31 January, 2010

Propagation via aurora reflection

Northern Lights in Tromsø, Norway 
Here is a recording of the Swedish station SM6CNN in contact with me on 29. October 2003, 22:42 UTC on 28.024 MHz. The direct distance is about 275 km.

Note the noise-like signal which is typical for signals that have been reflected off the aurora on the higher HF and on VHF frequencies. There was a strong geomagnetic disturbance that day with the K-index at Dombås, Norway reaching a value of 9 which explains the occurrence of aurora reflection.

30 January, 2010

Polar flutter

Arctic areas
Here is a recording of JW/DJ3KR on Spitzbergen from 24. August 2007, at about 21:45 UTC. This was only a few minutes after I had contact with him on 7.002 MHz.

Notice the fluttery character of his signal. On this day it wasn’t too bad and it wasn’t too hard to copy his signal, but on other occasions, signals that travel over the polar zone may be impossible to copy correctly. The K-index in Tromsø, which lies between Oslo (60 deg. N) and Spitzbergen (78 deg. N), at the time was 0.

[Image source: regjeringen.no]

28 January, 2010

Moonbounced echoes on 6792.5 and 7407.5 kHz

Recently, a facility with big enough antenna (300 by 365 m) and high enough power (3.6 MW) was used to set a new record for how low in frequency one can go and still get echoes from the moon.

This was also done during the HAARP moonbounce experiment which encouraged radio amateurs to listen on 19 and 20 January 2008. At my location in Oslo, I only heard the direct signal from Alaska, but many in the US heard good moon echoes.