Chuck aa0hw's Blog – July 2022 Archive (20)

the Gstreamer Script used in this video example:

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gst-launch-1.0 -v alsasrc device=hw:4 ! "audio/x-raw, format=(string)S16LE, layout=(string)interleaved, rate=(int)48000, channels=(int)2, channel-mask=(bitmask)0x0000000000000003" ! tee name=t !…

Near Zero Latency passthrough... using this Gstreamer Script to create a custom CW AUDIO bandpass filter: (CW PITCH of CPO = @700 hertz)

gst-launch-1.0 -v jackaudiosrc ! audiowsincband mode=band-pass lower-frequency=580 upper-frequency=820 length=384 window=3 low-latency=true ! jackaudiosink sync=false…

SDR RECEIVER built from RECRI KEYER's SDR MODULES: https://github.com/recri/keyer

several common CW Transmit/RX issues show up on iCW

1. keyclicks/square wave on OP's signal

2. CW pitch/keying too soft on OP's…

testing using 2 ferrite bobbin core inductor coils inside thick pyrex glass measuring cups to provide high voltage isolation protection between a RIG/cw keyer and a PC soundcard's input

used for sending CW AUDIO over SonoBus by keying a TWIN-T oscillator

the output of the TWIN-T goes to a class D amp…

using the dummy sound card JACK set to 800Khz, a Raspberry PI 4 transmitter sends LongWave CW to a laptop receiver over ip using these Gstreamer scripts:

/Pi4 TRANSMITTER:\

qrq@pi4b:~ $

gst-launch-1.0 -v jackaudiosrc ! "audio/x-raw, channels=1" ! audioconvert ! rtpL24pay ! udpsink…

FLdigi is keying a TLC555's pin 4/POS rail to send out a square wave CW NOTE at 1850 hertz - goes to a PI4 usb sound card's LINE INPUT...goes to a HILBERT CELL, then a BANDPASS FILTER(centered at 1850hz) then to a GAIN MODULE(+3db) then to an LO-MIXER that allows you to choose ANY CW PITCH and still keep the bandpass audio filtering bandwidth…

- a Pi4 has a usb sound card with LINE INPUT/line output/headphone output

- fldigi is keying a 555 square wave oscillator(by connecting pin 4 of the 555 to its POS RAIL through an H11F1 OPTOisolator chip) using FLdigi's KEY BY SERIAL PORT RTS PIN feature and sends its audio output to the pi's usb sound card's line…

Mixxx is a VARIABLE SPEED audio player that works great to slow down or speed up a QRQ CW audio file. Mixxx also has a REVIEW/rewind function that allows you to repeat the last word sent as many times as you want(by hitting the keyboard letter 'A' ...you can also repeat while slowing it down... MIXXX will change the cw frequency however....…

this video demo's a RASPBERRY PI 4, SETUP as a high performance morse code practice oscillator using RECRI KEYER CW modules

https://github.com/recri/keyer

TEENSY-LC usb midi board with recri midi-keys embed firmware…

RECRI KEYER sdr modules from AD5DZ:

https://github.com/recri/keyer

SETUP:

a square wave from a TCL555 655 hertz oscillator is being keyed by FLdidi's serial port RTS PIN feature.... the 655hz SQUARE WAVE goes to the input of the sound…

testing out CARLA's plugin host, using an alsa USB sound card directly, on a Raspberry PI 4...also testing CARLA's experimental feature, 'ADD JACK APPLICATION' to include MUMBLE and a RECRI KEYER CW AUDIO BANDPASS FILTER into the CARLA CONNECTION BAY

FLdigi is keying a 555 square wave oscillator and sending into the PI's…

DEMO OF FLdigi QRQ CW sending at 80 wpm, using its SERIAL PORT RTS pin keying feature, keys an H11F1 fet opto isolator which keys a 555's (pin 4/pos) which sends its output square wave at @2600 hertz to the MIC INPUT of a laptop...which sends that 2600 555 square wave to the input of an AUDIO to MIDI app called TRIGGER MIDI MONO(TMM) TRIGGER…

KXstudio's CARLA

https://kx.studio/Applications:Carla

CARLA allows you to add a Gstreamer script in its JACK APPLICATION feature...then once the script is loaded, you can export the Gstreamer script as an LV2 plugin on Carla's RACK where it shows…

- testing a PI4 RTSP RTP L16 encoded server from GSTREAMER

- testing a homebrew'D TWIN-T CPO for its QRQ CW keying ability

- testing a custom build W3NQN GAUSSIAN bandpass filter to clean up the TWIN-T CPO's edge noise and harmonics

NOTE:    QRQ CW has a better sound…

https://streammyaudio.com/live

ARCHIVED whole stream is located here: CRSnet.mp3 (Jul 12, 2022 11:44:49 UTC)

https://streammyaudio.com/archive

a CW…

for more info on this special custom build for filtering QRQ CW, from W3NQN, please see previous videos and their notes in their video descriptions:

https://youtu.be/lrJF2Av4k90

https://youtu.be/QJEK184CZPA

USES a RADIO SHACK 3 way speaker crossover(woofer/BASS) that has added un-polarized electrolytic CAPs - to 'tune' it to peak signal at 700 hertz

REALISTIC 3-WAY UNIVERSAL CROSSOVER 40-1299…

SETUP: a TWIN-T oscillator is being keyed by FLdigi's RTS SERIAL PORT feature...

the TWIN-T has noise and harmonics

use SONOBUS's native input FX DSP apps, NOISE GATE & PARAMETRIC EQ to STOP THE NOISE and CLEAN UP THE twin-t's SIDETONE before transmitting it to the other OPs listening on your…

RECRI KEYER SDR MODULES from: https://github.com/recri/keyer

when using FLdigi's SERIAL PORT KEYING mode....the CW audio output form FLdigi changes from whatever it was set to, to a hard wired 1500 hertz... to change it back to any pitch you want, an SDR MIXER…

https://kx.studio/News/?action=view&url=cardinal-2206-released

https://github.com/DISTRHO/Cardinal…