All Blog Posts (419)

zitaNJbridge provides the near zero latency audio over ip link between the RIG/pi4 interface and the remote OP's desktop https://kokkinizita.linuxaudio.org/linuxaudio/

recri keyer's CW Keyer APPs used from :…

this is a follow video to this one in this series:

https://youtu.be/YCJpS0kCbQ0the 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…

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 -

TRANSMITTER:

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gst-launch-1.0 -v…

1. send AFCW MODE

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

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

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

CW TRANSMIT VLF RF Gstreamer BANDPASS FILTER script…

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…

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) - https://youtu.be/ZKVurZ2KzDA

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…

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,…

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…

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

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

https://james.ahlstrom.name/quisk/

1. QUISK has Tx/Rx RIT - you can…

brief demo to test 7.373 Khz QRQ CW Transmit/Receive

on the VLF "Dreamer's" BAND:

https://sites.google.com/site/sub9khz/

http://www.southgatearc.org/news/2016/january/sub_9_khz_news.htm

TEST…

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…

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:…

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 to…

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:



1. SIMPLE GATE

2. SIMPLE CW BANDPASS FILTER

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

the following CW BANDPASS…

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…

this is a follow up video to the first one:

https://youtu.be/ON-tZWiCCPQ...

everything is the same in this video, except, this time we send QRQ CW at 80 wpm to test how it will sound over VLF and using SAQrx by itself - using its 300 hz wide bandpass filter - centered at 700 hz

and with…

brief demo showing QUISK SDR and a wire antenna hooked up to the PC's sound card input
- picking up a weak QRQ CW signal on VLF - 18 khz

- by using the AGC on QUISK SDR and sending the QUISK SDR receive audio through the CALF EQ 5 BAND lv2 plugin, the weak signal is brought up significantly to improve copy

REMOTE RIG QRQ CW KEYING - over ip - using Gstreamer scripts on a Raspberry PI 2b::RIG hardware interface, and a remote OP's Linux laptop, on the local area network, wired Ethernet, going through a Router and network switches

NETWORK CONDITIONS = poor

ROUTER = 20 yr old router, 100 mb limit...

ETHERNET CABLES = two "CAT 4" - 100…

brief demo of QRQ CW testing a Gstreamer CLI 1 liner - to get two different audio bandpass filters at the same time, staggered, and incremental, for their respective tones of 707 hz and 5555 hz

GSTREAMER CODE used in this BANDPASS FILTER TEST

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gst-launch-1.0 -v interleave…