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...


Views: 1125

Comment by Chuck aa0hw on May 18, 2020 at 11:25am

Here is another video example of QRQ CW over 100 wpm - this time using a PC SOUND CARD LF BAND transmitter and a high Q FERRITE CORE receive antenna:

brief test to see how well QUISK SDR could pick up a QRQq CW signal sent from a QRPp PC sound card CW transmitter on the LF band at 48 Khz the AD5DZ CW KEYER/KEYBOARD APP can send CW directly at 48Khz to the sound card's headphone jack,(NOTE: the PC sound card sample rate was set to 192Khz for this demo) which has an audio cable connecting its output to the input of a very inefficient DELTA LOOP antenna(21 foot long)... the delta loop is somewhat "tuned" for peak output by a CAP in series with the 2 ends of the loop wires...the DELTA LOOP is fed by a 4 to 1 balun that the headphone jack connects to first... the RX site has a high Q, passive, AIRDUX COIL/ferrite rods core, tuned to 48 Khz that significantly increases the RX signal strength, and is inductively coupled to a TWIN COIL FERRITE ROD RX ANTENNA that the PC sound card 48Khz LF BAND receiver connects with from the MIC INPUT jack, that the QUISK SDR is also using for its input...each coil of the TWIN COIL FERRITE ROD RX LF BAND ANTENNA, is also tuned for peak RX SIGNAL strength by adding just enough capacitance to the coil windings(parallel resonance)

Comment by Chuck aa0hw on October 19, 2020 at 10:04am

Here is another video example where you can SEE and HEAR the difference this filter makes in making QRQ CW OVER 100 wpm sound better, and TRANSMIT BETTER

brief demo - with visual and audio proof of a better spectrum output when sending and transmitting QRQ CW above 100 wpm(afcw mode) - where at these high speeds the RF BANDWIDTH OUTPUT of the RIG from keying CW at this speed will increase as well as the CW NOTE edge noise will become more and more pronounced... a system of using 2 CW BANDPASS FILTERs in tandem, to significantly eliminate EDGE NOISE and unwanted harmonics from being transmitted with increased RF bandwidth is therefore proposed using the AD5DZ "FILT MODULE" - as shown in the video https://github.com/recri/keyer

for more videos about CW OVER 100 WPM please see our playlist here:


NOTE: the type of math used in the RECRI KEYER dsp filter module does not distort the WAVESHAPE from its raised cosine RISE/FALL formations

NOTE: for AFCW mode, this filter TANDEM SETUP - provides the ideal amount of delay, (between 18 - 20 ms) which is ideal for AFCW keying the RIG setup on LSB...where a PTT tone of 5555 hz is sent FIRST....to activate the RIG's PTT VOICE VOX circuit ...BEFORE the filtered CW AUDIO TONE arrives...so that the PTT is fully ON just barely before the CW TONE arrives and gets transmitted by the RIGs LINE INPUT/SSB RF circuits...allowing the most QSK RX audio ...(search from "REMOTE RIG" in this YT channel for more info on these setups)

Comment by Chuck aa0hw on November 24, 2020 at 10:59am

Here is another video demo of using a method to limit the CW TRANSMIT BANDWIDTH when keying the RIG with CW OVER 100 WPM

brief demo showing the use of 2 CW BANDPASS FILTERS in series that prevent HF spectrum splatter when transmitting QRQq CW above 100 wpm...

this demo sets the wpm at 131 wpm for an extreme testing of this method to limit the CW TRANSMIT(AFCW mode) bandwidth the CW FILTERS are from the AD5DZ RECRI KEYER SDR "filt" modules https://github.com/recri/keyer

Comment by Chuck aa0hw on November 26, 2020 at 1:16pm

Here is another example of QRQ CW over 100 wpm - this time using VLF at 21 Khz & a Raspberry pi 4 dedicated VLF RECEIVER

this is a follow up video from the first video that shows more details of this setup using a PI 4 as a dedicated VLF RF over ip RECEIVER - https://youtu.be/RKvGe4siysc

in this video, CW is sent at 101 wpm to give the system a challenge...to see how well everything will work in the system together to produce high quality QRQ CW

Comment by Chuck aa0hw on December 2, 2020 at 10:26am

QRQ CW @ 101 wpm using 1 hertz CW audio output - transmit over ip using AC3 codec - RX/demod @845 hz

the ac3 codec with RTP PAYLOADING via GSTREAMER, was used to transmit 1 hz CW AUDIO output from a CW KEYBOARD sending at 101 wpm.... then received via Gstreamer and transformed perfectly into a well constructed CW note at 846 hz using the RECERI KEYER lo-mixer and filter SDR modules https://github.com/recri/keyer

This experimental setup was used to see how well the AC3 codec would perform at 1 hz and preserve the original 1hz audio waveform from the CW KEYER sending QRQ CW at 101 wpm https://gstreamer.freedesktop.org/documentation/libav/avenc_ac3.html

NOTE: the OPUS CODEC did not work well at all...the opus receive 1hz waveform was too erratic going above and below the zero cross over point... making demo'Ding the 1hz CW - sound horrible and unintelligible

Comment by Chuck aa0hw on January 22, 2021 at 12:53pm

Here is another VIDEO demo of TRANSMITTING CW on an ELECRAFT K3S at 120 wpm using the CW KEYing APPs from RECRI KEYER by AD5DZ

several tests are going on at the same time in this experiment 1. keying CW on an ELECRAFT K3S above its advertised top speed 2. using custom designed CW notes by Recri Keyer to produce raised cosine edges that are also bandpass filtered before going to the RIG's SSB LINE INPUT for transmit out on LSB via MCW... the CW BPF module prevents harmonic spillover and hF rF bandsplatter - by keeping the CW TRANSMIT SIGNAL BANDWIDTH within less than 500 hertz - down to -160 db - even though the speed of the CW is so high 3. use a high pitch cw note at 2.5Khz - which helps to get rid of all of the 60 cycle HUM, Noise QRM,QRN that will be picked up by the RX ULF ferrite loopstick antenna at the REMOTE OPs RX location (the K3S IF SHIFT is set to 2.5Khz) and all CW is sent and received at LSB 2.5Khz ABOVE the ZERO BEAT RF FREQ.... RECRI KEYER SDR apps easily convert it back to any CW PITCH you want to receive at... https://github.com/recri/keyer

HERE is the same setup using PADDLES and STRAIGHT key right from the REMOTE OP's position

this is a follow up video from the first demo'N QRQ CW keying(afcw) of an ELECRAFT K3S here: https://youtu.be/E-L_W4rkyhQ

in this video, REMOTE IAMBIC PADDLES and a STRAIGHT KEY are also used to remotely MCW KEY the K3S from the REMOTE OP's position and the sidetone is monitored at low latency via a ULF BAND 2.5Khz LSB TRANSMITTER/RECEIVER Both the ULF TRANSMITTER and ULF RECEIVER are built using RECRI KEYER's CW KEYER & SDR apps: https://github.com/recri/keyer

The ULF TX/RX setup uses 2.5Khz as the chosen frequency - to get it away from the 60 cycle hum and its harmonics HOUSE EMF etc.. and to increase the frequency of the mixing products - so that they fall outside the bandwidth of the bandpass and low pass filters being used on the RECEIVE SIDE the paddles & st key key CW at the RIG via MCW/afcw mode using a frequency of 2.5 Khz The RIG's IF SHIFT is set to 2500 hz and the RIG receives cw also at 2.5 Khz at the REMOTE OP's laptop, the SDR APPS from AD5DZ easily mix the 2.5 Khz incoming signal from the ULF TRANSMITTER, and converts it to a CW PITCH of 580 hz(can be any cw pitch you choose by adjusting the LO-MIXER GUI DIAL)

Comment by Chuck aa0hw on January 26, 2021 at 1:38pm

Here is another video example of REMOTE keying of an ELECRAFT K3S at 131 wpm and receiving the RIG AUDIO over a 2nd transmitter - a ULF BAND TRANSMITTER operating at 2.5Khz


demo of SENDING and RECEIVING a QRQ CW TRANSMITTER on the ULF BAND AT 2.5 Khz - A remote CW KEYBOARD is sending at 131 wpm from its remote location - keying an Elecraft K3S(over IP) via AFCW MODE - using a 5555hz low volume PTT ACTIVATATION tone that goes ahead of the 2.5 khz CW TONE ...the PTT TONE activates the RIG's PTT CIRCUIT to turn on and get into full transmit mode on LSB fully...before the CW TONE arrives...so that the CW TONE is not used by the RIG's PTT CIRCUIT as a PTT ACTIVATION signal(preserves the start of the CW ELEMENTs so that they do not get chopped off by the delay of the PTT circuit) NOTE: the 5555 hz tone is too high in pitch and too low in volume to actually get transmitted -

to receive the ULF SIGNAL on this laptop...an ULF BAND ferrite loopstick antenna connects directly to the laptop's mic input jack and sdr apps take it from there to convert the 2.5Khz ulf RF signal to 832 hz CW AUDIO

the RECEIVE is only from the ULF Transmitter signal...the K3S headphone jack goes to the 30 watt audio amp to a 4 to 1 balun to a 40 foot long wire loop antenna this operation is at low latency so you can type on a CW KEYBOARD or KEY the PADDLEs or STRAIGHT KEY from the REMOTE LAPTOP station and still hear the sidetone in low enough delay to be able to key paddles and a straight key with no timing issues

Comment by Chuck aa0hw on February 4, 2021 at 12:06pm

Here is another video example of  QRQ CW over 100 wpm -  this video tests a REMOTE PI CW TRANSMITTER at 200 wpm - to test and see how it would key CW at that high speed

this video CW keying test runs at 200 wpm - and is using the same hardware/software setup for TX/RX as the previous videos here:




Comment by Chuck aa0hw on April 8, 2021 at 2:16pm

Here is another video demo of QRQ CW over 100 WPM -  REMOTE KEYING AN ELECRAFT K3S at 131 wpm

few things going on... - testing sending CW at 2.5Khz on the ULF Band using AFCW mode

- using a REMOTE RIG OPERATIONs setup on the LAN

using an audio amp to send 2.5Khz CW over the ULF BAND to a small wire loop antenna in the shack room,

sending ULF RF to a laptop SOUNDCARD SDR RECEIVER in another location in the building,

RECEIVE the CW ULF RF using a FERRITE LOOPSTICK ANTENNA connected to a laptop's MIC INPUT jack...demoD'ed and converted to lower CW pitch by SDR apps SDR APPs from RECRI KEYER https://github.com/recri/keyer

Comment by Chuck aa0hw on July 12, 2021 at 10:58am

QRQ CW 101 wpm on the VLF Band at 23Khz - sound card SDR VLF Transmitter & Reciever - LIVE demo

sound card SDR TX/RX uses the RECRI KEYER SDR modules:


instead of using the LO-MIXER modules from Recri Keyer's SDR ... to convert the 23Khz VLF CW down to audio CW... ZAMGATE is used instead to convert the 23Khz CW into @838hz CW, ...a CW REGENERATION method is being used... ZAMGATE in sidechain mode, holds back a pure since wave at @838hz on its top input port....the ZAMGATE bottom input port is "keyed" by the incoming 23Khz CW; picked up by the laptop's soundcard's MIC INPUT jack ferrite loopstick antenna...the output of ZAMGATE goes through a cw audio bandpass filter and then straight to the headphones... ZAMGATE also has adjustments for dialing in your preferred RISE & FALL time and the ZAMGATE THRESHOLD settings determines when the pure 838hz sine wave is allowed to pass through the zamgate top port to its output port...how heavy or light you prefer your cw keying to sound...etc... https://www.zynthian.org/engines/_engine-list/engine-zam


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