Topband: QSB

[Robert Brown]

Friends in Radi Land

The recent postings about long-period (2-3 minute) QSB were interesting in 
that there seemed to be no magnetic/auroral activity at the time.  This 
suggested an origin associated with atmospneric motions affecting the 
ionosphere.  Such motions of the atmosphere and ionosphere are coupled via 
the dominance of numbers of atmospheric constituents over ionospheric 
electrons and the high collision rate of electrons and neutrals in the 
atmospbere. 

The question then comes down to the atmospheric motions.  In that regard,
one possibility would be vertical oscillations of atmospheric gravity 
waves (AGW).  Around sunrise such motions could give rise to a shutter 
mechanism by vertical transport of ozone, the vertical oscillations 
of the atmosphere varying the horizontal tranmission or passage of 
solar UV to the D-region.  

My own investigations of 55 kHz LF signals published earlier in the Low 
Band Monitor have shown about a half-hour delay of sunrise absorption of
low-band signals due to the presence of atmospheric ozone,  It would seem
that vertical motions of the local ozone layer could give rise to the QSB 
that modulated the strength of DX signals.

Just a thought,

Bob, NM7M