February 2020 Blog Posts (9)

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…

Several Gstreamer scripts are used to perform REMOTE QRQ CW KEYING of a RIG(afcw mode) from the REMOTE OP's location using TCP audio over ip network packets through a router and network switches in the pathway(WIRED ETHERNET)

there are 2 Gstreamer BANDPASS filters applied before audio goes to rig for transmit:

1. 680 hz BPF Gstreamer…

https://github.com/lucianodato/noise-repellent

An lv2 plugin for broadband noise reduction

brief demo showing how noisy the ELECRAFT K3S transmit audio input monitor circuit is....and how well the Noise-Repellent LV2 Plugin takes out virtually all of that K3S background noise,…