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<DIV><FONT face=Tahoma color=#ff6600 size=5>RECEPTION OF SUBMARINE COMMUNICATION
SYSTEMS</FONT> </DIV>
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<P><FONT face=Tahoma>The Russian ELF transmitter Zevs,consists of t<STRONG>wo
swept-frequency generators of sinusoidal voltage</STRONG> and<STRONG> two
parallel horizontal grounded <FONT size=4><U>antennas, each about 60 km
long</U></FONT></STRONG>. The <STRONG><FONT size=4><U>generators provide 200-300
A</U></FONT></STRONG> <STRONG>currents in the antennas</STRONG>, in the
frequency range from 20 Hz to 250 Hz.<BR><BR>But there is one correction to be
made; <STRONG><U>the two parallel 60 km long antennas is not the antenna at all,
but the feedline</U></STRONG>. <U><STRONG>The actual antenna is the <FONT
size=4>earth</FONT> itself</STRONG>.</U> By building the antenna at a location
with a poor effective conductivity of the ground, and by grounding the ends of
the feedline / antenna, the signal is forced deep down into the earth, making
the earth itself the effective radiating element.<BR><BR>The actual look of the
visible part, the feedline, of this giant antenna, is much like the old
telegraph wires hung up on telegraph poles. Down from the last pole at the end
of each antenna leg, there is a thick copper wire down to the ground and
installed deep in a borehole, making up for the earth connection. (<STRONG>See
the open Lab article “Reception of submarine communication systems” by IK1QFK
and OH2LX for an principal sketch of an ELF antenna system</STRONG>
).<BR><BR>Calculations performed on <STRONG>data collected back in 1990, also
show us that the 82 Hz Zevs ELF transmitter is 10 dB more powerful</STRONG> then
the <STRONG>US Navy 76 Hz ELF transmissions</STRONG> from the dual WMT/MTF
sites.</FONT></P>
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<P><FONT face=Tahoma>Fonte: ZEVS, THE RUSSIAN 82 Hz ELF TRANSMITTER A Extrem Low
Frequency transmission-system, using the real longwaves By Trond Jacobsen at
ALFLAB, Halden in Norway. </P></FONT></BODY></HTML>