Loss of Freeview Channels with 4G Mobile

On 17/11/12 13:59, alexd wrote:
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.

Exactly, so switch off yer handset when watching TV.


--
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.

On 17/11/12 20:29, Peter Duncanson wrote:
On Sat, 17 Nov 2012 15:06:38 +0000, Peter Duncanson
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.


--
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.

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


--
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.

On 17/11/12 21:17, Bill Wright wrote:
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.

Sky salesmen

Bill


--
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.

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.







--
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.

On Saturday, November 17, 2012 9:34:06 PM UTC, The Natural Philosopher wrote:
On 17/11/12 11:15, Jim Lesurf wrote:

In article

,

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?



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 ********



--

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.

Well, for starters, the base station is likely to have 10 - 15 dB better receive sensitivity than the user equipment, so will need to transmit significantly more power to achieve a balanced link.

On Saturday, November 17, 2012 10:49:45 PM UTC, wrote:
On Saturday, November 17, 2012 9:34:06 PM UTC, The Natural Philosopher wrote:

On 17/11/12 11:15, Jim Lesurf wrote:



In article



,



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?







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 ********







--



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.



Well, for starters, the base station is likely to have 10 - 15 dB better receive sensitivity than the user equipment, so will need to transmit significantly more power to achieve a balanced link.

see for example:-

https://sites.google.com/site/lteenc...get-comparison

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.

In article ,
David Woolley wrote:
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.

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

On Saturday, November 17, 2012 11:05:04 PM UTC, Nick Leverton wrote:
In article ,

David Woolley wrote:

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.



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

I think the drive for more mean carrier power has mostly come from the desire to support several carriers, potentially using different radio access technologies, simultaneously on one antenna system. The maximum transmit EIRP has been 1640W for the last 20 years or so (not sure where the 6KW figure is coming from, unless the goalposts have been moved), hence there's been little point in increasing power per carrier.