Earth-mode VLF communications

Today I received a nice email from a station in The Netherlands on the subject of earth-mode communications. Apparently he had been inspired by my work and was still hoping to achieve better results. Earth-mode requires simple gear and simple test gear, but results can be unpredictable. It is an area where true experimentation is still possible. From my limited tests when I was fit (before my stroke) I am convinced there is a lot more to learn.

"Hello Roger,

How are you doing? I hope you are doing fine.

Since this is my first mail adressed to you, please let me first introduce myself.

My name Is Jan ( PE1AXM ) and I am a radio amateur since 1977 and live in the south-west part of the Netherlands, my age is 59.

My radio interests are mainly: making home made equipment.

About 1 year ago I discovered one of your articles that triggered my interest in 9kHz earth mode communication. So I started building. For Tx I use 2 earth rods, 2 meters long and separated 20 meters.Resistance between these rods is 16 Ohms.

A home made amplifier is capable of delivering 1 Amp into these earth rods.

For reception I use a small loop antenne that resonates at 9 kHz, followed by a low noise pre-amp and a PC with Spectran Plus software.

To be honest, I thought that a range of 4 km's would be an easy job, but I soon found out that this was not true.

My best dx so far is just over 1 km, but I realise that still a lot can be improved on my system.

Roger, I thank you for your stimulating articles and I hope that you will make further recovery."