RTTY Frequency reducing

[richard brown]

I'm having real difficulty receiving the RTTY from my LORA rfm98 chip. I'm using CubicSDR and DL-FLDIGI. When you listen through the speakers the RTTY signal starts and immediately drops in tone, and the red line on the waterfall also drops. The LORA chip is running on a 3v3 pro mini using TBTracker. What am I doing wrong??

[David Akerman]

You will get some drift due to the device warming up once transmission is enabled, but that should soon settle.  Does TBTracker transmit continuously ?

On Wed, 24 Mar 2021 at 14:48, richard brown <bradsst...@gmail.com> wrote:

I'm having real difficulty receiving the RTTY from my LORA rfm98 chip. I'm using CubicSDR and DL-FLDIGI. When you listen through the speakers the RTTY signal starts and immediately drops in tone, and the red line on the waterfall also drops. The LORA chip is running on a 3v3 pro mini using TBTracker. What am I doing wrong??

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[richard brown]

The effect does seem to reduce with time but still after 15 mins it's still reducing. TBTracker doesn't, ive set it to repeat 3 times a minute so I can test it put on the ground but that would quickly eat my battery im sure if I left it like that!

[David Akerman]

When I've done RTTY on LoRa, I have it send 2 consecutive RTTY packets before returning to LoRa, to give the signal time to stop drifting and to give dl-fldigi a chance to lock on.  Worked for me.

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[richard brown]

thank you I'll certainly do that for the finished payload then. I can hear RTTY warbling but still nothing from DLFLDIGI. Im just starting out so will play with settings

[Mark Jessop]

While i'm not sure horus-gui will do any better than dl-fldigi, it might be worth giving its RTTY decoder a go: https://github.com/projecthorus/horus-gui#binary-builds

There looks to be a RTTY_IDLE_TIME setting for TBTracker that would potentially allow the crystal drift to settle before transmitting.

73

Mark VK5QI

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[Ben Z en de rest]

Can you share a bit of video with sound ?

Filter bandwidth comes to mind, sql, rev, much settings in dl-fldigi.

Grtz,

Ben

Op wo 24 mrt. 2021 21:51 schreef Mark Jessop <lennieth...@gmail.com>:

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