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DL4YHF@aol.com wrote:
<blockquote TYPE=CITE><font face="arial,helvetica"><font size=-1>Hello
Group,</font></font>
<p><font face="arial,helvetica"><font size=-1>Has anyone of this group
ever heard about signals in the range of 25 Hz, like this:</font></font>
<p><font face="arial,helvetica"><font size=-1>- a few pulses of about one
second length each, about 4 seconds pause between them</font></font>
<br><font face="arial,helvetica"><font size=-1>- transmitted irregularly,
sometimes not present for days or weeks</font></font>
<br><font face="arial,helvetica"><font size=-1>- obviously NOT related
to the mains line, no harmonics or images at 50 and 75 Hz etc</font></font>
<br><font face="arial,helvetica"><font size=-1>- seem NOT to travel through
the mains line.</font></font>
<p><font face="arial,helvetica"><font size=-1>The following is quoted from
Renato Romero:</font></font>
<p><font face="arial,helvetica"><font size=-1>>>>Hi Wolf,</font></font>
<br><font face="arial,helvetica"><font size=-1>about that strange signal
at 25 Hz: I receive that signal since 1997, when I started with regular
reception below 50Hz thanks a circuit of IK1ODO with OP07 op amplifier
and a big T marconi antenna. Those strange dots appear sometimes, not always
at the same time, and not always in the same form: sometimes there are
one o two dots, sometimes there are 13 dots or more. They disappear for
many days, then appear again with a not regular schedule.</font></font>
<br><font face="arial,helvetica"><font size=-1>About the origin: agree
with you about the not natural origin, is clear; but what they really are
... it's a mystery.</font></font>
<br><font face="arial,helvetica"><font size=-1>They are not inducted by
main power lines because they are not present in the reception with a big
horizontal loop (30m x 30m, 3 turns), instead of the signals on the electric
line at 1024Hz, present on air and very strong in horizontal polarization.</font></font>
<br><font face="arial,helvetica"><font size=-1>They are not caused by not
linear loads on the electric line: that signals appear like a mirror with
50Hz (and 150Hz, 250Hz...): in this case there is no signal at 75 Hz.</font></font>
<br><font face="arial,helvetica"><font size=-1><<<</font></font>
<p><font face="arial,helvetica"><font size=-1>Any ideas ? Another submarine
"wakeup" transmitter ?</font></font>
<p><font face="arial,helvetica"><font size=-1>73, Wolf</font></font>
<br>
<br>
<p><font face="arial,helvetica"><font size=-1>P.S. Looking forward to Dick's
Feldhell transmission. Will try to answer in that mode, but I few its not
really suited for my low-power signal - so possibly will reply in CW.</font></font>
<br>
<p><font face="arial,helvetica"><font size=-1>P.P.S. Walter DJ2LF will
hold his LF talk at the Ham Radio fair in Friedrichshaven on Friday June
28, after 16:00 local in hall 2, room "C", after an introduction by DL1VDL.
.... at least, this is written in the german CQ DL magazine. They warn
about "problems with the parking space" this year and ask visitors to use
the shuttle bus. Hope to meet you there !</font></font>
<br>
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