Chuck aa0hw's Blog (227)

QRQ CW "audio over ip" Morse Code Net server using ZeroTier SDN, Gstreamer & a Raspberry PI - LIVE demo with 4 OPs

Brief demo of 4 QRQ CW OPs in conference, full duplex, 2-way, OPUS CODEC, Gstreamer pipelines, using ZEROtier's SDN network ip tables...each OP connecting to the same RASPBERRY PI SERVER and receiving everyone's CW AUDIO a Raspberry PI 4 is setup as a selective forwarding unit(SFU)... so each incoming morse code audio stream goes right back…


Added by Chuck aa0hw on August 1, 2020 at 8:48am — No Comments

QRQ CW over Google DUO - LIVE demo - 60 wpm QRQcw Keyboard + paddles & Straight Key

testing GOOGLE DUO's ability to send CW over the internet, and finding the best settings to keep GOOGLE DUO from degrading the CW AUDIO TONES from its internal noise filtering, AGC and echo cancellation engines... (to stop Google Duo from doing that, a very tiny volume of low freq sine wave was applied(7.83 hz) and then the CW was also sent…


Added by Chuck aa0hw on July 5, 2020 at 7:51am — No Comments

QRQcw send/receive over ip test using the Jitsi Meet WebRTC App

end a text file from CWop1 over to CWop2, both using Jitsi Meet App for connecting online for a Morse Code audio QSO...turning off WEBCAM to save CPU usage and also using a specialized Jitsi Meet script that preserves the ORIGINAL CW AUDIO :…


Added by Chuck aa0hw on June 26, 2020 at 9:37am — No Comments

Raspberry PI 4 as a remote RIG over ip AFCW mode CW RIG keying interface - network stability test

sending a TEXT FILE at 60 wpm, from the REMOTE OP's PC, to a RASPBERRY PI 4 that is using the RIG's internal USB SOUND CARD as its own sound card....this test uses an RTSP SERVER:CLIENT audio over ip setup... the CW AUDIO you hear during this test is from the PI 4's TRANSMIT AUDIO MONITOR feed - going back to the REMOTE OP to get the PTT to…


Added by Chuck aa0hw on June 3, 2020 at 8:33am — No Comments

Raspberry Pi 4 - remote QRQ CW Keyboard using the AD5DZ recri keyer APPs + ZitaNJbridge

zitaNJbridge provides the near zero latency audio over ip link between the RIG/pi4 interface and the remote OP's desktop

recri keyer's CW Keyer APPs used from :…


Added by Chuck aa0hw on May 31, 2020 at 2:04pm — No Comments

Using the LOXJIE A10 60 Watt Class-D Audio Amplifier as an 88Khz LF Band QRQ CW Transmitter AMP

this is a follow video to this one in this series: PC's native MOBO sound card was set to 192Khz to enable direct 88Khz CW TRANSMIT from the AD5DZ CW KEYBOARD sending a text file

the LF RF 88Khz output of the PC's sound card goes to the input of the LOXJIE A10…


Added by Chuck aa0hw on May 22, 2020 at 1:43pm — No Comments

QRQ CW test - send CW at 96 Khz on the LF band at 96 wpm and send it to another OP over IP

brief experiment to see if by using the maximum sample rate of a sound card, 192Khz, would allow sending QRQ CW at 96 Khz(the highest frequency possible at 192Khz sample rate) at 96 wpm

Gstreamer scripts are used by the TRANSMITTER and RECEIVER

- TCP CW LF RF over IP -



gst-launch-1.0 -v…


Added by Chuck aa0hw on May 17, 2020 at 6:58am — No Comments

QRQ CW OPs - minimize CW ELEMENT spectrum splatter when transmitting QRQ CW on your RIG - with this:

1. send AFCW MODE

2. use this GSTREAMER BANDPASS FILTER between your CW KEYER's audio output and the RIG's LINE INPUT


gst-launch-1.0 jackaudiosrc ! queue ! audioconvert ! audiowsincband mode=band-pass lower-frequency=600 upper-frequency=800 length=700…


Added by Chuck aa0hw on May 16, 2020 at 7:43am — No Comments

experimental QRQ CW TRANSMIT FILTER to achieve a very narrow RF bandwidth on QRQ CW TRANSMIT - VLF BAND TEST

VLF BAND TEST on 10101 Hz

20 watt VLF AMP to compact DELTA LOOP ANTENNA

received by a Ferrite rod RX VLF antenna connected directly to this recording laptop's MIC INPUT jack, demodulated from VLF into CW AUDIO by the AD5DZ SDR APPs: LO-MIXER & FILTER modules



Added by Chuck aa0hw on May 9, 2020 at 4:40pm — No Comments

The AD5DZ MODULAR SDR software - demo of the AD5DZ SDR modules used to receive a VLF band QRQ CW signal

using all AD5DZ SDR software MODULES to capture & demodulate a QRQ CW signal heard on the VLF BAND at 10101 Hz...this video also shows one special adjustment made to a RECRI KEYER FILTER file setting to create a custom CW AUDIO BANDPASS FILTER for QRQ CW RX copy

a VLF RX ANTENNA - tuned bi-coil ferrite rod - brings in the VLF SIGNAL…


Added by Chuck aa0hw on May 3, 2020 at 2:30pm — No Comments

QRQ CW @ 120 wpm on the VLF BAND - RX on QUISK SDR + 2 Gstreamer Bandpass Filters to help

brief demo of picking up a QRQ CW signal on the VLF BAND @ 12 Khz, using this VLF RX - bi-coil Ferrite Mass Antenna(FMA) -

in this demo, 2 specialized Gstreamer bandpass scripts are used:

1. one to match the VLF BANDWIDTH of QUISK SDR

2. another one to filter…


Added by Chuck aa0hw on April 26, 2020 at 8:53am — No Comments

CW Copy Practice using a CW MIDI file & a variable speed MIDI player with The AD5DZ CW Keyer

brief demo using REAPER as a variable sped CW MIDI FILE PLAYER ...sending a text file that has been converted to a CW MIDI file by a CW TEXT to MIDI converter like Morse Midi or ehoCW

the VARIABLE SPEED on REAPER is excellent and the timing is very accurate at any speed you dial in

the AD5DZ CW KEYER has many CW parameter adjustments,…


Added by Chuck aa0hw on April 22, 2020 at 7:52am — No Comments

QSO QRQ CW using 17 Khz CW VLF RF over ip by a Gstreamer OPUS CODEC script to a Remote VLF TX antenna

Experimental Morse Code QRQ CW setup over ip to send VLF RF CW at 17Khz using the OPUS AUDIO CODEC - to a remote TRANSMIT ANTENNA located at the other OP's QTH... the other OP receives the VLF TX RF using a small FERRITE BOBBIN CORE INDUCTOR COIL antenna hooked directly to their PC Mic or Line, soundcard input

the 17Khz CW TX/RX by the…


Added by Chuck aa0hw on April 21, 2020 at 10:00am — No Comments

QUISK SDR APP for CW QSO on MUMBLE iCW Server - CW at 10 Khz VLF RF over IP - several advantages

the QUISK SDR APP provides several useful functions for conducting CW QSO's over ip at VLF RF(10Khz) on the iCW MUMBLE SERVER:

1. QUISK has Tx/Rx RIT - you can…


Added by Chuck aa0hw on April 16, 2020 at 10:58am — No Comments

QRQ CW on The Dreamer's Band - VLF(sub 9 Khz) - LIVE demo

brief demo to test 7.373 Khz QRQ CW Transmit/Receive

on the VLF "Dreamer's" BAND:



Added by Chuck aa0hw on April 9, 2020 at 2:27pm — No Comments

QRQ CW Copy by Ear Practice - 11 CW Signals - speeds from 61 - 81 wpm - use an SDR APP to choose & listen

There are 11 CW signals to choose from,

each one at a different speed from 61 wpm to 81 wpm.

Use your own SDR APP on your own PC to scan each signal and choose the speed you would like to use for COPY BY EAR practice.

Use a Virtual audio cable as the YouTube browser playback device and set your SDR input to use the same…


Added by Chuck aa0hw on April 6, 2020 at 11:02am — No Comments

VLF-LF QRQ CW RF over ip - using an experimental REMOTE VLF-LF BAND Transmitter-Receiver server setup

brief demo of a REMOTE VLF-LF band transmitter/receiver with 9 QRQ CW ops present and sending CW

More details about the REMOTE VLF TRANSMITTER - REMOTE VLF ANTENNA here on playlist:…


Added by Chuck aa0hw on March 18, 2020 at 2:43pm — No Comments

20 Watt VLF QRQ CW transmitter(18.200 Khz) - AD5DZ CW Keyer, Audio Amp, 4 to 1 Balun, Delta Loop

Brief experimental setup using the AD5DZ CW KEYER, to directly send 18.200 Khz CW AUDIO to a 20 watt audio amp...from the audio amp output to a large BLUE IRON POWDER TOROID 4 to 1 balun - then to the input of a compact 21 foot long DELTA LOOP wire antenna with one leg of the delta loop connected to a series resonant capacitor(6uF)

This 4…


Added by Chuck aa0hw on February 20, 2020 at 4:44pm — No Comments

Narrow Band QRQ CW filter, 50 hz wide, 2 APP combo to get rid of ringing & howling - 50 wpm test

this is an experimental test setup to get rid of narrow band CW filter SEA SHELL BACKGROUND HOWLING, and QRQ CW Ringing...

by using a:



the gate silences the "in between" cw element sea shell howling, and ringing, but also causes key clicks...

the following CW BANDPASS…


Added by Chuck aa0hw on February 18, 2020 at 12:16pm — No Comments

VLF Transmitter(delta loop) - VLF Receiver(Ferrite Core Bipolar Tesla Coil) - QRQ CW demo

brief demo of testing a VLF TRANSMITTER and VLF RECEIVER for QRQ CW operations

this is a follow up video to the first two using a VLF RECEIVE - BIPOLAR TESLA COIL with a FERRITE CORE antenna...the Transmitter is a tiny DELTA LOOP(7 foot per side) fed by a 5 watt audio amp…


Added by Chuck aa0hw on February 16, 2020 at 2:19pm — No Comments

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