an easy way to get something close, though its a bit a of a process, would be to create the gradient in photoshop. then change the color space to index color (image>mode>index color) and select ‘web’ or ‘uniform’ for the palette and set the dither option to ‘pattern’.
you may be able to create a custom color palette (an option in the index color setting) to make it more precise to the color space you are trying to mimic.
Kevin Camp
Art Director
KCPQ, KZJO & KRCW