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uk.tech.digital-tv (Digital TV - General) (uk.tech.digital-tv) Discussion of all matters technical in origin related to the reception of digital television transmissions, be they via satellite, terrestrial or cable. Advertising is forbidden, with no exceptions.

Do LED bulbs interfere with DAB radio?



 
 
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  #11  
Old January 1st 17, 06:52 PM posted to uk.tech.digital-tv
Roderick Stewart[_3_]
external usenet poster
 
Posts: 2,159
Default Do LED bulbs interfere with DAB radio?

On Sun, 1 Jan 2017 15:32:13 -0000, "Woody"
wrote:


"Jim Lesurf" wrote in message
...
In article , Woody

wrote:

Why do manufacturers choose 'odd' colour temperatures. If they are
replacing incandescent bulbs then they need to be around 2300K to
colour match, if they are replacing halogen then they need to be a
bit
higher - somewhere around 2700-3000K. So why are Philips making a
bulb
at 4000K which is more like the colur of a daylight white
fluorescent
tube? Barmy to my mind.


The history IIRC is that the early generations of high efficiency
'white'
LEDs use(d) blue/UV LEDs along with phosphors to convert some of
that into
other wavelengths to get 'white'. The results tended to have to lean
towards the blue for efficiency reasons.

IEEE Spectrum did an article on this some time ago. One result of
the above
is that many locations adopted the new LEDs for street lighting to
save
power/money. They now realise those LEDs are uncomfortably 'blue'
and need
replacing.

Later types give lower colour temperatures. But the early ones might
be
cheaper to make at present. What I don't know is if it is still the
case
that to get the 'warmer' temperatures you still end up with lower
efficiency and/or high cost.



I have to say I would prefer SOX fittings - preferably the high
pressure lamps with the gold light - to LED any day. I don't
understand why but the 'daylight' white of LEDs doesn't seem to light
objects - especially people - in the same way that limited spectrum
lights do.

I remember as a child travelling back to Leicester from Chesterfield
having visited family and going through Derby where flourescent street
lights were the norm. It made it very difficult to see where you were
going especially if it was foggy, which suggests that colour has a
significant part to play.

I think however I may have accidently found out more about it. We have
a PIR switched lamp on our shed which has a habit of lighting up at
night for no apparent reason. To reduce consumption yesterday I
replaced the R7s 100W 78mm halogen fitting with a 20W LED reflector
unit, and I went outside last night to test it. What was immediately
obvious was that the LED lamp lit things that the light fell on but it
did not light 'around' objects in the same way that the previous flood
did. I think a lot of that is to do with the fact that the halogen
lamp worked properly in that the source was in front of the reflector
and the light was distributed: despite having what looks like a
reflector, the LEDs being behind the reflector do not actually 'use'
the reflector and thus works like a point source. Even though street
lights have a number of these point sources they still don't spread
the light in the same way and that is why I personally find them
unacceptable.

I have a R7s 118mm fitting at the front of the house in which I
replaced the halogen with a LED assembly of 6W rating. Whilst I do not
like the colour of the light emitted, as the source is in a similar
physical position to the tube that it replaced it uses the reflector
'properly' spreads the light in a much more visibly acceptable
pattern.


The difference you describe isn't really to do with the colour of the
LED lights, but the distribution. Fair comment, because they are
different and need dealing with differently, it's not a difference in
colour.

All my house lights are now LED, mostly bayonet fitting replacement
bulbs, but they do really need a different style of lampshade to work
most effectively because they don't radiate so much light towards the
connector end on account of the lump of electronics in the way. Nearly
all lampshades in the shops still seem to be of the open ended
cylinder type, presumably to allow airflow for hot bulbs, despite the
fact that not all bulbs are hot these days, so a ceiling fitting will
illuminate the area underneath it but not throw so much soft light via
the ceiling. The shades I like best for this purpose are the
upside-down "coolie" type, which don't give a direct view of the bulb
at all but throw all their light upwards onto the ceiling. They work
best with white ceilings of course.

As for colour, "warm white" around 3000K seems the most pleasing
replacement for conventional bulbs, so I avoid the ones described as
"daylight" around 6000K which give a very severe clinical look.
There's also a new one called "vintage" which is a long way below
3000K and looks like gaslight, which I suppose is the intention, but
it makes everything look very dingy. The LEDs in these "vintage" bulbs
are arranged in strips a bit like old-fashioned filaments and they've
somehow made the electronics smaller so there isn't that lump blocking
the light, which gives a much better distribution, but unfortunately
they don't seem to be available in any other colour (yet?).

Rod.
  #12  
Old January 2nd 17, 07:27 PM posted to uk.tech.digital-tv
Max Demian
external usenet poster
 
Posts: 3,836
Default Do LED bulbs interfere with DAB radio?

On Mon, 02 Jan 2017 12:21:35 +0100, Martin wrote:
On Sun, 01 Jan 2017 17:04:59 +0000 (GMT), Jim Lesurf


wrote:
On 01 Jan, wrote:


Why does it matter with street lights? No-one (effectively)

complained
about the (bluish) mercury lights or even low (yellow) and

high (pink)
pressure sodium lights.


Afraid I can't now recall the reasons given. I'll see if I can

find my
copy of that issue of 'Spectrum', although I tend to bin them

afer a few
months so this will be a matter of luck. Alteratively, the

article may
be on their website.


Found it. Issue 10.16 of IEEE Spectrum "The early adopter blues"

by Jeff
Hecht. Not re-read it, but you may be able to find the details on

the web.

The article is here

http://spectrum.ieee.org/green-tech/...etlights-are-g
iving-neighborhoods-the-blues

What moaning minnies. I've got two metres of RGB LED strip over my
living room window hooked up to a three knob dimmer so I can have any
colour I like. Maybe they could have a similar arrangement for street
lighting, radio controlled so they can adjust the colour to suit
people's tastes.

--
Max Demian
  #13  
Old January 2nd 17, 07:30 PM posted to uk.tech.digital-tv
charles[_2_]
external usenet poster
 
Posts: 622
Default Do LED bulbs interfere with DAB radio?

In article ,
Max Demian wrote:
On Mon, 02 Jan 2017 12:21:35 +0100, Martin wrote:
On Sun, 01 Jan 2017 17:04:59 +0000 (GMT), Jim Lesurf


wrote:
On 01 Jan, wrote:


Why does it matter with street lights? No-one (effectively)

complained
about the (bluish) mercury lights or even low (yellow) and

high (pink)
pressure sodium lights.

Afraid I can't now recall the reasons given. I'll see if I can

find my
copy of that issue of 'Spectrum', although I tend to bin them

afer a few
months so this will be a matter of luck. Alteratively, the

article may
be on their website.

Found it. Issue 10.16 of IEEE Spectrum "The early adopter blues"

by Jeff
Hecht. Not re-read it, but you may be able to find the details on

the web.


The article is here

http://spectrum.ieee.org/green-tech/...etlights-are-g
iving-neighborhoods-the-blues


What moaning minnies. I've got two metres of RGB LED strip over my
living room window hooked up to a three knob dimmer so I can have any
colour I like. Maybe they could have a similar arrangement for street
lighting, radio controlled so they can adjust the colour to suit
people's tastes.


or even adjust it yourself from your phone as you walk past.

--
from KT24 in Surrey, England
  #14  
Old January 3rd 17, 11:01 AM posted to uk.tech.digital-tv
Scott[_2_]
external usenet poster
 
Posts: 1,263
Default Do LED bulbs interfere with DAB radio?

On Mon, 02 Jan 2017 19:30:41 +0000 (GMT), charles
wrote:

In article ,
Max Demian wrote:
On Mon, 02 Jan 2017 12:21:35 +0100, Martin wrote:
On Sun, 01 Jan 2017 17:04:59 +0000 (GMT), Jim Lesurf


wrote:
On 01 Jan, wrote:


Why does it matter with street lights? No-one (effectively)

complained
about the (bluish) mercury lights or even low (yellow) and

high (pink)
pressure sodium lights.

Afraid I can't now recall the reasons given. I'll see if I can

find my
copy of that issue of 'Spectrum', although I tend to bin them

afer a few
months so this will be a matter of luck. Alteratively, the

article may
be on their website.

Found it. Issue 10.16 of IEEE Spectrum "The early adopter blues"

by Jeff
Hecht. Not re-read it, but you may be able to find the details on

the web.


The article is here

http://spectrum.ieee.org/green-tech/...etlights-are-g
iving-neighborhoods-the-blues


What moaning minnies. I've got two metres of RGB LED strip over my
living room window hooked up to a three knob dimmer so I can have any
colour I like. Maybe they could have a similar arrangement for street
lighting, radio controlled so they can adjust the colour to suit
people's tastes.


or even adjust it yourself from your phone as you walk past.


Or set it in the car preferences :-)
 




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