All Blog Posts (374)

USES GSTREAMER script for both the SENDER and RECEIVER SEND 4Khz, 12Khz OR 20Khz to RX OP

here is the example using 4Khz

gst-launch-1.0 -v audiotestsrc freq=4000 ! audioconvert ! opusenc ! rtpopuspay ! udpsink host=(ip address of the RX OP) port=9999

RECEIVE OP script: gst-launch-1.0…

test to see how well a Pi4 MUMBLE iCW setup can handle all the apps it takes to setup up a MUMBLE INPUT and OUTPUT cw audio morse code RE-GENERATOR SYSTEM

80wpm QRQ CW test

https://sites.google.com/site/icwoip/

CARLA PLUGIN…

GLAME BANDPASS FILTER   http://plugin.org.uk/ladspa-swh/docs/ladspa-swh.html

iCW/mumble   https://sites.google.com/site/icwoip/

Carla Plugin HOST …

Brief Demo for sending QRQ CW over SONOBUS using KXstudio's Carla in "multiple clients" mode on a Raspberry Pi 4 SonoBus is also monitoring its input to be able to monitor the REGEN'd ZamGate CW sidetone in real time at near zero latency

a TLC555 is being keyed by FLdigi's serial port rts pin, TLC555 sending its audio…

https://github.com/gordonjcp/lysdr

i/q encoding of CW Signals from -3kHZ to -30kHZ & +3kHZ to +30kHZ was done with 12 CW KEYBOARD from RECRI KEYER…

http://www.4sqrp.com/hipermite.php

to reduce the unwanted harmonics & QRQ CW edge noise generated by a keyed TWIN-T's CW audio output...the HI-PER-MITE active audio cw filter is tested to see how well it cleans it up

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this setup uses the following hardware:

1. raspberry pi 4

2. TLC555 that is keyed by a CW KEYER's RIG KEYING jack...(the TLC555 is powered by the PI's own 3.3v power supply via its GPiO pins

3. usb sound card with LINE INPUT - this demo uses a Behringer UCA222 the keyed 555's audio…

test using bpsk31 over ip from one op to the other to coordinate frequencies for HF QSO NOTE: NO AUDIO is heard on this video demo....visual only FLdigi provies the ENCODING and DECODING of bpsk31 Gstreamer provides the OPUS codec encoding to convert bpsk31 from and to one OP to the other here are the scripts used in this example…

this video is a follow up to the first video here: https://youtu.be/RQh_4JW6adw

this video adds a CW KEYBOARD, and straight key to the Raspberry PI 4 iambic CW keyer shown in the first video... by using a 2nd keyed CPO at a different PITCH than the 1st keyed CPO in…

TLC555 timer chip square wave oscillator is being 'keyed' (pin 4/pos rail) by a CW KEYER & its iambic paddles AND also being keyed by FLdigi using FLdigi's serial port keying setup via a usb serial port adapter and keying the serial port's RTS PIN Both the CW KEYER and FLDIGI are keying the diode side of an H11F1 FET OPTOisolator chip and…

snd-aloop

alsa-loopback cable

virtual audio cable

via a Gstreamer TEE SCRIPT to take a keyed oscillator at the mumble sound card input... filter it 1st... and then send it to two places...

1. the mumble USB sound card's output so you can monitor your own…

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…