In article , Ian Jackson
wrote:


Of course, both the British and the Irish could have simply adopted the
European systems B and G (5.5MHz sound-vision - plus the horrendous
group delay pre-correction curve). If I remember correctly, the only
difference between systems B and G is the 7 vs 8 MHz channel spacing.
Even the VSBs are the same (0.75MHz).

The extra channel width allowed the sound to be 0.5MHz higher and thus
allowed a greater vision bandwidth. Eastern Europe had an even greater
vision bandwidth with, ISTR, 9MHz channel spacing

--
From KT24

Using a RISC OS computer running v5.16

In message , charles
writes
In article , Ian Jackson
wrote:


Of course, both the British and the Irish could have simply adopted the
European systems B and G (5.5MHz sound-vision - plus the horrendous
group delay pre-correction curve). If I remember correctly, the only
difference between systems B and G is the 7 vs 8 MHz channel spacing.
Even the VSBs are the same (0.75MHz).

The extra channel width allowed the sound to be 0.5MHz higher and thus
allowed a greater vision bandwidth.

You're not telling me that, in practice, on a domestic colour TV set,
you can really see any difference in quality between a System I picture
and a System B/G picture (are you)? Even you could, was the difference
in standards really worth the bother? [Of course, technical excellence
was not the true reason that we - and a few other countries - took the
System I route.]

Eastern Europe had an even greater
vision bandwidth with, ISTR, 9MHz channel spacing

No. Their SECAM D/K uses/used 8MHz channels (both VHF and UHF).
--
Ian

In article ,
Arny Krueger wrote:
With only 360 watts, 'quite quickly' wouldn't be how I describe it. A
3kW kettle (rare these days) does that quickly.

How long before electric kettles have switchmode power supplies?

Lots of options including charging up a local cap or battery and use it
to speed the boiling process well beyond what can be done with just
line power.

Sounds like a solution looking for a problem. ;-)

--
*Dancing is a perpendicular expression of a horizontal desire *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Clive wrote:
I think nearly all interference was caused by car ignition systems which
would have been positive going, but modern cars don't use distributors
any more so the biggest source of interference has gone anyway.

Was the dizzy more of a source than the plugs themselves?

--
* What do they call a coffee break at the Lipton Tea Company? *

Dave Plowman London SW
To e-mail, change noise into sound.

"Ian Jackson" wrote in message
...
In message , Arny Krueger
writes

"Ian Jackson" wrote in message
news
In message , Arny Krueger
writes

"Dave Plowman (News)" wrote in message
...
In article ,
Bill Wright wrote:
I used to have a 12V DC kettle and it managed to boil two cups of
water
quite quickly. It pulled about 30A!

With only 360 watts, 'quite quickly' wouldn't be how I describe it. A
3kW
kettle (rare these days) does that quickly.

How long before electric kettles have switchmode power supplies?

Lots of options including charging up a local cap or battery and use it
to
speed the boiling process well beyond what can be done with just line
power.

Just think of the amount of RF hash that could be created by a cheap,
badly-designed 3kW switchmode power supply!

OTOH, well-designed ones are becoming very common.

The existing rubbish generated by PLT, plasma TVs, arcing thermostats
etc
would pale into insignificance.

I have two power amps with ca. 2 KW switchmode power supplies. They
manage -100 dB total spurious responses, with their switchmode parts only
inches from the input terminals.

But I bet they cost a bit more than your average £15/£25 domestic kettle!

This year they do! ;-)

"Dave Plowman (News)" wrote in message
...
In article ,
Arny Krueger wrote:
With only 360 watts, 'quite quickly' wouldn't be how I describe it. A
3kW kettle (rare these days) does that quickly.

How long before electric kettles have switchmode power supplies?

Lots of options including charging up a local cap or battery and use it
to speed the boiling process well beyond what can be done with just
line power.

Sounds like a solution looking for a problem. ;-)

Now you Brits are attacking your own alleged advantages for the loop.

"Dave Plowman (News)" wrote in message
...
In article ,

Clive wrote:

I think nearly all interference was caused by car ignition systems which
would have been positive going, but modern cars don't use distributors
any more so the biggest source of interference has gone anyway.

Was the dizzy more of a source than the plugs themselves?

All other things being equal, the wires presented the largest source.

Current tech puts the coils right by the spark plugs, and typically buries
them in the heads. Thus the plug wires only see the far lower primary
voltages.

In message , Clive
writes:
[]
I think nearly all interference was caused by car ignition systems
which would have been positive going, but modern cars don't use
distributors any more so the biggest source of interference has gone
anyway.

(Won't _all_ interference be positive going, if by that you mean
stronger?)

Isn't it that interference causes ringing in overloaded circuits (or
something that rings gets amplified beyond the intended range), so that
any interference has some black and some white edges, no matter what
modulation is in use?
--
J. P. Gilliver. UMRA: 1960/1985 MB++G.5AL-IS-P--Ch++(p)Ar@T0H+Sh0!:`)DNAf

Times are bad. Children no longer obey their parents, and everyone is writing a
book. -Marcus Tullius Cicero, statesman, orator and writer (106-43 BCE)

In message , Mike Tomlinson
writes:
In article , Arny Krueger
writes

http://hostedmedia.reimanpub.com/TFH.../FH01NOV_OUTLE
T_03.jpg

The ground wires in that picture appear to be in bare copper, borne out
by the person using a multimeter with a probe resting on the ground
wire. If so, that's pretty shoddy. What's to stop it coming into
contact with the exposed hot and neutral screws on the outlet body as
the outlet is pushed back into the box?

UK wiring regulations require earth (ground) wires to be sheathed in
green and yellow sleeving where it is exposed.

I have often been puzzled by this requirement. What is the reason - just
identification of the earth wire, or something else?
--
J. P. Gilliver. UMRA: 1960/1985 MB++G.5AL-IS-P--Ch++(p)Ar@T0H+Sh0!:`)DNAf

Times are bad. Children no longer obey their parents, and everyone is writing a
book. -Marcus Tullius Cicero, statesman, orator and writer (106-43 BCE)

In message , "Dave Plowman (News)"
writes
In article ,
Clive wrote:
I think nearly all interference was caused by car ignition systems which
would have been positive going, but modern cars don't use distributors
any more so the biggest source of interference has gone anyway.
Was the dizzy more of a source than the plugs themselves?
I would have guessed so as the plugs themselves were totally enclosed at
the point of spark whereas the distributor normally had to spark across
from the rotor to the cap about four times a revolution. Plastic is
not a good shield for radio frequencies.
--
Clive