[Lowfer] Re: Hifer reception this week

[Johan Bodin]

Jim, Lowfers,

Jim Moritz wrote:
> The waterfall traces are often blurred, and at one point last=20
> night, the signal from GA split into 2 distinct traces running =
parallel a=20
> couple of Hz apart.

That is interesting. I guess it must be a combination of multipath and
doppler shift. The trace separation tells the rate of change of the
difference between the distances of the two paths

One Hz of doppler shift on a 13.555 MHz signal corresponds to a
speed of about 22 m/s.  Those "heavenly mirrors" seem to be moving
fast...

I have been looking at the carriers from various HF broadcast stations
and they are more or less blurred. Quite interesting, the "line width" =
varies
from one day to another. One station may be less than 1 Hz wide one day
and as much as 20 Hz wide at the same time the other day. The reflecting
properties of the ionosphere seem to vary from calm to extremely shaky.


> SM6LKM's 14.1011MHz beacon has been harder to copy here - it is =
usually=20
> visible in the mornings, but generally much weaker than the =
trans-atlantic=20
> signals. Perhaps this is due to our antennas not being favourably =
aligned,=20
> or just that propagation at 14MHz works better over several 1000s of =
km=20
> than it does at 1000km

I think it has something to do with propagation.
My dipole wire runs N-S and should have its max lobes E-W. However, at a
height of 9m it is quite omnidirectional although the radiation pattern =
varies
somewhat with elevation angle.

73
Johan Bodin, SM6LKM