[Elecraft] RTTY Problems

[Bill Coleman]

On Mar 19, 2007, at 5:36 AM, Dohn wrote:

> If one centers their filters at 2210 Hz in RTTY mode for use in  
> RTTY, then
> is RTTY no longer the mode of choice for PSK31?  Would you just use  
> USB for
> PSK31 and adjust your speech compression?  Are RTTY and PSK31 both  
> useable
> with RTTY mode with filters centered around 2210 Hz?

PSK31 can be used at any center frequency, so 2210 Hz won't be a  
problem.

I use Cocoamodem and MMTTY for RTTY, and have adjusted them for  
frequencies of 1415 and 1585 for Mark and Space, respectively. This  
gives me a 1500 Hz center frequency, which is perfect for using the  
DSP filters as well.

One problem with using 2210 Hz as a center frequency with the K2 is  
that you may not have sufficient BFO range to center your filters for  
both sidebands. You may have to modify the BFO to get greater range.  
Having both sidebands centered is important. Even though you might  
only use the LSB sideband for RTTY, remember the sidebands are  
swapped on 15m and above due to the inversion.

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr at arrl.net
Quote: "Not within a thousand years will man ever fly!"
             -- Wilbur Wright, 1901