"Reg Edwards" wrote in message
...
Frank wrote -
Some approximate examples at 7 MHz with angles of incidence
from 0 - 40 degrees:

Sea Water 0.2 dB
Rocky Ground 5 dB
Average Gnd. 2 dB
=========================================
Thanks Frank,

Your figures for 7 MHz are representative of HF.

Nobody is particularly interested in MF, LF or VLF.

They confirm my latest estimate of an average, between sea water and
dry land, of roughly 3.5 dB per ground reflection.
----
Reg.

No problem Reg. I did the computations recently trying to estimate the path
loss, on 7 MHz,
from the west coast to Europe via the long path. The various ground losses
from all kinds of ground, including polar ice, and fresh water, are all
fairly low. The real problem was to estimate the losses due to the
incidence with the diffuse, conductive, ionospheric plasmas, and also to
consider
the possibility that some inonospheric ducting occurs. So far I have not
attempted to estimate these losses, but they must be very high, since only
considering ground incidence produces unrealistically
low path losses.

Frank