Why "RTTY" mode versus DigL for RTTY

Andrew O'Brien

My A.I agent says "

• Why Not Native
•  
• RTTY
•  
• Mode?
•  
• In SmartSDR, the native
•  
• RTTY
•  
• mode applies an internal IF shift specifically designed for knob-tuning the Mark/Space frequencies directly within SmartSDR's own slice filter. Third-party digital engines like SDC, MMTTY, or FLdigi expect raw, flat digital audio from the DAX stream and handle the offset calculations/audio decoding in their own software layer. Setting the slice to native
•  
• RTTY
•  
• can cause offset discrepancies or filter conflicts between the radio and SDC.

I am wondering why Flex would do this in an age where almost everyone using RTTY does so in a contest using the aforementioned third party apps . Not a big issue but I am intrigued .

Andy K3UK

Mike-VA3MW

When in RTTY, we use the RTTY filtering to focus on a single RTTY single for better signal detection. RTTY detection also leverages the fact that if the MARK or SPACE signal is not being sent, that the other half of the signal is being sent. The RTTY filtering may also be better in crowded band conditions.

When using DIGL in traditional Digital mode, you are moving the audio filtering into the sound card.

I think you'll find more RTTY operators use the traditional method but since I am not aware of a poll that actually addresses this, I am making an assumption.

Andrew O'Brien

Good explanation Mike , useful for me to be aware of .

Andy K3UK

Mike-VA3MW

And, maybe we just use the old method because watching the simulated RTTY scope is cool and we are just old. :)

That is from the days when we actually had an oscilloscope of the desk to help tune the signals.

Ken Wells

Having a separate "RTTY" Mode also lets you define a separate Mic Profile for RTTY that has specific Low-Cut and High-Cut settings set specifically for RTTY. This also creates a visible Transmit bandwidth "ribbon" in the panadapter, so that you can tell exactly where your transmit signal will be. This is especially useful when using XIT.