[Lowfer] vlf this morning in TN

[Douglas D. Williams]

Well, I woke up early this morning and decided to put on a pot of coffee
and, for a change, see what the VLF spectrum looked like.

This is 0-48 kHz with the antenna (Z1203) connected through a 50 kHz low
pass filter into the PC mic input.

http://i81.photobucket.com/albums/j231/Goranothos/vlf1.jpg

Good amount of MSK signals, with NAA by far the strongest.

I switched the display to show only 11-27 kHz and caught a Russian station
beginning a transmission on 20.5 kHz.

http://i81.photobucket.com/albums/j231/Goranothos/vlf2.jpg


It appears the lowest frequency manmade communications signal I am getting
is HWU in France on 18.3 kHz. I was hoping to receive some Alpha, but no
luck.


I enjoyed Andy Talbot's article on e-field probes in the latest Lowdown. I
am using a Clifton Labs e-probe and one of the features of the indoor power
coupler is it isolates the receiver input from "ground" via a floating
female BNC connector. The screen captures above were all taken with the
indoor power coupler left unconnected to station ground. The probe itself
is 50ft from my house attached to a grounded metal pole. Let me show you a
screen capture of what happens when I connect the ground lug of the power
coupler to my station ground.


http://i81.photobucket.com/albums/j231/Goranothos/z1203grounded.jpg


Nasty stuff. If I had a common mode choke in the feedline this might not
happen, but I am certainly getting far cleaner signals by only having the
antenna system connected to "ground" at the base of the e-probe and leaving
all the equipment in the shack "floating". As always, YMMV.


Doug KB4OER