[GreenKeys] Curious what folks winter rtty projects are.

[Harold Hallikainen]

On Wed, November 26, 2025 3:59 pm, abowman89 via GreenKeys wrote:
> Just interested in hearing what the winter rtty related projects are
> folks got cooking.Im trying to get my ittywxv3 ambitions to work. And
> maby wire my c64 into the mix for fun.

My long term project is continued development of the DSP TU at
https://w6iwi.org/rtty/DspTU3/ . The most recent update was adding support
for WriteLog. Also added a low pass filter between the loop current
detector and the Baudot software uart and AFSK generator to get rid of
contact bounce.

I was recently doing work on a Dovetron TU and saw a very clever idea for
autostart. The motor is started if there are fewer than N characters
between successive space characters. With noise, there could be 31
characters between spaces, but with plain text, there is likely to be 6 or
less. I'm thinking of adding something like this to the DSP TU to prevent
falsing of the autostart. We could require a sequence of N words
(separated by spaces), where each word is less than M characters, with N
and M being user configurable.

The next big thing is probably an HTTP and, ideally, HTTPS client for WiFi
so the DSP TU can get and print audio from stuff like
https://w6iwi.org/rtty/audio/npr . So far, the WiFi connects to an access
point, gets an IP address using DHCP, and gets the time using NTP. More to
go!

I'm also thinking of adding a simple spectrum display along the bottom of
the display to aid in tuning. I'm thinking of just plotting pixels based
on the time between zero crossings.

Then probably some code cleanup. Some stuff got a bit convoluted,
especially the display menus.

As part of the code cleanup, I'm thinking of generalizing the software
uart code so multiple instances can be run. This would allow for speed
conversion between the AFSK modulator, demodulator, and the loop.

When tarriffs finally settle down (if they do!), I'm thinking of ordering
10 assembled DSP TU boards and making them available to GreenKeyers that
want one but don't want to do surface mount soldering.

In other stuff, I'm going to try four elevated radials on my vertical
antenna since the landscaping crew keeps ripping up the on-ground radials.

Harold
https://w6iwi.org


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