QRQ CW over 100 wpm - tips, techniques and specialized QRQcw GEAR

This video is demo’N a setup to create a custom QRQ CW sine wave, raised cosine edged, ‘keyable’ oscillator

There are already 2 excellent programs for LINUX for a software QRQ CW KEYBOARD… FLdigi and TWQRQ...however, neither one of them are ‘keyable’ - this first video in a new video series on “QRQ CW OVER 100 WPM” uses Fldigi as a tool to build a new software QRQ CW pure sine wave, raised cosine edged, ‘keyable’ oscillator...that you can adjust weight both by TIME and by PERCENTAGE…you can also choose the raised cosine ‘window’, adjust pitch, volume, Q, bandwidth etc… NOTE: at QRQ CW over 100 wpm, many of the cw element parameters become critical for good copy… for example, the edge noise, in spite of the cw element having an 8 ms rise and fall time, increases with cw speed and must be reduced...the edge noise can get so loud as to be 50 percent of what you hear… the VSTs filter it out very well...

NOTE: headphones might be needed in order to hear the subtle cw edge changes
NOTE: only one speaker output is used for the video, to prevent 2 speaker phase issues while listening....you can use a STEREO to MONO adapter if you need to hear this video on both speakers..

first a 1000 hertz tone from Fldigi’s RT QSK CONTROL RT CHANNEL audio output goes to the input of the VST HOST’s first VST PLUGIN, a bandpass filter...which is centered at 1000 hertz...the volume of its output is CRITICAL to get the weight by TIME to work in the following plugins… [ - 1.74 db in this setup ]

the bandpass filter connects to the first REAGATE VST Plugin, where again the threshold volume(-.2 db) is critical to get the weight by TIME to work on the next plugin...another REAGATE…

the 2nd REAGATE PLUGIN is used for adjusting the WEIGHT BY TIME on the CW NOTE...the threshold slider in the middle is set to clone Fldigi’s weight and if you raise the threshold slider higher...you get lighter keying...if you lower the threshold slider you get heavier keying…

the next VST PLUGIN is called “sineCW” and is the heart of the system...where the 1000 hertz tone is used to create a new “cloned” cw element..sineCW lets you adjust the CW PITCH, VOLUME, bandpass filter bandwidth and Q, and rise/fall time

the final vst plugin is called the ENGINEERs FILTER, where we remove any remaining edge noise and select the filter ‘window’ to your preference...each window sounds a bit different...and allows more or less edge noise to get through to the audio output…

a text file from TOM’s, W4BQF, article about copying CW OVER 70 wpm is used...and demoN some of plugins while sending...


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Comment by Chuck aa0hw on September 5, 2021 at 1:08pm

Here is another example of QSO'n  QRQ CW Over 100 using the latest STUDIO LINK STANDALONE APP



playlist here:


Comment by Chuck aa0hw on October 29, 2021 at 11:00am

another use case example for QRQ CW over 100 wpm -  CW DATA over IP demo

USES a CW KEYBOARD/KEYER APP from Recri Keyer: https://github.com/recri/keyer

that can send CW at "ZERO HERTZ" (0, 1) ON/OFF(keydown/keyup) data stream -

uses TRIGGER MIDI MONO https://lsp-plug.in/?page=manuals&section=trigger_midi_mono

to convert the CW DATA into MIDI NOTE ON/off messages

which "keys" a sine wave CW Oscillator & CW BANDPASS FILTER modules from Recri Keyer: https://github.com/recri/keyer

CW data OVER ip - Transmitter & Receiver - by Gstreamer (EAC3 codec) https://gstreamer.freedesktop.org/

Comment by Chuck aa0hw on October 30, 2021 at 9:54am

SEND cw data over ip instead of CW AUDIO over ip - use a soundcard SDR mixer module to convert back to CW AUDIO

this is a follow up to the previous video on this topic starting here: https://youtu.be/hyGMRDvNLsU

in this video the DECODING of the CW DATA into CW AUDIO NOTEs is done with a soundcard SDR program from RECRI KEYER https://github.com/recri/keyer ...using its LO-MIXER to mix/convert the CW DATA received over ip from 0's &1's to CW AUDIO NOTEs with a frequency that you choose on the Recri Keyer LO-MIXER module

2 post Recri Keyer CW audio bandpass filter modules are used to clean up/clean out... the CW ELEMENT audio edge noise coming from the rapid start/stop/make/break/keydown/keyup etc....

THE PINK CW NOTE on the SCOPE VIEW shows the final wave shape of the decoded/demodulated CW from the CW DATA Over IP transmitter source the Gstreamer audio codec = eac3 is used to provide the pathway over ip from the transmitter location to the receiver location

here is an example of the TRANSMITTER GSTREAMER SCRIPT used: gst-launch-1.0 -v jackaudiosrc ! audioconvert ! queue ! avenc_eac3 ! rtpgstpay ! udpsink host=(ip address of the cw receiver) port=7777

here is an example of the RECEIVER GSTREAMER SCRIPT used: gst-launch-1.0 -v udpsrc port=7777 ! "application/x-rtp, media=(string)application, clock-rate=(int)90000, encoding-name=(string)X-GST, caps=(string)\"YXVkaW8veC1lYWMzLCBjaGFubmVscz0oaW50KTEsIHJhdGU9KGludCk0ODAwMA\=\=\", capsversion=(string)0, payload=(int)96" ! rtpjitterbuffer ! rtpgstdepay ! avdec_eac3 ! audioconvert ! jackaudiosink


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