VLF/LF (Very Low Frequency/Low Frequency)

VLF: 3 KHZ - 30 KHZ

LF: 30 KHZ - 300 KHZ


The 2200m band (135.7 - 137.8 KHZ) is part of the LF (LowFrequency/Langwelle).


Antenna is a MiniWhip.

VLF-Converter (DD3ZE) converting 10 - 600 KHZ up to 10 MHZ.

Receiver is my SDR.

Just testing also a Low-Pass-Filter (<600 KHZ).

Recorded these unknown signals with Argo QRSS Viewer on 135.7KHZ

Recorded DCF77 on 76,2 KHZ USB with HDSDR/Argo

Recorded LORAN-C (Long Range Navigation) around 100 KHZ with HDSDR

Recorded ESR-Teleswitches

129.1 KHZ: Mainflingen (Germany)

135.6 KHZ: Lakihegy (Hungary)

139.0 KHZ: Burg (Germany)

Recorded WSPR (136.0 KHZ)

No signals:

Recorded WSJT-X (136.13)

No signals!

Recorded Opera (136.0 KHZ)

Recorded Argo QRSS (137.7)

No signals!