Re: Center Frequency when setting RTTY Filters
Posted by
Bill Coleman-2 on
Oct 10, 2005; 4:59am
URL: http://elecraft.85.s1.nabble.com/Center-Frequency-when-setting-RTTY-Filters-tp382766p382768.html
On Oct 9, 2005, at 2:30 PM, Jeff Stai wrote:
> You want to set it to the center of the two tones you are using for
> AFSK. If 1000Hz is your Mark frequency, and 170Hz is your shift,
> then you should center at 1000-(170/2) or 915Hz.
If you do this, don't use OP1 as your FL1 filter. The second harmonic
of your tones will be in the passband when you are transmitting,
otherwise.
I recommend higher frequencies. I ended up using 1500 Hz as the
center of my RTTY filter passband.
Bill Coleman, AA4LR, PP-ASEL Mail:
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Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901
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