Chuck aa0hw's Blog (358)

brief testing and comparing MP3 to OPUS from a CASTER.FM free online Radio Station setup and the iCW MUMBLE Server/client setup

a Raspberry Pi 4 is doing the transmitting to both MUMBLE INPUT and the RADIO STATION INPUT

unixCW is providing the APP to send repeating text files at different speeds and at…

This method uses 3Khz VLF RF CW over ip that is encrypted & stealth modulated

using MicroModulation methods to encode stealth, LiVE text messaging data onto an a VLF 3kHZ AM CARRIER wave .. can't see anything, or hear anything - sounds and looks like a 'dead' carrier wave with nothing on it...

METHODS the…

demo of using an iphone as a QRQ CW SonoBus Receiver - to choose & listen to multiple CW TEXT files(up to 18 different text files) being sent by unixCW's CW program from a pi4 'audio over WiFi' Transmitter NOTE: SonoBus, in MULTI-CHANNEL input mode, can send 18 different, individual audio sources at the same time, and the iphone sonobus…

Python QRQ CW Radio Station Receiver - modified from this python script: https://github.com/irsbugs/GStreaming/blob/master/radio_gui.py

sending CW text files on continuous repeat using unixCW's CW program…

custom w3nqn QRQ CW filter

https://imgur.com/zauJdeV

https://imgur.com/fxZoPUz

Rohde's AM Detector Circuit…

TERMINAL COMMAND for sending a CW TEXT file with UNiXCW/cw program (continuous REPEAT)

while true; do (./cw -d hw:0,1,0 -f ur.txt -w 73 -k 48 -t 852 -v 100); sleep 1; done

for unixcw's CW audio output - this script uses the alsa loopback snd-aloop cable(hw:0,1,0) to receive it uses alsa_in -d hw:0,0,0…

https://github.com/gordonjcp/lysdr demo of using LYSDR to demod 3 VLF frequencies at the same time using multiple instances of LYSDR and combing their demod'D audio outputs…

QUiSK SDR with the help of unixCW, gSTREAMER & RECRI KEYER allows a unique way to practice your CW copy by EAR

SETUP: unixCW's CW program is sending the same text file at speeds below & just above, say...a current comfortable CW copy by ear speed... pick a text file and speed that is no longer than 10 to 15…

uses FLdigi, Gstreamer and VIRTUAL AUDIO CABLEs the virtual audio cables take the CW AUDIO OUTPUT from FLdigi and send it to the OP's soundcard(for CW sidetone monitoring @ low latency) AND sends it over iP to the other CW OP(can use any audio codec via Gstreamer)

one Gstreamer SCRIPT does it all - grabs FLdigi's…

demo of setting up a pi4 to act as an RTSP virtual ham radio ionosphere SERVER that many OPs can connect to for QSO'n or just listening... this setup uses an i/q input above and below ZERO POINT by about 80 Khz worth of RF SPECTRUM - to gather together and QSO uses the gSTREAMER wavpack codec, and a gstreamer…

demo showing unixcw/CW sending 8 different CW Text files at 60 wpm to a pi4 QUISK SDR, using sonobus on the pi4 to send QUISK SDR demodulated output to the iphone sonobus// iphone using REALvnc to choose which pi4 QUISK SDR VLF SIGNAL to demod and listen to

UNIXCW CW…

brief demo using the sound card SDR modules from RECRI KEYER to downconvert 5 VLF CW signals from 16Khz to 20Khz converted/mixed down to CW audio at 700 hertz

https://github.com/recri/keyer

brief demo showing the REMOTE Pi4 VLF TRANSMITTER setup and a laptop soundcard SDR receiver using its own FERRITE LOOPSTICK ANTENNA to pick up the VLF signal from the remote PI's transmitter's loop antenna located in the other room

soundcard SDR modules are from RECRI KEYER…

demo uses TRIGGER MIDI MONO as a DE-Qer

TRIGGER MIDI MONO analyzes the input volume peaks of the HIGH Q CW elements then sends out a MIDI NOTE on/off message to a software midi input CW KEYER app like RECRI KEYER - https://github.com/recri/keyer (or…

3CX

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instead of sending a solid keydown of dits & dahs... when you key down using this method, only the smallest possible pulse width of the minimalist pulses per CW ELEMENT train, at the CW RF frequency of interest, is sent... saving battery power since the PWM key down is a tiny percentage of battery current/power being used when compared…

THE zamgate PLUGIN, in sidechain mode, does the DE-Q'n

https://www.zamaudio.com/

ZAMGATE analyzes/measures the incoming high q wavefront of the QRQ CW and regenerates a NEW QRQ CW Note with adjustable weight and rise/fall times

The tuning of the biploar tesla coil for 16Khz is quite sharp but dramatically increases the transmitter signal antenna output - the RX ferrite antenna is also tuned by a parallel cap (TRANSMITTER is a Linux laptop, RECEIVER Is a pi4) both antennas are using SOUND CARD SDR software modules from RECRI KEYER... to be able to send and receive…

qrq cw from a CW KEYBOARD by RECRI KEYER on a RASPBERRY PI 4 to a Behringer UCA222 to a CLASS D AMP to the FERRITE RODs ANTENNA ARRAY

https://github.com/recri/keyer

the high Q of 2 dsp CW AUDIO BANDPASS filter in series helps greatly to extract the ENB-CW modulated 8Khz carrier VLF Transmitter's signal

high Q CW BANDPASS filters otherwise would cause terrible ringing for CW; however, in this case... it actually helps

for more info on ENB-CW please see the playlist…