Chuck aa0hw's Blog (403)

Interrupt Modulated(IM) QRQ CW Mode - Live demo on the VLF band

Interrupt Modulated(IM) QRQ CW Mode transmitting and receiving digital information using an analog carrier where the required bandwidth is limited to approximately the frequency of the analog carrier signal. The method is called interrupt modulation and consists of interrupting an un-modulated carrier signal so the…


Added by Chuck aa0hw on March 28, 2024 at 9:49am — 1 Comment

rEvErSe iMaGe CW mode FiGHTS BACK against packet loss during an OPUS CW AUDIO over iP Morse Code QSO

USING rEvErSe iMaGe CW(riCW) MODE to minimize AUDIO GLITCHEs from poor internet performance with lots of packet dropouts...using an riCW encoder & riCW decoder the riCW encoder injects silence into an audio carrier to represent each CW ELEMENT, the riCW decoder is using CW REGENERATION to convert the silent CW…


Added by Chuck aa0hw on March 23, 2024 at 8:00am — No Comments

Remote laptop station keying QRQ CW on Rig over LAN using NETJACK 2: using a pi2b Remote RIG interface

ultra-LOW latency REMOTE RIG CW OPERATIONs from a remote laptop on the local area 'wired' network, through router & switches using the NETJACK 2, setup demo from this video:…


Added by Chuck aa0hw on March 21, 2024 at 8:52am — No Comments

555 harsh raspy square wave CPO output to PURE SINE WAVE shaped CW NOTE output CONVERTER: REAPER DAW

using native plugins in REAPER DAW, to create a CW Regeneration "RE-KEYER"...- takes a harsh/raspy square wave input from a 555 keyed CPO output, over to the MIC INPUT(green wave on scope) and converts it into a shaped sinewave CW note output, with raised cosine edges, using 3 reaper plugins: Tone Generator, ReaGate,…


Added by Chuck aa0hw on March 8, 2024 at 8:54am — 1 Comment

reVerse iMAGE CW digital Mode - reduce ur Transmit bandwidth by at least half

experimental setup to send CW by 'keying' SiLENT GAPS into a narrow band 1600 hertz audio sine wave carrier, for transmit via LINE INPUT of your RIG(LSB/USB)

TRANSMIT ENCODER - by REAGATE's ducking mode output of TX REAGATE goes into a narrow bandpass filter before going to the TRANSMIT line input…


Added by Chuck aa0hw on March 1, 2024 at 2:49pm — No Comments

CW iambic KEYER by soundcard, 2 audio transformers & FREE software

using a 21Khz sine wave oscillator signal source, and 2 individual AUDIO THRESHOLD to CW MIDI output GATEs, and the RECRI KEYER's midi input iambic CW Keyer Module, using just one laptop Stereo sound card to route audio stereo audio outputs and stereo audio inputs a way to use just one stereo audio sound card native to…


Added by Chuck aa0hw on March 1, 2024 at 11:08am — No Comments

usE a FERRiTE TOROiD stepUP Transformer with a 32Khz sinewave to interface your Straight Key T UR PC

uses REAGATE GATE app to trigger a midi note output from the straight key 32Khz signal input to a sound card line input, output of REAGATE app sends a CW MIDI NOTE to key the RECRI KEYER's CW KEYER module

NOTE: this recri…


Added by Chuck aa0hw on February 28, 2024 at 2:37pm — No Comments

use Reverse Image CW method for super low bit rate OPUS CODEC audio over ip on the mumble iCW server

virtually perfect CW NOTEs in spite of using the lowest possible OPUS AUDIO CODEC bitrate on Mumble "8Khz"

- uses the REVERSE IMAGE CW METHOD for injecting silence into an audio stream, representing each CW ELEMENT; breaking up the 150 hertz stream with silent cw element blocks by using a REAGATE…


Added by Chuck aa0hw on February 27, 2024 at 12:29pm — 3 Comments

Hi Q, tuned, resonant, FERRiTE ROD TRANSMiT VLF ANTENNA for TX'n QRQ CW by a 'key'D square wave

using high Q, tuned, resonant VLF ferrite TX & RX VLF antennas(4.078Khz) a QRQ CW square wave into the resonant, tuned, high Q, TX antenna produces minimal harmonics...and even less of those harmonics survive by the time the same type of RX ferrite rod high Q, tuned, resonant, antenna removes even more of the…


Added by Chuck aa0hw on February 27, 2024 at 9:10am — No Comments

QRQ CW TX/|\RX high Q resonant VLF FERRiTE ROD antennas - how to combat ringing & element elongation

working with 4Khz VLF ferrite rod TRANSMIT and RECEIVE antennas that are High Q & tuned to resonance(see previous 2 videos for the more info on the FERRITE ROD HIGH Q antennas being used for TX & RX on 4Khz VLF):…


Added by Chuck aa0hw on February 23, 2024 at 10:53am — 1 Comment

ReaGate VST plugin - audio to CW midi NOTE output to midi input keyed, RECRI KEYER's iAMbic CW Keyer


AUDIO TO Midi CW NOTE OUTPUT converter by REAPER/reagate VST plugin…


Added by Chuck aa0hw on December 28, 2023 at 1:34pm — No Comments

using "FriTure"(A Real Time Audio Analyzer) for Morse Code Audio SPECTRUM, SCOPE & WAVEform analysis ;     has versions for WINDOWS, MAC, and Linux

RECRI KEYER's CW KEYBOARD, FILT & MIXER modules used in this video demo:

Added by Chuck aa0hw on December 28, 2023 at 9:31am — No Comments

VOiCE, Morse Code AND miniModem VLF Text Messaging over a 1 channel AUDiO over iP Gstreamer PiPEline

CW Keyboard, soundcard SDR MODULEs MIXER & FiLT from RECRI KEYER:

Added by Chuck aa0hw on December 24, 2023 at 7:55am — No Comments

attention POTA SOTA OPs: save 90 percent battery drain on transmitter PA by using a Pulse Density Modulated CW(PDM-CW) Generator by chatGPT C CODE - Live DEMO @30wpm

save 90 percent of your final power amp's battery drain using PDM-CW

instead of sending the full cw element length to the final PA,

PDM-CW sends 1 ms pulses per every 10 ms of cw element instead...

the receiver software patches back in the missing breaks in…


Added by Chuck aa0hw on December 18, 2023 at 5:43pm — 2 Comments

Low Latency REMOTE RiG, FULL DUPLEX, QRQ CW operations: 2 WAY audio, via Raspberry Pi interface & open source software

QRQ CW example, by, AUDIO OVER iP via a GSTREAMER raspberry pi TCP AUDIO SERVER and a GSTREAMER laptop TCP AUDIO CLIENT, organized by two PYTHON scripts.

- you can download the TCP SERVER and CLIENT python scripts here:



Added by Chuck aa0hw on November 22, 2023 at 3:28pm — No Comments

DiY TWiN COiL FERRiTE ROD VLF band RX Antenna - QRQ CW RX test - built from C. CRANE's TWiN COiL google patent info

using the info at GOOGLE PATENTs, this "TUNED" twin coil ferrite rod loopstick VLF Receive Antenna was put together from some spare parts in the shack, for a test run at 32Khz for receiving a QRQ CW signal at 32Khz…


Added by Chuck aa0hw on October 19, 2023 at 8:21am — 2 Comments

Pulse Density Modulated CW(PDM-CW) by CW KEYBOARD sending binaural beats via 2 sine wave oscillators

in AFCW mode, a CW KEYBOARD keys 2 sine wave oscillators at 1500 hertz & 1520 hertz, the beat frequency creates the PULSE DENSITY MODULATED CW beat frequency that will become the PDM-CW TRANSMIT SIGNAL sending to the TRANSMIT INPUT on LSB at 1500 hertz(AFCW MODE)

on RECEIVE, trigger midi mono…


Added by Chuck aa0hw on October 5, 2023 at 7:08am — No Comments

Pi4 40Khz CW Transmitter output to HEADHONE JACK: to diode/transformer frequency doubler/amp/antenna

brief demo of using a simple DIODE/TRANSFORMER frequency doubler to get 40Khz CW out of a pi4 headphone jack, by sending to the diode doubler input, 20Khz from the pi's headphone jack

Pi4 HEADPHONE PHONE to diode/transformer/frequency doubler to class D amp input, CLASS D OUTPUT to a series resonant cap to a FERRITE ROD…


Added by Chuck aa0hw on July 21, 2023 at 12:43pm — 1 Comment

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