[Lowfer] Billboard display - LEK

[John Andrews]

Lyle,

When I did my version, I used ten 0.1 Hz steps vertically, and 30 second
dots. The 3 letters are 15 dots wide, if memory serves. The end result
looked best with ARGO 30 second slow screens. While it worked pretty well
for TAG, my head began to hurt when I thought of coding some of the other
letters. Never went back to it...maybe this winter.

John A.

> Slowing down the modulation is easy. The timing factor is expressed as a
> 4-digit hexadecimal number in the device EEPROM, and my present setting is
> 00 A0. Lots of room for expansion there!! The frequency resolution of the
> exciter is the limiting factor. With a 12.8 MHz clock, the smallest
> frequency steps are about 0.085 Hz, and I am presently using a frequency
> shift of 4 steps between rows in the display. Reducing this to the minimum
> of 1 step, and increasing the timing factor by a factor of 4, the result
> would be approximately 30-second dots and a total bandwidth of about 0.34
> Hz. I think that's about as slow as it makes sense to go, anyway, because
of
> the QSB cycle time. The Argo settings would probably have to be something
> like QRRS60, slow mode. I'll run it that way for a while this afternoon
and
> see what the characters look like on the screen.
>
> Lyle
>
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