Digital switchover causes TV problems in Oxfordshire

In my view that simply because there's been a total lack of imagination
when it comes to design, other than making something square and as
unnecessarily large as a house brick, one only has to look at some of the
newer molded ones, which are quite compact and are much better
ergonomically designed than their predecessors.

Should have used 110V, much safer, and those small plugs from the US (duck
down to avoid things thrown at him) ;-).

Plugging any sort of heating element, say an iron, is always amusing in the
states. The cable is "meaty" but the plugs are always warm to the touch
after not too long. And many older US houses still have "two-pin, no earth"
sockets!

Paul DS.

On 23 Feb 2010 08:30:33 GMT, (Richard Tobin)
wrote:

In article ,
Mark Carver wrote:

Ring main is a peculiarly UK system. It was invented to save on copper for
the post-war housebulding boom. Its major disadvantage is that plugs need
to be large enough to incoporate a fuse.

They could have put fuses in the sockets.

No, because the fuse is there to protect the appliance's cable, (and not as
many believe the appliance itself). So for an appliance with a thinner cable
you'd obviously need to change the fuse in the socket.

Clearly having a lower fuse for a thinner cable is better, but a fixed
fuse in the socket provides just as good protection as the fixed fuse
in a non-ring main. So the ring main does not require fuses in the
plugs.

Consider the practicalities of having a fuse in a socket. It has to be
arranged with safety in mind. It might be possible today to make a fused
socket in which the fuse is in a holder that can be withdrawn with the
opening being closed by a shutter. One could not rely on the person
changing a fuse switching off the (correct) ring main at the
distribution unit.

At the time that the ring main system was introduced the materials
available, particularly plastics, were not suitable for making a socket
with a safely removable fuse unit.

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

On Tue, 23 Feb 2010 08:11:58 GMT, "Ivan" wrote:



"charles" wrote in message
. ..
In article ,
Martin wrote:
We have three phases. Dutch wiring is peculiar. No ring mains and the bog
standard set up limits you to a total of 16 amps. To use any sort of
electric oven you have to convert to three phase.


Ring main is a peculiarly UK system. It was invented to save on copper
for
the post-war housebulding boom. Its major disadvantage is that plugs need
to be large enough to incoporate a fuse.



In my view that simply because there's been a total lack of imagination when
it comes to design, other than making something square and as unnecessarily
large as a house brick, one only has to look at some of the newer molded
ones, which are quite compact and are much better ergonomically designed
than their predecessors.

There used to be 3-pin plugs with rubber tops that were moderately
ergonomic. There have been considerable developments in plastics since
the ring main was introduced. The sort of rigid tough plastic that is
now used to make molded plugs today simply did not exist. The plastic
that originally used for plugs was relatively fragile and therefore had
to be bulky rather than thin.

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

On 22/02/2010 23:53, Brian Gregory [UK] wrote:
wrote in message
...
In ,
wrote:


wrote in message
news[email protected]
Sorry if already posted

An apology has been given to viewers in Oxfordshire who have been
experiencing problems with their TV reception.

http://news.bbc.co.uk/1/hi/england/o...re/8527928.stm

The video very interesting when they state temporary aerial half the
height and they expected it to give same coverage!

just shows how few people know anything about propagation. Transmitter
engineers (witha few exceptions) seem to think that once the signals have
gone up the mast everything will be fine.

This is utterly ludicrous.

Did the people who thought the aerial half way up the mast would give the
same coverage think the top half of the mast was just there for fun? Didn't
it occur to the that the mast might have been built that high for some good
reason?

When the calculations were done, 4 or 5 years ago, they showed the
expected losses round the edges of the service area, and a few other
areas which lost line of sight from the lower antenna. I think the
message got lost on its way up the hierarchy (as it usually does).
Also, the problem with a lot of installed aerials is that they only have
just enough gain to produce an acceptable picture on analogue. If the
analogue transmitter goes to reduced power, all that happens is you get
a noisy picture, with digital, it disappears.

Phil

charles wrote:
In article ,
Martin wrote:
We have three phases. Dutch wiring is peculiar. No ring mains and the bog
standard set up limits you to a total of 16 amps. To use any sort of
electric oven you have to convert to three phase.


Ring main is a peculiarly UK system. It was invented to save on copper for
the post-war housebulding boom. Its major disadvantage is that plugs need
to be large enough to incoporate a fuse.


They don't have to be that large. In fact, some modern moulded cord sets
have 13A plugs with a very small form factor.

My (German designed) SatNav PSU has interchangeable pins and the 13A bit
is very small - there just isn't all that wasted space round the outside.

Try drawing the pin arrangement full scale, then placing a close fitting
circle round them and you'll be surprised how small the plug COULD be...

--

Terry

charles wrote:
In article , Richard Tobin
wrote:
In article , charles
wrote:
Ring main is a peculiarly UK system. It was invented to save on copper
for the post-war housebulding boom. Its major disadvantage is that
plugs need to be large enough to incoporate a fuse.

They could have put fuses in the sockets.

but they didn't


Never seen a fused spur? (OK, I know it's not a socket, but it could
have been ...

--

Terry

In article ,
Peter Duncanson wrote:


Consider the practicalities of having a fuse in a socket. It has to be
arranged with safety in mind. It might be possible today to make a fused
socket in which the fuse is in a holder that can be withdrawn with the
opening being closed by a shutter. One could not rely on the person
changing a fuse switching off the (correct) ring main at the
distribution unit.

At the time that the ring main system was introduced the materials
available, particularly plastics, were not suitable for making a socket
with a safely removable fuse unit.

Ring mains have always had "fused spur" units.

--
From KT24

Using a RISC OS computer running v5.16

On 22 Feb, 17:26, madge wrote:
Sorry if already posted

An apology has been given to viewers in Oxfordshire who have been *
experiencing problems with their TV reception.

http://news.bbc.co.uk/1/hi/england/o...re/8527928.stm

The guy bought a new STB, new aerial, new booster, and a satellite
dish for under £100? Bargain!

He didn't appear to have bought a DSat STB (or even an LNB!) so I
wonder what he was going to do with the dish?!


Why do so many transmission aerials need replacing? Aren't post-switch-
over digital signals still at a lower power than the original analogue
ones? Or are the power values misleading? Or is it 6 muxes vs 4/5
channels? Or...?

Cheers,
David.

Martin wrote:
On Mon, 22 Feb 2010 22:55:07 +0000 (GMT), charles
wrote:

In article ,
Martin wrote:
We have three phases. Dutch wiring is peculiar. No ring mains and the bog
standard set up limits you to a total of 16 amps. To use any sort of
electric oven you have to convert to three phase.

Ring main is a peculiarly UK system. It was invented to save on copper for
the post-war housebulding boom. Its major disadvantage is that plugs need
to be large enough to incoporate a fuse.

Fused plugs and sockets that small dogs cant pee into and children can't poke
bits of wire into are advantages. On a Dutch plug the live and neutral pins are
interchangeable.

Not just restricted to the Netherlands. There are two versions of the
common continental plug/socket which are the same size.

The French version, also adopted by Belgium, has the earth pin
protruding from the socket (the mating plane is recessed, so it doesn't
project beyond the face plate) and the earth socket is in the plug, so
that they will only mate one way, as in the UK.

The other, more widely version, has a side contact arrangement for
earthing so, as Martin says, the plug can mate either way round.

Continental plugs can have different pin diameters for different current
requirements, so the fixed dimension is the outside of the pin - not the
centres.

There was a problem with the French system when it was first used as an
unearthed plug would not fit an earthed socket because of the protruding
pin! (The dimensions are identical.) There were, of course, many more
un-earthed plugs in use than the new earthed type.

This was resolved by using a slim, flat, 2-pin plug rated at 6A -
especially since moulded cord sets have been available - which fits
beside the protruding earth pin. Other plugs simply have holes to
accommodate the earth pin.

--

Terry

tony sayer wrote:
In article
s.com, scribeth thus
On Feb 22, 10:55 pm, charles wrote:
In article ,
Martin wrote:

We have three phases. Dutch wiring is peculiar. No ring mains and the bog
standard set up limits you to a total of 16 amps. To use any sort of
electric oven you have to convert to three phase.
Ring main is a peculiarly UK system. It was invented to save on copper for
the post-war housebulding boom. Its major disadvantage is that plugs need
to be large enough to incoporate a fuse.

--
From KT24

Using a RISC OS computer running v5.16
But those postwar houses often had 15A sockets, and 15A plugs don't
have fuses.

Bill

Now I'd hate to disagree with the fount of all wisdom of Yorkshire but
ISTR there was one that had the live pin as a fuse.. but they were very
rare...

I'm afraid that you're wrong - and the fount of all wisdom of Yorkshire
is (W)right!

The device to which you refer was a THIRTEEN amp RING MAIN connector
manufactured by Dorman & Smith. (I'm sure it's been discussed on here in
the past year.)

They were widely used on post-war council housing estates and the
suspicion is that D&S offered the sockets to local authorities at a much
lower price than the convention MK, Crabtree, etc., 13A type, knowing
that they'd recoup any loss from the ridiculously over priced (patented)
plugs and fuses that the householders would be forced to buy afterwards.

Unfortunately, if the screw-in live pin/fuse became loose, there was a
danger of it parting company from the plug whilst it was mated with the
socket, so that it remained sticking out of the socket when the plug was
removed ...

--

Terry