>>> transmitter its unlikely you will be affected
>> You seem to think that the directional characteristics of Group A and B
>> aerials are the same on channels 61+ as they are lower down the band.
>>
>> and the TVs are
>>>> transmitting at 100kW or so,
>>>
>>> Sweeping assertion. Not true for all TXs.
>> Many local relays, in fact, have powers in the hundreds or tens of watts.
>>
> The key is in the word 'local'
>
> so the local RF field is the same strength
>
>> Bill

Of course, as a generalisation that's right. But the assertion that 'the
TVs are transmitting at 100kW' needed correction.

Bill

[Bill Wright]

The Natural Philosopher wrote:

>> Sky were out in force in DSO areas, signing people up like billio. Some
>> people were under the impression that they would have to get Sky because
>> the local relays were going to be switched off completely. Goodness
>> knows who told them that.
>>
> Sky salesmen

Blimey! Do you think they would?

Bill

[Bill Wright]

The Natural Philosopher wrote:

>> Because a site is licenced for 32dBW (about 1200W) it does not
>> mean it has to use anything like that!
>>
> Or indeed that it will show any useful performance gain when so doing.

I would have thought the licence would limit the site to the power level
necessary.

Bill

[The Natural Philosopher]

It probably does.

[Jim Lesurf]

In article <k88vsd$hv1$2...@news.albasani.net>, The Natural Philosopher

<t...@invalid.invalid> wrote:
> On 17/11/12 11:15, Jim Lesurf wrote:
> > In article
> >
> >

> > 1) That the new 4G transmissions will be so powerful that they simply
> > swamp or overload 'Freeview' receivers. So a user gets no 'Freeview'
> > TV at all, regardless of the actual frequencies of the TV broadcasts
> > in their area.
> >

> what is the point of making them Megawatt level when what they connect
> to has at best a 1W device in it to reply with?

In general terms, two reasons:

1) The system is intended to be used in an asymmetric manner. High rates
for the downlink so people can do things like watch good quality video.
Much lower rates for the uplink as that is mainly for command and control
or sending lower rate audio or video.

2) Each phone has only one uplink user. The base station has to cater for
many downlink users 'symultaneously'.

So the planned data bandwidths are very different for the base station
downllinks (plural) and the individual uplink (individual mobile).

Apply Shannon's Law and you find that the 4G bases end up wanting such high
EIRPs.

> <snip content free bollocks>

s / content free bollocks / bits Natural Philosopher didn't understand /
:-)

Have you not read the relevant OfCom/BBC documents yet? No sign in your
response that you have.

[Jim Lesurf]

In article <52f03ae9...@charleshope.demon.co.uk>, charles

It is perhaps also worth bearing in mind that one of the points of high
power 'main' TXs is to serve a larger area. Which results in those far from
the TV TX getting a low field strength compared to people nearer the TX. So
although served by a 'high power TV TX' they may also get problems from a
nearby 4G base station. As with all this, the devil will be in the details.

[Jim Lesurf]

In article <hzTps.303580$Wc4.1...@fx10.am4>, Woody

<harro...@ntlworld.spam.com> wrote:
> [snip]
> >
> > what is the point of making them Megawatt level when what they
> > connect to has at best a 1W device in it to reply with?
> >
> [snip]

> It is called reciprocity and is something that is being heartily
> ignored in this thread.

It is also worth those not familiar with this topic realising that the
values I've been quoting are EIRP as specified by OfCom, etc. i.e. *not*
the actual power squirted into the feed to be transmitted.

[Jim Lesurf]

In article <k89178$la1$1...@news.albasani.net>, The Natural Philosopher

<t...@invalid.invalid> wrote:
> On 17/11/12 12:15, Jim Lesurf wrote:
> > In article <k87qkk$r73$1...@news.albasani.net>, The Natural Philosopher
> > <t...@invalid.invalid> wrote:

> >
> > Not sure where you are getting that figure from. Maybe you are
> > assuming 4G is like earlier generations. However on OfCom's own
> > figures...
> >
> > The proposed 4G base stations are 61dBm per 5Mhz block, and there are
> > six of them per base. So more like over 6kW EIRP per fully used base
> > station. Not what I'd dismiss as "a few watts". The real challenge is
> > these base stations, not the mobiles.
> >

> Rubbish. The base stations have to receive from the mobiles: OK they can
> have decent antenna gain while the mobiles may not but its not going to
> make THAT much difference..

Sorry, you are showing that you don't actually understand the topic. Are
you also denying the values I've quoted from the OfCom / BBC documents.
(Which as yet you show no sign of having read.)

> There is no point having someone shout at you if you can only whisper
> back. Ergo there is NO POINT in having kilowatts at the base stations.
> If your 4G phone is knocking out 100mW in return for the up channel.

However OfCom and the 4G companies are making assumptions which differ
from yours.

> >
> > Many DTTV TXs are in the 10 - 20 kW range. Particularly, as it happens
> > in areas of the UK where OfCom expect ch59/60 to go on being used.
> > i.e. up to about 1 MHz away from the 4G.
> >
> I think you will find they are mostly being uprated. Still that's only
> 10dB off 100KW.

Again, you are showing a lack of knowledge of the topic, I'm afraid.

Yes, some low power TXs have been, and will be, increase in EIRP. But many
others won't because if they were they'd cause interference with other
service areas. The lower power TXs tend to 'fill in' where the main ones
have poor local field level due to topology, etc. Also consider the other
points I've made - which should already be well known to those familiar
with the topic - e.g. that the main TXs themselves may serve the outer
parts of their coverage area with relatively low field strengths, so people
there may get 4G problems. Being served by a high power TX may not help
someone who is close to the edge of service. Once that is understood, note
also that most of the area of a circle is more than half way to its edge.
Something broadcast engineers (and antenna installers) know quite well. :-)

> > The base stations are also often rather closer than the TV TXs. In the
> > town where I live the TV TXs are roughly 25 and 75 km away. Whereas
> > the sites for existing base stations mean they are within 500 meters
> > of most houses. I'd suspect from previous work on mobile that this
> > sort of situation is fairly common.
> >
> >> And your TV aerial wont recieve much off the main beam either.
> >
> > Interesting example of an absolute and sweeping assertion based on
> > using a vague term. :-)
> >
> Based on experience of even a simple bloody loop antenna. Are you an RF
> circuit designer? well I was,. So piss off.

You mean I have to "piss off" because I designed and built RF kit from
below 100MHz to over 300GHz? :-) Does my having been awarded National
NPL prizes, etc, for such work also invalidate my daring to disagree with
you? Or being one of the people who helped design the optics of the James
Clarke Maxwell Telescope for ROE in Hawai'i? Or being one of the designers
of the 100 - 400 GHz receivers for UKIRT on Hawai'i? Or.. sorry, I should
stop there I guess. ;->

> What POINT is there of shoving 60,000 times ore power into the base
> station when it wont be able to receive anything from the handset anyway?

Once you've read the OfCom/BBC documents you can ask them why they don't
understand that as well as yourself. :-)

[ne...@address.invalid]

On Sat, 17 Nov 2012 21:56:59 +0000, The Natural Philosopher
<t...@invalid.invalid> wrote:

>>
>Based on experience of even a simple bloody loop antenna. Are you an RF
>circuit designer? well I was,. So piss off.
>
>

>> I can't recall you visiting me and checking the antennas I use, though. Did
>> you check everyone else in the UK whilst I was out? :-) Nor have I seen you
>> assessing how much may be scattered into the main lobes by surroundings. I'll
>> look forwards to you publishing your measured results.
>
>You really are clueless.

How sad that you seek to derail a perfectly good technical discussion
by hurling insults at others who have made better points than
yourself.

>The short answer is that a very very few people will get problems, which
>they will solve by swotching off their silly 4G phones when watching TV.
>
>

So in a world where every man, woman and child has a mobile phone in
their hand/pocket/handbag, you expect them all to be turned off when
within range of a TV set or its PVR?

[ne...@address.invalid]

I could understand that he comes to the wrong conclusion due to lack
of or incorrect technical knowledge. No problem there.
But on a purely logical level does he really believe that the network
operators would choose to run their base transmitters at grossly
excessive powers, regardless of the equipment and energy costs this
would entail?

[Peter Duncanson]

On Sat, 17 Nov 2012 21:58:43 +0000, The Natural Philosopher
<t...@invalid.invalid> wrote:

>On 17/11/12 20:29, Peter Duncanson wrote:
>> On Sat, 17 Nov 2012 15:06:38 +0000, Peter Duncanson
>> <ma...@peterduncanson.net> wrote:
>>
>>> Warnings about weather events can save lives and injury weather they're
>>> just about icy roads or about major storms.
>>
>> Good grief! That second "weather" should be "whether"
>>
>More evidence that mobile phones fry the brains of the idiots that use them.

1. I did not post that message via a mobile phone.
2. I have a very basic mobile phone but I use it very rarely.

If my brain is fried there must be some other explanation.

--
Peter Duncanson
(in uk.tech.digital-tv)

[The Natural Philosopher]

On 18/11/12 09:39, Jim Lesurf wrote:
> In article <k88vsd$hv1$2...@news.albasani.net>, The Natural Philosopher
> <t...@invalid.invalid> wrote:
>> On 17/11/12 11:15, Jim Lesurf wrote:
>>> In article
>>>
>>>
>>> 1) That the new 4G transmissions will be so powerful that they simply
>>> swamp or overload 'Freeview' receivers. So a user gets no 'Freeview'
>>> TV at all, regardless of the actual frequencies of the TV broadcasts
>>> in their area.
>>>
>
>> what is the point of making them Megawatt level when what they connect
>> to has at best a 1W device in it to reply with?
>
> In general terms, two reasons:
>
> 1) The system is intended to be used in an asymmetric manner. High rates
> for the downlink so people can do things like watch good quality video.
> Much lower rates for the uplink as that is mainly for command and control
> or sending lower rate audio or video.
>

You know as little about RF as about IP protocols it seeems.

In order to GET a signal - ANY signal no matter how little data it
containsl - to a receicver, you have to have enough peak power to
overcome the noise.

peak power is what screws up TV, not average radiated power.

> 2) Each phone has only one uplink user. The base station has to cater for
> many downlink users 'symultaneously'.
>

That simply means its using its peak power more often to transmit the
packets. Not that the peak power is increased.

> So the planned data bandwidths are very different for the base station
> downllinks (plural) and the individual uplink (individual mobile).
>

But not the peak power.

> Apply Shannon's Law and you find that the 4G bases end up wanting such high
> EIRPs.

Er no. Not really. Yes, there is a case for upping the SNR x bandwith
element the transmitter to achieve asymmetric working BUT most of that
is actually achieved by using more of the spectrum than more power.

In the end its a non problem anyway. Except in the rarest of cases the
towers wont exceed TV ERP at any given location, and if they do, the
incorporation of a steep notch filter is not exactly rocket science. Nor
is it expensive. I wouls say that as with the digital switchover,
people will start using external plug in filters in the front end of
whatever their TV earial plugs into, and then in due course it will all
be built in at a cost of pence, into the tuner front ends. Or in fact
the aerial itself.

>
>> <snip content free bollocks>
>
> s / content free bollocks / bits Natural Philosopher didn't understand /
> :-)
>
> Have you not read the relevant OfCom/BBC documents yet? No sign in your
> response that you have.
>

Yes. Nothing very exciting. A few people will be affected if they are
very close to a base station. Most will be curable by adding a decent
filter to the front end of the TV tuner or replacing the TV tuner with a
better one that has such built in.

Storm in a teacup really.



> Slainte,
>
> Jim

[The Natural Philosopher]

On 18/11/12 09:42, Jim Lesurf wrote:
> As with all this, the devil will be in the details.

The first correct thing you have said.

In other words interference will be very much the exception, not the rule.

I have suffered until they upped the power levels on my local TV
transmitter from sporadic interference from continental TV transmitters.

They have adjusted power and frequency levels and now all is sweetness
and light.

It will be the same here. One wonders if the 4G phones will be equally
susceptible to interference from nearby TV transmitters :-)

[Jim Lesurf]

In article <71fha8pb577qrvamo...@4ax.com>,

<ne...@address.invalid> wrote:
> On Sun, 18 Nov 2012 09:39:38 +0000 (GMT), Jim Lesurf
> <no...@audiomisc.co.uk> wrote:

> >In article <k88vsd$hv1$2...@news.albasani.net>, The Natural Philosopher
> ><t...@invalid.invalid> wrote:

[big snip]

> >Have you not read the relevant OfCom/BBC documents yet? No sign in your
> >response that you have.
> >
> I could understand that he comes to the wrong conclusion due to lack of
> or incorrect technical knowledge. No problem there. But on a purely
> logical level does he really believe that the network operators would
> choose to run their base transmitters at grossly excessive powers,
> regardless of the equipment and energy costs this would entail?

My impression thus far is that he hasn't read the documents and assumes the
kinds of EIRP levels I've quoted can't possibly be correct. There also
seems to be a tendency to assume that the link gain equation being
symmetric means the powers must be the same either way. Which implicity
assumes the same data rate and efficience. OK as a taken-for-granted for
conventional phone calls, but not for 4G.

The POV of 4G providers seem to expect to get their income from users
'consuming' things like high-quality video to their mobile device. So they
are planning for high downlink rates to lots of people. But lower rates for
uplinks. 4G isn't really for phone calls so far as the companies or OfCom
are concerned. It is for data 'consumption'. Asymmetric power requirements
from Shannon's Law thus follow.

BTW having read the latest documents about 2018, etc, I'm starting to
wonder about the long term and if that will really be thought through given
the current situation.

At present for 4G they are planning to allow up to 61dBm/5MHz for just six
channels. That already means high fields, say, 500 meters away. But what
might happen if they extend that to much more of the UHF band? How large
might the typical field exposure be in homes, and at what level does it
start having a real impact in ways *other* than pre-800MHz clearance TV
RXs? In principle, if they cleared, say, another 100 MHz they could have
another 10 downlinks (assuming as much space for added uplinks). Given the
assumption that we all need more data year-by-year, maybe also increasing
the EIRP power spectral density as well!

Far too soon to even guess about the outcome after 2018. But I've been
asking what tests or assessments on non-TV kit have been done for the
current 4G changes. Without any responses thus far...

[The Natural Philosopher]

No, but it would be a blessing if they were. :-)

But no,. that's the whole point. Its in no one's interest if TV doesn't
work with mobile 'phones'.

If the TV transmitters destroy the phones or the phones destroy the
reception on TV its not going to be acceptable.

The stupidity is that the court-holders here don't actually realise that.

[The Natural Philosopher]

Exactly.

And does he really believe that a service in which TVS and mobile
decides are splattering each other is a commercially viable one?

[Woody]

>> I seem to remember that TACS used about 25 watts per channel,
>> at the
>> base stations. That was for a low speed channel with
>> symmetric rates.
> That's about what I would expect running on 20-30 spread
> spectrum channels simultaneously. Not for a single one.
> At least 1000 times less (60dB) than the meanest TV
> transmitter.
>
> In reality you would need to be at least 40dB up on that, so
> make that 100dB ratio in terms of distance
>
>

Er, 'scuse please.

1000 times = 60dB?

Yes in voltage, but only 30dB in power.

[Jim Lesurf]

In article <k8ak2c$d5b$1...@news.albasani.net>, The Natural Philosopher

<t...@invalid.invalid> wrote:
> On 18/11/12 09:39, Jim Lesurf wrote:
> > In article <k88vsd$hv1$2...@news.albasani.net>, The Natural Philosopher
> > <t...@invalid.invalid> wrote:
> >> On 17/11/12 11:15, Jim Lesurf wrote:
> >>> In article
> >>>
> >>>
> >>> 1) That the new 4G transmissions will be so powerful that they
> >>> simply swamp or overload 'Freeview' receivers. So a user gets no
> >>> 'Freeview' TV at all, regardless of the actual frequencies of the TV
> >>> broadcasts in their area.
> >>>
> >
> >> what is the point of making them Megawatt level when what they
> >> connect to has at best a 1W device in it to reply with?
> >
> > In general terms, two reasons:
> >
> > 1) The system is intended to be used in an asymmetric manner. High
> > rates for the downlink so people can do things like watch good quality
> > video. Much lower rates for the uplink as that is mainly for command
> > and control or sending lower rate audio or video.
> >

> You know as little about RF as about IP protocols it seeems.

Impressive technical argument. Is your Dad also bigger than my Dad? Or were
you saving that argument for later? :-)

Have you read the relevant OfCom/BBC documents yet? I can't see any sign of
it in your attempts to argue about this? (inc what you wrote below)

[snip]

> > Apply Shannon's Law and you find that the 4G bases end up wanting such
> > high EIRPs.

> Er no. Not really.
> >

> > Have you not read the relevant OfCom/BBC documents yet? No sign in
> > your response that you have.
> >

> Yes. Nothing very exciting.

Ah! So you will have found the statments about the proposed 4G EIRPs
bidders can request, and that they are about 40dB different for the base
and user-mobile? Which specific OfCom/BBC documents have you read on this?
I'm wondering how you explain their EIRP figures, and why you think the
companies don't know how to apply Shannon's Equation. :-)

TBH there doesn't seem to be too much point my trying to repeatedly explain
this to you until your replies show your've read *and understood* the
documents, and are willing to think about this rather than trot out
playground ploys like "piss off". The OfCom and BBC documents are where the
figures like the EIRPs come from. So telling me to "piss off" or employ
detailed technical arguments like "Nothing very exciting" don't really get
us very far. Although it is quite amusing, I admit. ;->

[David Woolley]

The Natural Philosopher wrote:
>
> In order to GET a signal - ANY signal no matter how little data it
> containsl - to a receicver, you have to have enough peak power to
> overcome the noise.

For Gaussian noise, that is impossible. (Peak powers of gaussian noise
are unconstrained.)

>
> peak power is what screws up TV, not average radiated power.

Digital systems operate with rather low peak to mean ratios.

>
>> 2) Each phone has only one uplink user. The base station has to cater for
>> many downlink users 'symultaneously'.
>>
>
> That simply means its using its peak power more often to transmit the
> packets. Not that the peak power is increased.

I don't know the technical details of the system, but, whilst this may
be true of GSM, it isn't true of CDMA and I would be surprised if it
were true of 4G, although I don't know the technical details of the
modulation etc.

One possible technique would be to use COFDM, like DTT. DTT mean powers
don't go down if the multiplex isn't fully loaded, and the peak to mean
ratio is quite small.

[Peter Duncanson]

On Sun, 18 Nov 2012 10:38:58 +0000, ne...@address.invalid wrote:

>So in a world where every man, woman and child has a mobile phone in
>their hand/pocket/handbag, you expect them all to be turned off when
>within range of a TV set or its PVR?

Also, how does someone in a flat or non-detached house know whether or
not their mobile phone is interfering with TV reception next door? And
vice versa, how does someone know whether or not the interference with
their TV is being caused by a neighbour's mobile phone?

[Jim Lesurf]

This has already been covered in uk.tech.digital-tv. But in case people
using other usenet groups have been having difficulty finding relevant
OfCom and BBC documents I've temporarily put a basic 'starter pack' at

http://jcgl.orpheusweb.co.uk/temp/dttv.html

That page provides some links to documents.

These give various basic figures, etc, for the 4G sell-off in the New Year.
You can find additional material via the links in some of the pdfs linked
to the above page. So will be able to explore beyond them as far as your
head can stand. :-)

Note that the measurements were done by Mark Waddell of BBC R&D. But the
only public report of that at present is the slideshow for his
presentation. So I've provided a temporary link copy to that. I've
discussed the measurements with Mark. He has actually measured the impact
on many more RXs that shown in the slides. But he chose a typical data set
to avoid his plots of results becoming too full of plots to be readable!

Pages 13 and 14 of his report show the kinds of cases he considered. From
his models of the DTTV RX antennas the distances chosen/shown are the ones
that gave the highest 4G interferer link gain into the TV RX.

I'll remove the above after a day or two as they take up a few megs of
space, and the documents are all findable elsewhere anyway. There are quite
a few other documents that give details. The letter to Maria Miller (see
the page) is also well worth study.

Enjoy. :-)

[tim.....]

"CJB" <chris...@gmail.com> wrote in message
news:757ccee3-7168-4c92...@l18g2000vbv.googlegroups.com...
> Is this really an issue - that many (all?) Freeview Channels will
> suffer from severe interference with the new frequencies allocated to
> 4G mobile services?
>
> I hear that millions of Londoners will be especially affected if
> receiving Freeview from Crystal Palace transmitters / masts.
>
> This is crazy. I thought that analogue t.v. was switched off to
> provide frequencies for 4G,

No

It was switched off to enable the signal strength on DTTV to be turned up.

It was also turned off to save the costs of supporting it.

It just happens that now analogue TV has gone there are a few spare channels
available to be sold which may, or may not, be bought up by telcos to use
for 4G services.

> but it seems that Freeview frequencies are
> to be allocated to 4G as well!!
>
> I also heard that compensation will be made of £10K per household
> affected. But isn't it illegal to deliberately affect t.v. / radio
> reception, which apparently the 4G telcos will be doing.

They are doing under a government mandate so if it is illegal then HMG can
just change the rules.

[tim.....]

"David Woolley" <da...@ex.djwhome.demon.invalid> wrote in message
news:k883nu$ng$1...@dont-email.me...

> Jim Lesurf wrote:
>
>>
>> 1) That the new 4G transmissions will be so powerful that they simply
>> swamp
>> or overload 'Freeview' receivers. So a user gets no 'Freeview' TV at all,
>> regardless of the actual frequencies of the TV broadcasts in their area.
>

> I suspect in a lot of cases, only one or two multiplexes will be affected
> and only in certain weather conditions, probably without total loss of
> signal. Many people will grin and bear it, without understanding the
> nature of the problem.

The problem with "some loss of signal" with DTTV is that the result is
completely unwatchable. There is no possibly of putting up with a grainy
picture like with analogue. You either have a good picture or you don't.

tim

[Jim Lesurf]

In article <3hrha898cf1v42erk...@4ax.com>, Peter Duncanson

Generalise that to how someone will know their TV has stopped working
because a base station location a few hundred metres away has now started
emitting 4G signals.

The OfCom answer to all such questions seems to be "MitCo will know and
give you their magic oofle dust... erm filter.".

The reality, though, may be a telephone call leading to the classic
response, "You need Sky, gov" (or the equivalent in the relevant local
dialect.).

From the people who gave us computer connections via domestic mains wiring.
You know it makes sense. :-)

Slainte,

[David Woolley]

tim..... wrote:

>
> The problem with "some loss of signal" with DTTV is that the result is
> completely unwatchable. There is no possibly of putting up with a
> grainy picture like with analogue. You either have a good picture or
> you don't.
>

Most of the DTT reception problems I have cause occasional pixellation,
rather than continuous loss of signal. Whilst it is true that the
degrade is much faster than analogue, it is also true that reception
quality varies, such that degradation shows in terms of errored seconds,
rather than as all or nothing.

[Mark Carver]

tim..... wrote:

>> This is crazy. I thought that analogue t.v. was switched off to
>> provide frequencies for 4G,
>
> No

Err, Yes really. That was the game plan, called Digital Dividend. 112 MHz
worth of spectrum was to be sold off, at the time (year 2003) it was undecided
what for. Some of that (UHF Ch 61 to 69 aka 800 MHz) has been now allocated to
to LTE/4G.

http://stakeholders.ofcom.org.uk/binaries/consultations/800mhz/summary/800mhz.pdf

The remaining block (UHF Ch 31-38 aka 600 MHz) remains unused and unallocated
to date (since DSO). It might get used for broadcasting again, it might not.
One idea is if the 700 MHz band (UHF Ch 48-60) does get utilised for non
broadcast use, the 600 MHz band could be a replacement, though it's a lower
amount of capacity of course.


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

www.paras.org.uk

[ne...@address.invalid]

<smile>

[tim.....]

"Mark Carver" <mark....@invalid.invalid> wrote in message
news:agsd9l...@mid.individual.net...

> tim..... wrote:
>
>>> This is crazy. I thought that analogue t.v. was switched off to
>>> provide frequencies for 4G,
>>
>> No
>
> Err, Yes really. That was the game plan, called Digital Dividend. 112 MHz
> worth of spectrum was to be sold off, at the time (year 2003) it was
> undecided what for.

so you admit that it wasn't cleared for 4G then

which is what I said

tim

[Mark Carver]

Some of the UHF band has been cleared, and 4G will be using some of that
space. It was always the intention (and has been for 10 years or more) to sell
off liberated frequencies.

Your statement,

Quote:-

"It just happens that now analogue TV has gone there are a few spare channels
available to be sold which may, or may not, be bought up by telcos to use for
4G services. "

End Quote

Implies the decision to sell was a recent one, (which it isn't). O2 and
Vodafone have bought the space, (800 MHz) and will be using it from next
summer, no 'may' about it.

[Woody]

I just can't seem to get 'Y2K' out of my mind.

I wonder why?

[Bill Wright]

Jim Lesurf wrote:

> It is perhaps also worth bearing in mind that one of the points of high
> power 'main' TXs is to serve a larger area. Which results in those far from
> the TV TX getting a low field strength compared to people nearer the TX. So
> although served by a 'high power TV TX' they may also get problems from a
> nearby 4G base station. As with all this, the devil will be in the details.

It's almost self-evident that installers will use a transmitter if the
field strength is good enough, irrespective of whether the tx site is
near or far. This assumes of course that no other tx provides better
signals. The main stations have very large areas where the field
strength they provide is just about adequate. These areas are either on
the edges of the coverage area or they might be quite close to the tx
but screened from it. Within these areas of generally low field strength
there are great variations due to local topography, trees, and
buildings. It is in these areas of low TV field strength the the 4G
problems can be expected to arise, and because they will be as much a
function of TV field strength as 4G field strength they will crop up in
odd patches that will not immediately demonstrate to the public that the
cellphone mast is to blame.
It's a fact that low-lying areas where there's significant population
tend to have a cellphone base somewhere in the middle, not always on
high ground; in fact often low down and serving only the surrounding low
ground. These masts are often close to residential areas.
Another issue here is that these areas sometimes have the additional
problem of CCI. This might be more-or-less constant or it might
fluctuate with weather conditions. In any case it worsens BER and makes
reception more likely to be tipped over the digital cliff. A masthead
amplifier driven just slightly into non-linearity might have a
disproportionate effect under those circumstances.
There's much scope for the misapportionment of blame here. Someone whose
reception fails when a motorbike goes past will blame the motorbike,
even though their reception system has been pushed to the cliff edge by 4G.
All of this applies to reception from local relays, except that the
patches of poor field strength are much smaller.

Bill

[Bill Wright]

Peter Duncanson wrote:

> 1. I did not post that message via a mobile phone.
> 2. I have a very basic mobile phone but I use it very rarely.
>
> If my brain is fried there must be some other explanation.
>

You need oil to fry, yet the cerebrospinal fluid is mostly water. I
think 'boiled' would be more accurate.

Bill

[Bill Wright]

The Natural Philosopher wrote:

> Yes. Nothing very exciting. A few people will be affected if they are
> very close to a base station. Most will be curable by adding a decent
> filter to the front end of the TV tuner or replacing the TV tuner with a
> better one that has such built in.

Could you point me to a filter that has a reasonably flat response and
negligible loss across 470 to 789.850MHz and has 40dB of attenuation
from 790.00MHz upwards? If so, how much does it cost?

Bill

[Bill Wright]

The Natural Philosopher wrote:
> On 18/11/12 09:42, Jim Lesurf wrote:
>> As with all this, the devil will be in the details.
>
> The first correct thing you have said.
>
> In other words interference will be very much the exception, not the rule.
>
> I have suffered until they upped the power levels on my local TV
> transmitter from sporadic interference from continental TV transmitters.
>
> They have adjusted power and frequency levels and now all is sweetness
> and light.

This raises an interesting point. In the past TV transmissions have been
planned with more than just field strength in mind. For instance, some
sites have been built specifically because of CCI or multipath.
Will Arquiva respond to 4G by upping the tx powers? Personally I doubt it.

Bill

[Steve Terry]

The Natural Philosopher wrote:
> On 17/11/12 03:22, Steve Terry wrote:
>> CJB wrote:
>> Seriously i can't suggest that UHF Terrestrial TV is viable anymore.
>> Get a Dish if you can see 28e, and tell all you can to do the same.
>>
>> Interference free UHF TV is dead.
>
> Not true.
> Unless there is a 4g mast directly between you and the TV transmitter
> its unlikely you will be affected and the TVs are transmitting at
> 100kW or so, The 4G at a few watts only.
>
> There is no point in making the phone transmitters much more powerful
> since they are 2 way stations and your 4G phone wont do more than a
> watt if that.
>
You seem to have completely forgot that you, your neighbours,
and people walking by will all be using phones on 4g. Many within
50 feet or less of your TV.
Interference from 4g handhelds will be completely random and unpredictable

Steve Terry
--
Get a free GiffGaff PAYG Sim and �5 bonus after activation at:
http://giffgaff.com/orders/affiliate/gfourwwk

[Andy Champ]

On 18/11/2012 13:53, David Woolley wrote:
> The Natural Philosopher wrote:
>>
>> In order to GET a signal - ANY signal no matter how little data it
>> containsl - to a receicver, you have to have enough peak power to
>> overcome the noise.
>
> For Gaussian noise, that is impossible. (Peak powers of gaussian noise
> are unconstrained.)

Ermmm... won't the error correction deal with the odd dropped bit? (I
write as a SW engineer with only limited RF knowledge)

Andy

[Woody]

"Bill Wright" <bi...@invalid.com> wrote in message
news:k8bd5o$ga3$1...@speranza.aioe.org...

A bit tight that, but after a fashion it can be done.

I have a paging customer with a private paging system in the
153MHz general paging band. They suffer horrendous RFI from
another national paging organisation 50KHz away when their Tx's
overheat and go a tad dirty.

We got some crystal filters made in the States - last order was
$240 apiece for a dozen - but they are 40dB down on one side
50KHz away and 60dB or more down on the other side 200KHz away.
Only downside is 6dB insertion loss. They are about 3" long and
1" sq with a BNC on each end.

So yes it can be done - at a price.

[Steve Terry]

Percy wrote:
> On Sat, 17 Nov 2012, "Steve Terry" writ:
>
>> CJB wrote:
<snip>
>> IMHO It would have been fairer to have shut down UHF terrestrial
>> TV and supply all with Astra 2 dishes. Of course not all have a
>> clear path to the south east. ;-(
>
> What happens when a huge meteor shower or solar flare wipes out the
> Astra satellites?
>
> You'll be glad of a UHF service to fall back on.
>
Assuming meteor or solar flares don't affect broadband, there's IPTV
to fall back on.

[Steve Terry]

Woody wrote:
> I just can't seem to get 'Y2K' out of my mind.
> I wonder why?
>

I'm wondering why you're comparing Oranges with Apples?

There's not a single analogy with Y2K and randomly transmitting
on 700 to 800MHz affecting UHF TV

[David Woolley]

It will do so, but it doesn't rely on peak power exceeding the noise.
Shannon's law says that if you have a perfect coding scheme, aren't in a
hurry to get the decoded signal out, and the noise is Gaussian, you can
get zero error rates as long as the signal to noise ratio exceeds a
certain value for the bandwidth.

You actually get better throughput by spreading the power out thinly in
frequency and having a signal power density that is less than the noise
power density. This is one of the advantages of direct sequence spread
spectrum, as used in CDMA (3G) systems.

Although no coding system is this perfect (and people are not prepared
to wait the infinite time for a perfect system to work), error
correction does get closer to the Shannon limit.

[Andy Champ]

On 16/11/2012 22:56, CJB wrote:
> I also heard that compensation will be made of £10K per household
> affected. But isn't it illegal to deliberately affect t.v. / radio
> reception, which apparently the 4G telcos will be doing.

Give me ten grand and I'll happily let you block all my DTV signals.

Andy

[Bill Wright]

Woody wrote:


> We got some crystal filters made in the States - last order was
> $240 apiece for a dozen - but they are 40dB down on one side
> 50KHz away and 60dB or more down on the other side 200KHz away.
> Only downside is 6dB insertion loss. They are about 3" long and
> 1" sq with a BNC on each end.
>
> So yes it can be done - at a price.

Yes, and see my later post about the final solution.

Bill

[Jim Lesurf]

In article <c-CdnVSJtMix2DTN...@eclipse.net.uk>, Andy
Champ

Simple answer: Usually, yes, given a reasonable CNR.

Longer answer: Devil in details. Whatever the signal level, with 'normal'
(i.e. Gaussian) background noise there is always a non-zero chance of
errors. And a smaller but also non-zero chance they won't be corrected by
the correction schemes. Just that with a reasonably high *average* CNR the
chance of uncorrected errors is small enough not to be a bother.

So Natural Philanderer's comments about peaks are really just a diversion
here. Baloney Baffles Brains. :-)

[Jim Lesurf]

In article <k8bmjp$vl5$1...@dont-email.me>, David Woolley

<da...@ex.djwhome.demon.invalid> wrote:
> Andy Champ wrote:
> > On 18/11/2012 13:53, David Woolley wrote:
> >> The Natural Philosopher wrote:
> >>>
> >>> In order to GET a signal - ANY signal no matter how little data it
> >>> containsl - to a receicver, you have to have enough peak power to
> >>> overcome the noise.
> >>
> >> For Gaussian noise, that is impossible. (Peak powers of gaussian
> >> noise are unconstrained.)
> >
> > Ermmm... won't the error correction deal with the odd dropped bit? (I
> > write as a SW engineer with only limited RF knowledge)

> It will do so, but it doesn't rely on peak power exceeding the noise.
> Shannon's law says that if you have a perfect coding scheme, aren't in a
> hurry to get the decoded signal out, and the noise is Gaussian, you can
> get zero error rates as long as the signal to noise ratio exceeds a
> certain value for the bandwidth.

Yes. In fact you can derive Shannon's equation by using either peaks or
averages during the mathematical arguments. The nominal info rate limit
comes out the same. Just that in general people use it on the basis of the
time-averaged signal and noise powers. After that, how far you fall short
of Shannon depends on your coding scheme and if the noise departs from
being 'Normal'. (e.g. ignition interference or 1/f in some cases.)

One of the mathematical results many scientists or engineers either don't
know or avoid talking about is that true 1/f noise has an average value
that rises as you take longer time-averages. (Equivalent to sending a
longer signal.) So can be a problem in some situations. The relevant
integral blows up to infinity when you do the maths. Fortunately it returns
a finite value for Gaussian white noise. :-)

[Jim Lesurf]

In article <k8caka$i9p$3...@speranza.aioe.org>, Bill Wright

<bi...@invalid.com> wrote:
> Woody wrote:


> > We got some crystal filters made in the States - last order was $240
> > apiece for a dozen - but they are 40dB down on one side 50KHz away
> > and 60dB or more down on the other side 200KHz away. Only downside is
> > 6dB insertion loss. They are about 3" long and 1" sq with a BNC on
> > each end.

FWIW The few '4G' filters I've seen measured results for are apparently
based on ceramic resonators. No idea (yet) what will end up being handed
out like sweeties, though. Not yet been able to get any responses on that.

> >
> > So yes it can be done - at a price.

> Yes, and see my later post about the final solution.

Crumbs! That's a bit drastic, even for OfCom! 8-]

[Ian Jackson]

In message <Vpcqs.399635$Bz2.2...@fx11.am4>, Woody
<harro...@ntlworld.spam.com> writes

153MHz paging systems are narrowband, so it should be relatively simple
to make high-Q bandpass and bandstop filters from readily-available
153MHz crystals (probably 5th overtone). However, for TV, what is needed
is a lowpass filter (well, passing at least down to 470MHz*) with a
vertical cliff edge at 789.850MHz, and that is a completely different
kettle of fish.
* While you're at it, you might as well roll off below 470MHz to kill
Tetra and other things. However, it's the top end which poses the real,
more-or-less insurmountable problem.
--
Ian

[tim.....]

"Mark Carver" <mark....@invalid.invalid> wrote in message

news:agsh4d...@mid.individual.net...

> tim..... wrote:
>>
>> "Mark Carver" <mark....@invalid.invalid> wrote in message
>> news:agsd9l...@mid.individual.net...
>>> tim..... wrote:
>>>
>>>>> This is crazy. I thought that analogue t.v. was switched off to
>>>>> provide frequencies for 4G,
>>>>
>>>> No
>>>
>>> Err, Yes really. That was the game plan, called Digital Dividend. 112
>>> MHz worth of spectrum was to be sold off, at the time (year 2003) it was
>>> undecided what for.
>>
>> so you admit that it wasn't cleared for 4G then
>>
>> which is what I said
>
> Some of the UHF band has been cleared, and 4G will be using some of that
> space. It was always the intention (and has been for 10 years or more) to
> sell off liberated frequencies.
>
> Your statement,
>
> Quote:-
>
> "It just happens that now analogue TV has gone there are a few spare
> channels available to be sold which may, or may not, be bought up by
> telcos to use for 4G services. "
>
> End Quote
>
> Implies the decision to sell was a recent one, (which it isn't).

I don't agree that it implies that, because I did know that it always was
the intention to sell off spare channels

> O2 and Vodafone have bought the space, (800 MHz) and will be using it from
> next summer, no 'may' about it.

OK, I didn't know that they had actually found a buyer. I've been out of
mobile comms for 5 years.

tim

[Tim+]

"Steve Terry" <gfou...@tesco.net> wrote:
> Woody wrote:
>> I just can't seem to get 'Y2K' out of my mind.
>> I wonder why?
>>
> I'm wondering why you're comparing Oranges with Apples?
>
> There's not a single analogy with Y2K and randomly transmitting
> on 700 to 800MHz affecting UHF TV
>
> Steve Terry

I think he was referring to the pre-Y2K hysteria and how, at the end of the
day, the impact was minimal.

Tim

[Roy Brown]

In message <k88vsd$hv1$2...@news.albasani.net>, The Natural Philosopher
<t...@invalid.invalid> writing at 21:34:09 in his/her local time opines:-

>what is the point of making them Megawatt level when what they connect
>to has at best a 1W device in it to reply with?

Quite right! It's well known that a mobile phone mast can only talk to
one subscriber at a time, and that always in a predetermined direction.

Isn't it?
--
Roy Brown 'Have nothing in your houses that you do not know to be
Kelmscott Ltd useful, or believe to be beautiful' William Morris

[tony sayer]

In article <agq6jn...@mid.individual.net>, Mark Carver
<mark....@invalid.invalid> scribeth thus
>Peter Duncanson wrote:
>
>> However, TV is probably the main means of informing the population about
>> catastrophes whether local or national.
>
>Like it or not, 'Social Media' via smartphones is rapidly taking over from TV
>and radio broadcasting for that function.

Indeed it is. Our offspring hardly know how to switch the main TV on
preferring to watch and now listen to most everything on their ipads or
phones via the wi-fi!...


>
>There was a major fire near here a couple of of years ago, You Tube etc filled
>up with videos of it almost within minutes, several hours before BBC South and
>ITV Meridian broadcast the news; oh, and guess where they lifted the pictures
>from ?
>

Lorra wannabee freelancers around nowadays;!...

--
Tony Sayer

[tony sayer]

In article <hzTps.303580$Wc4.1...@fx10.am4>, Woody
<harro...@ntlworld.spam.com> scribeth thus
>[snip]

>>
>> what is the point of making them Megawatt level when what they
>> connect to has at best a 1W device in it to reply with?
>>

>[snip]
>
>It is called reciprocity and is something that is being heartily
>ignored in this thread.
>
>Because a site is licenced for 32dBW (about 1200W) it does not
>mean it has to use anything like that!
>

Indeed that is or would normally be the case but this 4G system AFAIK is
rather more akin to ADSL in operation. I haven't got aroundtuit to
reading up on it that much as yet. Suppose I must wade 'thru the Ofcom
website maze/abyss sometime!...

>
>
>

--
Tony Sayer

[John Legon]

Ian Jackson wrote:
>> "Bill Wright" <bi...@invalid.com> wrote in message
>> news:k8bd5o$ga3$1...@speranza.aioe.org...

>>> Could you point me to a filter that has a reasonably flat
>>> response and negligible loss across 470 to 789.850MHz and has
>>> 40dB of attenuation from 790.00MHz upwards? If so, how much
>>> does it cost?

> * While you're at it, you might as well roll off below 470MHz to kill
> Tetra and other things. However, it's the top end which poses the real,
> more-or-less insurmountable problem.

I assume that we've all seen the filter prototype and response curve as
illustrated in figures 1 and 3 of this document? :

http://stakeholders.ofcom.org.uk/binaries/consultations/949731/annexes/era.pdf

[Jim Lesurf]

In article <ZMudnXKDxMFLyzfN...@brightview.co.uk>, John
Legon

<jo...@nospam.demon.co.uk> wrote:


> I assume that we've all seen the filter prototype and response curve as
> illustrated in figures 1 and 3 of this document? :

> http://stakeholders.ofcom.org.uk/binaries/consultations/949731/annexes/era.pdf

I think they are the filters Mark Waddell used. But I'll check.

[Mark Carver]

tony sayer wrote:

>> Like it or not, 'Social Media' via smartphones is rapidly taking over from TV
>> and radio broadcasting for that function.
>
> Indeed it is. Our offspring hardly know how to switch the main TV on
> preferring to watch and now listen to most everything on their ipads or
> phones via the wi-fi!...

Yep, same here with our early twenties offspring. Why use their PVRs, when
they can help soak up my 100GB/Month internet allowance on i-player !

>> There was a major fire near here a couple of of years ago, You Tube etc filled
>> up with videos of it almost within minutes, several hours before BBC South and
>> ITV Meridian broadcast the news; oh, and guess where they lifted the pictures
>>from ?
>
> Lorra wannabee freelancers around nowadays;!...

Yep, loads it seems, all in the right place, at the right time !

http://www.youtube.com/watch?v=TjFZpkGJliU


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

www.paras.org.uk

[Jim]

On Fri, 16 Nov 2012 14:56:46 -0800 (PST), CJB <chris...@gmail.com> wrote:

>Is this really an issue - that many (all?) Freeview Channels will
>suffer from severe interference with the new frequencies allocated to
>4G mobile services?
>
>I hear that millions of Londoners will be especially affected if
>receiving Freeview from Crystal Palace transmitters / masts.

That it should happen to them pleases me greatly !

>This is crazy. I thought that analogue t.v. was switched off to

>provide frequencies for 4G, but it seems that Freeview frequencies are
>to be allocated to 4G as well!

Freeview uses the same spectrum as analogue used to, just uses it
differently.

Wasn't it the guard-bands between channels that were to be used? Or
perhaps they'll use all of the Freeview spectrum in areas where it isn't
being used. Different areas use different channels.

>I also heard that compensation will be made of £10K per household
>affected. But isn't it illegal to deliberately affect t.v. / radio
>reception, which apparently the 4G telcos will be doing.

Where money's involved, nothing is illegal and if it is it can
quickly be made legal.

[tony sayer]

>>A bit tight that, but after a fashion it can be done.
>>
>>I have a paging customer with a private paging system in the
>>153MHz general paging band. They suffer horrendous RFI from
>>another national paging organisation 50KHz away when their Tx's
>>overheat and go a tad dirty.
>>
>>We got some crystal filters made in the States - last order was
>>$240 apiece for a dozen - but they are 40dB down on one side
>>50KHz away and 60dB or more down on the other side 200KHz away.
>>Only downside is 6dB insertion loss. They are about 3" long and
>>1" sq with a BNC on each end.
>>
>>So yes it can be done - at a price.
>>
>153MHz paging systems are narrowband, so it should be relatively simple
>to make high-Q bandpass and bandstop filters from readily-available
>153MHz crystals (probably 5th overtone).

Well they should able to cope with that sort of channel spacing PMR
equipment does. What shouldn't happen is another TX go out of params
that much and be left like that!...

>However, for TV, what is needed
>is a lowpass filter (well, passing at least down to 470MHz*) with a
>vertical cliff edge at 789.850MHz, and that is a completely different
>kettle of fish.
>* While you're at it, you might as well roll off below 470MHz to kill
>Tetra and other things. However, it's the top end which poses the real,
>more-or-less insurmountable problem.

--

Tony Sayer

[tony sayer]

In article <agv9hk...@mid.individual.net>, Mark Carver
<mark....@invalid.invalid> scribeth thus

Now for Basingstoke this is far more exciting news;))...

http://www.youtube.com/watch?v=XUUvvG2bHzk&feature=related
--
Tony Sayer

[Woody]

"Steve Terry" <gfou...@tesco.net> wrote in message
news:k8bkne$j3h$1...@dont-email.me...

> Woody wrote:
>> I just can't seem to get 'Y2K' out of my mind.
>> I wonder why?
>>
> I'm wondering why you're comparing Oranges with Apples?
>
> There's not a single analogy with Y2K and randomly transmitting
> on 700 to 800MHz affecting UHF TV
>

The analogy was that everyone was worried silly about Y2K and the
end of the World as we know it - and what happened. Essentially
nowt.

I have already said that my opinion puts me firmly in the
'unlikely' camp.

[Woody]

[snip]

> Well they should able to cope with that sort of channel spacing
> PMR
> equipment does. What shouldn't happen is another TX go out of
> params
> that much and be left like that!...
>
>

[snip]

When you fit a 19" rack mount Tx which has a cooling fan
protruding on the front panel, then secure the rack by closing a
door which has no ventilation at that height the thing cooks -
and what happens when a Tx (in this case 100W) cooks.........?

[alexd]

Tim+ (for it is he) wrote:

> I think he was referring to the pre-Y2K hysteria and how, at the end of
> the day, the impact was minimal.

All very well saying that now, but without the hysteria, would the
preventive work have been done?

--
<http://ale.cx/> (AIM:troffasky) (UnSoEs...@ale.cx)
21:14:12 up 5 days, 18 min, 5 users, load average: 0.52, 0.67, 0.77
Qua illic est reprehendit, illic est a vindicatum

[Roy Brown]

In message <xXwqs.654090$EF4.6...@fx23.am4>, Woody
<harro...@ntlworld.spam.com> writing at 20:49:34 in his/her local time
opines:-

>"Steve Terry" <gfou...@tesco.net> wrote in message
>news:k8bkne$j3h$1...@dont-email.me...
>> Woody wrote:
>>> I just can't seem to get 'Y2K' out of my mind.
>>> I wonder why?

>> I'm wondering why you're comparing Oranges with Apples?

>> There's not a single analogy with Y2K and randomly transmitting
>> on 700 to 800MHz affecting UHF TV

>The analogy was that everyone was worried silly about Y2K and the
>end of the World as we know it - and what happened. Essentially
>nowt.

'Essentially nowt' happened only because every live COBOL programmer in
the land, and some who had to be specially disinterred for the purpose,
spent about a year and thousands of pounds putting the CC back into the
YYMMDD dates that had been used in programs in the 60s and 70s, to save
thousands of pounds on memory and storage.

(It was popularly supposed, at the time those programs were written,
that by the year 2000 the computers themselves would be writing the
programs, and more effectively and efficiently too).

However, I see no teams beavering away on avoiding this new Armageddon,
while many teams are beavering away on bringing it about :-(

>I have already said that my opinion puts me firmly in the
>'unlikely' camp.

I'm waiting for the musical - '4G and Bust'

[tony sayer]

In article <i1xqs.755664$Ak.4...@fx24.am4>, Woody
<harro...@ntlworld.spam.com> scribeth thus

Thats an excellent example of piss poor installation;!.

Ought to be bought to the attention of Ofcom's field staff.

|When its doing what it didna oughta again....
>
>
>
>

--
Tony Sayer

[Chris Kirby]

"Woody" wrote:

>A bit tight that, but after a fashion it can be done.
>
>I have a paging customer with a private paging system in the
>153MHz general paging band. They suffer horrendous RFI from
>another national paging organisation 50KHz away when their Tx's
>overheat and go a tad dirty.
>
>We got some crystal filters made in the States - last order was
>$240 apiece for a dozen - but they are 40dB down on one side
>50KHz away and 60dB or more down on the other side 200KHz away.
>Only downside is 6dB insertion loss. They are about 3" long and
>1" sq with a BNC on each end.
>
>So yes it can be done - at a price.

1. Being "a tad dirty" implies the other organisation's transmitter
(which you said is 50kHz away) is spreading onto your customer's own
frequency. How does _any_ filter fitted to your receivers help under
these circumstances? It's at the transmitter where a filter would be
effective (or better still, a transmitter that didn't go a tad dirty
when hot!)

2. You have pagers with BNC antenna sockets?

--
Chris

[Roland Perry]

In message <k8bfec$gag$1...@dont-email.me>, at 20:11:59 on Sun, 18 Nov
2012, Steve Terry <gfou...@tesco.net> remarked:
>You seem to have completely forgot that you, your neighbours,
>and people walking by will all be using phones on 4g. Many within
>50 feet or less of your TV.

Isn't the problem people walking within a few feet of the front end of
the TV aerials? Watch out for chimney sweeps with phones!
--
Roland Perry

[Roland Perry]

In message <xXwqs.654090$EF4.6...@fx23.am4>, at 20:49:34 on Mon, 19
Nov 2012, Woody <harro...@ntlworld.spam.com> remarked:

>The analogy was that everyone was worried silly about Y2K and the
>end of the World as we know it - and what happened. Essentially
>nowt.

That's because a lot of people did a lot of work (and replaced a great
deal of equipment before they would otherwise have done).
--
Roland Perry

[ne...@address.invalid]

On Tue, 20 Nov 2012 06:42:36 +0000, Chris Kirby <g4...@yahoo.com>
wrote:

Read the thread.

[Jim Lesurf]

In article <Rc99VeHy...@perry.co.uk>, Roland Perry

I *knew* there was a reason we abandoned sending young lads up chimneys.
They would only use their mobiles up there to watch HDTV!