YO3BN - My Very First VLF Reception

Posted at - 6th March 2018

My Very First VLF Reception

I would like to share my story with you.

The last weekend was special for me, that's because I've made my very first VLF reception - on 2nd March 2018.
I knew about ELF-VLF bands and their properties since a long time ago, but I have never get in touch with them.
So, several days ago I just found myself playing with some JFET transistors designing VCR stages and wondered what if I would set up a common source amplifier on the breadboard and connect it to my MIC IN jack, should I receive something?
Installing an SDR software for my Linux platform, connecting the HF antenna to JFET gate and my headpohones and... I was in business :)

As you might imagine the hum noise was terrible with that wire, but through QRM somewhere on 18KHz I've found something appearing on the waterfall. Setting the frequency accordingly I was able to hear a very narrow rtty... IT WAS ASTONISHING!!!

It just started as a little experiment and I was able to pick up something at the very first attempt, so I double checked with the Twente WebSDR to convince myself. After some research, it proved to be the RDL transmitter on 18.1KHz, probably from Krasnodar/Russia. Very very COOL!! Then after, I've made countless improvements, mil-navy FSK broadcasts, atomic clock signals and statics around the globe become something as usual.

It is so much excitement in those bands, every time when I'm on my laptop I keep the receiver turned ON hoping to hear something. But I'm interested actually in receiving the natural phenomena which are deeply buried under the hum. Even so, I don't want to hear my HF radio again, it seems too obsolete by now HI HI!

At this moment my receiving hardware consists from a short wire outside, about 1m or so, a ground reference, several meters of coaxial cable, two tansistor stages, a JFET followed by a BJT, both in common source/emitter configuration nothing special, my old netbook and QUSIK + GNU/Linux. It's a poor receiver though.

So, for the future I'm plannig to build some kind of special receiver with multiple E-H antennas, phase shifters and mixers, be portable, etc. and go out there on a remote location to listen to our earth. It will be a long journey of experiments and observation. So, I cannot jump out of this train now, wish me luck!

73 de YO3BN