calculating transmissivity from transmittance

I am trying to calculate glazing transmssivity for window glass with a measured transmittance of 0.44. I have tried to use the formula on the rayfront website http://www.schorsch.com/rayfront/manual/dielectricdef.html but keep on getting a strange answer 0f -320. Does anyone know if this formula is correct or how to calculate transmissivity?

Cheers

Ben Masters

···

Get your FREE download of MSN Explorer at http://explorer.msn.com

Dear Ben,

the formular equals the formular in the tutorial and is correct. (We use
it since years and you can also check it with virtual tranmittance
measurements.)

The transmissivity value should be .479807.

Jan

ben masters wrote:

···

I am trying to calculate glazing transmssivity for window glass with
a measured transmittance of 0.44. I have tried to use the formula on
the rayfront website
http://www.schorsch.com/rayfront/manual/dielectricdef.html but keep on
getting a strange answer 0f -320. Does anyone know if this formula is
correct or how to calculate transmissivity?CheersBen Masters

-----------------------------------------------------------------------
Get your FREE download of MSN Explorer at http://explorer.msn.com
_______________________________________________ Radiance-general
mailing list [email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

--
-------------------------------------------------------------------
   o - NEW ADRESS!!!
  > \ Jan Wienold
                 Fraunhofer Institute for Solar Energy Systems
                 SOLAR BUILDING DESIGN GROUP - DAYLIGHTING
                 Heidenhofstr. 2
                 79110 Freiburg
                 GERMANY

                 Phone: ++49 - (0) 761 - 4588 -5- 133
                 Fax: ++49 - (0) 761 - 4588 -9- 133
                 Email: [email protected]

                 Internet:
                 http://www.ise.fhg.de