NRK 153 kHz shutdown, December 2019

Pieter-Tjerk de Boer, PA3FWM

[waterfall display around 153.000 kHz] On December 1, 2019, the 100 kW 153 kHz transmitter at Ingøy in Norway was switched off. This transmitter was located in the one of the northernmost points of Norway, almost as north as the North Cape, and apparently mostly served ships out there at sea. Many detailed pictures of the antenna can be found at Bernd Waniewski's website, who engineered the antenna system.

In western Europe, and in particular at my WebSDR receiver site in Enschede, The Netherlands, this transmitter was usually not audible, due to the strong signal from a transmitter near Braşov, Romania, on the same channel. However, I could monitor the switch off by creating a very far zoomed in waterfall display, since the two carrier frequencies are different by a fraction of a Hz. The brighter line on 153.0002 kHz is the Romanian station, the slightly less strong signal at 153.9995 kHz is the Norwegian one, clearly switched off around 23:06:10 UTC. [map]

Here's a plot of the signal strength of both signals during the last hour or so:
[signal strength graph]
Note that the Norwegian signal seems to be more stable, have less fading, than the Romanian signal; but it's also about 20 dB weaker.

Occasionally, the Norwegian signal was audible in the background of the Romanian one, for example in this recording: the foreground voice is speaking Romanian, but one hears music in the background (which I checked to indeed be the Norway station).

However, often when one hears something in the background it was (and surely now is) not the Norwegian station, but another station (e.g., the Polish station on 225 kHz) due to the ionospheric cross modulation, also known as the Luxembourg effect.

Text and pictures on this page are copyright 2019, P.T. de Boer, .
Republication is only allowed with my explicit permission.