JXN Novik: the Norwegian Navy's VLF transmitter on 16.4 kHz

What you hear

Scroll the waterfall down past the submarine transmitters of Germany, Britain, France and Italy, past the point where most receivers stop showing anything useful, and at 16.4 kHz there is one more: a narrow band of data, a few hundred hertz wide, with the grainy, steady sound of minimum-shift keying when the receiver is in CW mode. This is JXN, the Norwegian Navy's VLF station at Novik, and in frequency it sits lower than any other station in this guide except the Russian Alpha navigation system. The wavelength is over eighteen kilometres. There is nothing to decode; the stream is encrypted and the only thing a listener can take from it is the fact of hearing it.

Whether it is on the air at a given hour is something only the receiver can tell you. VLF transmitters pause for maintenance, and a signal this far down the band is easy to lose in noise, so an empty waterfall at 16.4 kHz does not always mean the station is off.

Who transmits and why

JXN belongs to the Norwegian Navy and stands at Novik in Helgeland, on the coast of northern Norway. Its purpose is the one shared by every VLF station of its kind: to reach submarines that stay submerged, where ordinary radio cannot follow. Very long waves penetrate a few metres into sea water, enough for a boat at shallow depth or trailing a wire antenna to receive without surfacing, and a navy that wants its boats reachable keeps such a transmitter running. Norway operates submarines along a very long and closely watched coastline, which is reason enough for a transmitter of its own.

The content of the traffic is secret and encrypted, and that is where the knowledge ends. Details of the site and the antenna are not well documented in sources this guide would trust, and the article leaves them alone. The station's existence and frequency are public; listening to it is only receiving.

When and where to listen

The signal is strongest in Scandinavia, naturally: receivers in Norway, Sweden, Denmark and Finland hear it well at any hour. From Britain, the Netherlands, Germany and Poland it is readable on a quiet rural receiver, and from southern Europe it is faint. VLF propagation is stable by day and a little stronger, with more variation, at night, with a dip around sunrise and sunset along the path.

The practical difficulty is the frequency itself. Many public receivers have antennas and front ends that give up below about 20 kHz, and the lower the frequency, the more mains harmonics and switching noise crowd the picture. Choose a receiver in the countryside, preferably in Scandinavia, and give the waterfall a minute to settle before judging. The program tunes the station in CW with a passband of about a kilohertz, placing the data stream as a tone in the middle of the audio.

In ShackDeck

Station catalogue → Mystery stations → JXN Novik (16.4 kHz). The program picks a public receiver whose range reaches 16.4 kHz, tunes it and sets CW; no receiver, antenna or account of your own is needed. If the first receiver shows only noise, try one in Norway or Sweden: the station is hard to hear from afar, and that is part of the point of listening for it.