[Elecraft] CFL's - LEDs - Solar

[Matthew Cook]

You should find that many of these lamps will have a little known value
written on the side of the box that will help you decide.  The ]Colour
Rendering Index (CRI) of these lamps will tell you how faithfully they will
reproduce all colours of the spectrum.  If you find a lamp without this
information on the side of the box, then be careful and perhaps don't buy
it.

A CRI of greater than 90% (0.9) with a colour temp between 3000-4000 will
be adequate for the shack and reading of resistors and colour codes.  It
turns out that brown and deep reds are very difficult colour to faithfully
reproduce from blue rich white light, which isn't a new phenomenon since
long arc fluorescent, CFL and LED all derive white light the same way.  For
reference low pressure and high pressure metal halides have a CRI of 100%
which is why you find them used in art museums, ditto tungsten et al.

However pay careful attention to noise from these more modern lamps, the
EMI from some cheap and nasty LED/CFL lamps is just hideous.  We all want
to preserve the noise floor for our Elecraft RX's, just to keep this on
topic.

73

Matthew
VK5ZM


On 28 September 2015 at 04:21, Dale Putnam <daleputnam at hotmail.com> wrote:

> For those looking at CFLs or LEDs in the shack, and presuming that is
> where you built, very close attention must be given to
> the color and intensity of the light emitter. Especially if you are
> working with hole through color coded components, like resistors.
> The perceived color of the bands/dots may NOT be exactly what was
> intended, NOR what will be percieved when re-examined under direct
> sunlight. Direct sunlight is tuff to come by after sundown and prior to
> dawn, and with the longer hours of winter darkness coming, look hard and
> long at the different light emitters.
>
> a simple word to the builder, from the... now a bit wiser.
>
> Have a great day,
>
>
> --...   ...--
> Dale - WC7S in Wy
>
>
>
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