Chuck aa0hw's Blog (288)

using FLdigi on pi4 to key CW on RIG via RTS serial port pins & send out CW AUDIO at the same time

when using FLdigi 's serial port KEYING seems to change whatever the CW PITCH was before, and move it up to 1500 hertz... to get it back to a desired PITCH 3 plugins are used to RE-CREATE the FLdigi CW audio note output...


ZAMGATE (in sidechain…


Added by Chuck aa0hw on June 30, 2022 at 12:18pm — No Comments

using a simple Calf BandPass Filter LV2 plugin to clean up square wave, raspy, harsh sidetone QRQ CW




FLdigi is keying the PI 4's usb serial port's RTS PINs the RTS pin is…


Added by Chuck aa0hw on June 30, 2022 at 11:10am — No Comments

Remote QRQ CW Keying(AFCW mode) & Receiving of a Rig(K3S) over IP using a Raspberry Pi2b & Sonobus

the PI2B, still has enough 'power' to function as a REMOTE RIG OPERATIONs interface FLrig(from the pi2b's installed apps) is used to control many functions of the K3S

using ssh -X the PI2b's FLrig GUI appears on the remote laptop's…


Added by Chuck aa0hw on June 27, 2022 at 8:21pm — No Comments

QRQ CW QSO over ip using "1" multi-function multipurpose Gstreamer script on a Raspberry PI 4

GSTREAMER SCRIPT used in this example on the PI 4:


pi@raspberrypi:~ $ gst-launch-1.0 -v alsasrc device=hw:3 ! "audio/x-raw, layout=(string)interleaved, rate=(int)48000, format=(string)S16LE, channels=(int)2,…


Added by Chuck aa0hw on June 24, 2022 at 12:14pm — No Comments

A multiple DSP PLUGin(s) Connection Bay for PulseAudio using "Carla" - QRQ CW over SonoBus example


SETUP: A FET H11F1 OPTOisolator is being 'keyed' by the serial RTS PIN from FLdigi's CW KEYBOARD... the output of a 555 square wave oscillator is running continuously and attached to the output pins of…


Added by Chuck aa0hw on June 24, 2022 at 7:00am — No Comments

QRQ CW harsh square wave notes from 555 CONVERTED to a pure sine wave notes with raised cosine edges

This Gstreamer Script has the internal BandPass Filter used by the PI to take the QRQ CW SQUARE WAVE notes(@84wpm) from a 555 timer chip CPO's audio output, that is being keyed by a CW KEYBOARD, with the 555 output going to the PI's usb mic jack input...this Gstreamer Script filters out all of the harmonics AND puts a raised cosine edge on…


Added by Chuck aa0hw on June 17, 2022 at 11:42am — 3 Comments

CW SIDETONE CLEANER - polish up and take the harshness out of that Sidetone with Zamgate & BP Filter

zamgate is a used as a 'GATE', to help balance and equalize the RISE/FALL time of the original CW NOTE passing through it

a BANDPASS FILTER, finishes the job by cleaning up and reducing the unwanted/unpleasant Morse Code audio…


Added by Chuck aa0hw on June 16, 2022 at 7:55am — 3 Comments

sending QRQ CW over SonoBus on an iPHONE using a lightning to headset adapter & CW Keyboard Keyer

brief demo of keying a TWIN-T sine wave oscillator and sending the CW AUDIO TONE output from the TWIN-T to the MIC INPUT of an iPHONE LIGHTNING to HEADSET (Mic & Headphone) adapter…


Added by Chuck aa0hw on June 13, 2022 at 12:26pm — No Comments

QRQ CW Keying of a TWIN -T sine wave oscillator - LIVE demo @60 wpm - show waveform & spectrum of CW

built this TWIN -T - long time ago with the idea to be able to adjust the RISE and Fall TIME individual(via steering diodes) using the 3 variable resistor POTs for pitch, symmetry & rise/fall time circuit also uses a 5V regulator to stabilize the pitch and a 10K output resistor before going to audio input of…


Added by Chuck aa0hw on June 10, 2022 at 1:30pm — 2 Comments

Build a "keyable" Morse Code Practice Oscillator using the free Cardinal Modular Synthesizer

Build your own 'MIDI' "keyable" Morse Code Practice Oscillator



Added by Chuck aa0hw on June 9, 2022 at 8:00am — 2 Comments

using a variable PULSE GENERATOR Gstreamer script - to help adjust in realtime, a CW Bandpass Filter

Gstreamer Script used in this demo:

gst-launch-1.0 -v audiotestsrc wave=ticks apply-tick-ramp=false tick-interval=100000000 freq=2000 volume=0.5 sine-periods-per-tick=40 ! audioconvert ! autoaudiosink

also being shown in this demo is CW REGENERATION, using ZAMGATE in sidechain…


Added by Chuck aa0hw on June 3, 2022 at 10:23am — No Comments

LSP PLUGINS to create a 'keyed' MORSE CODE PRACTICE sine wave OSCILLATOR with raised cosine edges




IN sidechain mode, the gate will not let the OSCILLATOR MONO SINE WAVE pass through its upper port

however, when keyed by another CW…


Added by Chuck aa0hw on June 3, 2022 at 7:49am — No Comments

Text Message Encoding @ 200 wpm taking up only 20 hertz of RF BANDWDITH using Extreme Narrow Band CW

RE: ENB-CW please see this playlist here for more info on this new CW MODE:…


Added by Chuck aa0hw on June 2, 2022 at 9:26am — No Comments

get rid of HIGH "Q" CW Narrow Band Filter Ringing with a GATE DSP plugin & filter: live demo @ 80wpm

GATE plugin used in this demo if from CALF STUDIO PLUGINS

Added by Chuck aa0hw on May 31, 2022 at 9:41am — No Comments

Key your RIG using FLdigi's new SERIAL PORT DTR/RTS CW RIG keying feature

The accuracy of having FLdigi key the RIG using its new serial port DTR/RTS keying circuit ...looks impression on first testing...

TESTING  at          120 wpm,  150 wpm and…


Added by Chuck aa0hw on May 28, 2022 at 12:46pm — 1 Comment

Raspberry PI 4 - CW Morse Code Audio Tone Regenerator - using PI-APP's Reaper DAW's own plugins

pi-apps has a REAPER download REAPER contains all of the plugins to REGENERATE CW

throw any kind of sidetone into the REAPER INPUT and REAPER OUTPUTs a pure SINE WAVE, raised cosine edged CW AUDIO TONE, that perfectly clones the exact length of…


Added by Chuck aa0hw on May 27, 2022 at 7:44am — No Comments

SonoBus i/q Stereo - VLF CW/IP - Morse Code server - on a Raspberry PI 4 - uses LYSDR to demodulate

TEST SETUP to use SonoBus in a LOOPBACK SERVER MODE (you have to mute all contacts but the PI 4 server)

TO SEND VLF RF CW directly, and send in i/q stereo you need a CW KEYER like Recri Keyer…


Added by Chuck aa0hw on May 26, 2022 at 8:59am — No Comments

copying QRQ CW in a TUNED RESONANT HIGH "Q" system - DEMO a GATE between 2 CW audio bandpass filters

QRQ CW TRANSMITTER & RECEIVER are both using HIGH Q resonant systems on their Ferrite Loopstick ANTENNAs

PROBLEM - HIGH Q will cause ringing and MUSH on the RECEIVE signal

SOLUTION - use a GATE between 2 CW AUDIO BANDPASS filters

Added by Chuck aa0hw on May 16, 2022 at 10:10am — No Comments

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