Digital switchover causes TV problems in Oxfordshire

In article , Terry Casey
wrote:


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.


There were at least 3 contenders for the "ring main plug". NSHEB used yet
another one. In the end the MK version won, but I suspect the bulk of the
D&S installations happened before the current standard was agreed on

--
From KT24

Using a RISC OS computer running v5.16

On Tue, 23 Feb 2010 04:28:51 -0800 (PST),
"
wrote:

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...?


With COFDM the instantaneous peak voltage can be higher than the
rating of existing cables.

Peter Duncanson wrote:
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.


I'm not sure that is true.

Find some old bakelite 13A plugs and look closely at the body and how
thin the outside wall is either side of the live and neutral pins on
some of them - just where the maximum insulation is required and also
where the maximum external physical pressure is applied by someone
removing the plug from a tight fitting socket.

The 'chunky' squarish design owes more to the position of the fuse than
anything - and MK plugs that used threaded studs rather than holes in
the pins for the conductors took up a considerable amount of real estate
inside the body.

In all probability, it was the centrally located fixing screw which
really dictated the design and it was only when moulded plugs arrived on
the scene which, don't, of course, need one, that smaller designs became
possible.

--

Terry

On Tue, 23 Feb 2010 12:17:10 +0000, Terry Casey said...
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 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...

Anyone heard of this design?

http://www.minkyu.co.uk/Site/Product/Entries/2009/4/20
_Folding_Plug_System.html

--
Mark Myers

wrote:
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

Ah but they were always available, and still are (cost a bomb though):

http://www.neweysonline.co.uk/mk-ele...mation.raction

I always wondered why they didn't make much more extensive use of
those.

charles wrote:
In article , Terry Casey
wrote:

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.


There were at least 3 contenders for the "ring main plug". NSHEB used yet
another one. In the end the MK version won, but I suspect the bulk of the
D&S installations happened before the current standard was agreed on

Do you remember the Wylex contender? They hung on for quite some time in
places.

--
Adrian

On Tue, 23 Feb 2010 13:20:36 +0000, Terry Casey
wrote:

Peter Duncanson wrote:
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.


I'm not sure that is true.

Find some old bakelite 13A plugs and look closely at the body and how
thin the outside wall is either side of the live and neutral pins on
some of them - just where the maximum insulation is required and also
where the maximum external physical pressure is applied by someone
removing the plug from a tight fitting socket.

The 'chunky' squarish design owes more to the position of the fuse than
anything - and MK plugs that used threaded studs rather than holes in
the pins for the conductors took up a considerable amount of real estate
inside the body.

In all probability, it was the centrally located fixing screw which
really dictated the design and it was only when moulded plugs arrived on
the scene which, don't, of course, need one, that smaller designs became
possible.

My memories might have been contaminated by a recent experience. I
bought a surface mounting box for a light switch. I attempted to remove
one of the knock-out sections to make a cable entry point. There was a
sharp breaking sound and I was the proud owner of a box in two pieces.
The whole of a corner had broken off. The knock-out section was still in
place.

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

Martin wrote:

Big Snip

So what has happened to the development of an EU standard for plugs and sockets?

As the Shuko plug that comes on modern moulded cord sets fits both
common versions of European socket, perhaps there isn't such a high
demand for them.

On the other hand, if the UK and Eire were to adopt such a standard,
we'd have to rip out all our ring mains and install individual radial
circuits - and I can't really see that happening.

An alternative might be to take the composite design of European plug
and redesign it to be fused but there would be a lot of danger involved
with all the non-fused connectors floating around in Europe as they
could then be plugged into UK sockets fused at 32A.

I think it is about as likely as all of Europe driving on the left (or
right) myself.

--

Terry

dswan wrote:

wrote:
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

Ah but they were always available, and still are (cost a bomb though):

http://www.neweysonline.co.uk/mk-ele...mation.raction

I always wondered why they didn't make much more extensive use of
those.

They're still available because BS standard 5A and 15A connectors are
still in use in some countries - particularly India and South Africa -
see types D & M in

http://users.telenet.be/worldstandar...city.htm#plugs

--

Terry

In article , Terry Casey
wrote:
dswan wrote:

Ah but they were always available, and still are (cost a bomb though):

http://www.neweysonline.co.uk/mk-ele...mation.raction

I always wondered why they didn't make much more extensive use of those.

They're still available because BS standard 5A and 15A connectors are
still in use in some countries - particularly India and South Africa -
see types D & M in

and they are still in use in this country in the theatre where fused plugs
would be a total menace.

--
From KT24

Using a RISC OS computer running v5.16