开云体育

ctrl + shift + ? for shortcuts
© 2025 Groups.io
  1. QRPLabs
  2. Topics

QMX+ and DTR/RTS like CW keyering

 

Hello dear all and devs,

Several hams on our side have equipped themselves with the QMX+.
Some would like to know if it would be possible to add a few lines of code to the firmware so that when PTT is triggered—either via CAT or through DTR/RTS emulation—and the QMX+ is in CW mode, it would transmit a carrier.
From our tests, this already works in Digi mode, where a tone is sent through the sound card emulation.
However, in CW mode, when PTT is sent via CAT, the radio does switch to transmit, but no signal is actually emitted.
It might work if the software sent a tone via the sound card, but most CW software assumes that PTT alone is sufficient.
This request is therefore aligned with improving compatibility with most CW-capable software (e.g., fldigi in CW mode with PTT via CAT or RTS/DTR).
One of the advantages of operating in CW with the QMX+ is also the ability to reduce receive bandwidth, onboard decoding, breakin etc.
We believe only a small firmware adjustment would be needed to have the carrier generated automatically, since the radio already enters transmit mode via CAT PTT.
Adding RTS/DTR handling would enable a simple and widespread configuration method for this kind of operation.
Otherwise, some have considered building interfaces using FT232 chips and optocouplers, but it would be unfortunate to require extra hardware when just a few lines of code might suffice.
Perhaps the addition of a CW submenu to automatically enable the carrier when PTT is activated?

Thank you in advance.
 

Currently, when operating CW with fldigi and QMX+, if you set the fldigi CW modem set for CAT keying, fldigi uses the CAT 'KY' command to send the characters - it does not try to use PTT to turn the carrier off and on for dit and dah.? This seems to work fine with QMX, but there is a bit of a trick to it: you need to set the fldigi CAT keying to use 'Elecraft', not 'Kenwood'.? [Note that you leave flrig radio set for QMX, only the CAT keying to Elecraft.] ? For some reason the 'Kenwood' setting fills each KY command with one character followed by many spaces; this fills the QMX buffer with spaces and does not work correctly.? But the Elecraft setting sends one character per KY command, and works for me.?? It would be nicer if fldigi sent several characters per KY command, and just let QMX keyer do the timing.
?
I have not done extensive testing with this, but it seems preferable to having QMX assert carrier with each TX, and is already in the firmware.
?
Stan KC7XE
 

Many thanks Stan for this infos. I will now tests with my qmx+ and fldigi.
 

With the config CAT keying "Elecraft" its work fine. Many thanks Stan for your help.
Andre F6APU.

1 - 4 of 4