Stefan, there also appear to be some more Alpha frequencies in use 
occasionally this afternoon on approximately 12.50 (F6) and 12.70kHz 
(Fx) (single transmitter seen here). These are in addition to the 
usual suspects on 11.904 (F1) and 12.649kHz (F2) which have two 
transmitters audible. 

Mike, G3XDV

> Hi all,
> 
> Someone was testing again, very strong signals from 12...14 kHz.
> Capture taken from my VLF loop in the garden (20 dB sensitivity
> missing).
> 
>   73, Stefan
>