[R-390] OT: LED tail lights, white LED physics

[Bob Camp]

Hi

It is absolutely amazing just how many incandescent bulbs are made per 
year all over the world. For a 125 year old technology they certainly 
are going strong. Not very many other electrical / electronic gizmos 
have those sort of legs ... (except tube based receivers of course ...)

I don't think the low wattage incandescent bulb business has much life 
in it for new applications. It will probably be kept alive by things 
like the R-390 and it's cousins that will keep burning out bulbs as 
long as people are willing to stuff them into it.

in addition to reliability the incredibly low efficiency of a Xenon 
strobe it's pretty easy to understand why the tower light replacement 
makes sense. Fluorescents have been fighting incandescents on that 
basis in home lighting for years.  Homes are still full of incandescent 
bulbs.

Strange but true - it's been say 60+ years since 28 volt generator 
based home lighting systems were an "in" thing. There are at least a 
dozen homes down south of here running 28 volt lighting. They don't 
understand R-390's and I don't understand their wiring. We have agreed 
to disagree ...

I'm betting on incandescent bulbs being with us for a while ... even 
the 28 volt versions.

	Take Care!

		Bob Camp
		KB8TQ



On Jul 7, 2004, at 9:01 PM, Dave Maples wrote:

> All: Not to mention that the replacement cycle for the LED lamps is 
> measured
> in years and years as opposed to standard incandescent bulbs.
>
> In the commercial radio business (Nextel) we are seeing more and more 
> tower
> lights move harder and harder toward LED technology.  It's way more 
> reliable
> than xenon strobes.
>
> I don't think I'd want to be in the incandescent business much longer.
> Methinks that before I die in 20-30 years it's going to be well on its 
> way
> out.
>
> Dave Maples
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net
> [mailto:r-390-bounces at mailman.qth.net]On Behalf Of Tom Norris
> Sent: Wednesday, July 07, 2004 3:23 PM
> To: R-390 at mailman.qth.net
> Subject: [R-390] OT: LED tail lights, white LED physics
>
>
> According to USDOT and such, they are supposed
> to be annoying. Apparently the instant on feature
> cuts as much as a quarter second off the response
> time that would otherwise be spent getting an
> incandescent filament lit to full brightness. A
> quarter second is a long time as accident response
> goes, and can mean the difference in avoiding an
> rear-end or sliding under the vehicle in front of you.
>
> That being said, as far as LEDs for running lights,
> the red is too "spectrally pure" and is way hard on my
> eyes too.
>
> I tend to agree on the white LEDs being somewhat
> "harsh" since they tend to have a blue shift to then.
> Indeed all should, the white leD is manufactured
> from a blue or uv led die, which is then doped with a
> mixed spectrum phosphor-like material. The effect is
> not unlike that of a florescent lamp. The harshness
> comes from the blue or uv/blue that is emitted as
> the phosphor doesn't do much to block it.
>
> Tom
>
>
>> James Miller wrote:
>>
>>>  I prefer the "soft" on and off times of filament lamps over the
>>>  instantaneous on-off of LEDs.
>>>  Ever drive behind a car with those obnoxious LED brake lights,
>>>  especially the Cadillacs?, They flash on instantly... no soft warm 
>>> up
> time.
>>>  It's grating on the nerves.
>>
>> Or new "large cars" (18 wheelers). EXTREMELY annoying....!!! We
>> just returned from a 3967 mile trip out east to visit relatives. 
>> Traffic
>> around Minneapolis was chaotic.
>>
>> Ken W7EKB
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