Model L-600S
ELF/VLF H-Field Loop Receiving System
The L-600S Receiving System
is designed for listening to VLF/ELF sig-
nals, spurious radiation and phenomenon below 10 kHz. The system con-
sists of the L-600 VLF receiver and L-600 VLF H-Field loop antenna.
The receiving system is highly directional and sensitive enough for effective
utility line noise tracing applications and for ELF research with the serious
Natural Radio experimenter in mind. The L-600S is an effective H-Field
receiving system for use in EMI noisy areas, or within E-field quiet areas.
The directional loop can be used for nulling out noise sources. Frequency
response is 300 Hz to 30 kHz (broadband). The 24 inch square PVC loop
may be broken down into components for storage. The loop antenna and
receiver may be hand held or tripod mounted. Switchable high pass filter
for noise reduction. The extended 30 kHz upper range can be used for
solar flare studies. Tape recorder and earphone outputs included with the
receiver for connection to a recorder, sound card or spectrum analyzer.
The L-600 VLF Receiver
is a current mode amplifier and audio amplifier
with with broadband loop equalization. Design features a broadband,
low-cut 1.5 kHz highpass filter for reduction of 60 Hz (hum) harmonics.
The L-600 VLF Loop Antenna
is used in a current mode broad band
configuration with the L-600 receiver input circuit. The loop is constructed
of double enameled - UV protected #28 copper wire, and is secured to a
light weight 24 inch diameter pvc collapsible frame.
Operation - The L-600 VLF Loop Antenna
The L-600 loop is a unidirectional unbalanced antenna that can easily null
out 60 Hz power line noise in normal listening situations. If you are sur-
rounded by power lines it will be difficult to null most of the noise effective-
ly. A good location some distance (300 meters minimum) from power lines
is best for VLF/ELF signal and phenomenon monitoring.
Rotate the loop for the best nulling or peaking of signals that you desire to
monitor. As little as 10 degrees of rotation can null or peak a signal. Use
the L-600 antenna with the recommended L-600 VLF receiver for best
results.
For permanent outdoor mounting, we suggest that the loop bundle and
contacts be coated with an anti-fungus varnish. The loop can be hand held
for portable operation or can be mounted onto a standard camera type
tripod. When tripod mounting, it may be easier to first mount the handle
separate from the loop, then reattach the loop to the handle.
Specifications - L-600 VLF Receiver
Receiver Size
4.19”L x 2-74”W x 1-57”H
Frequency Response
300 Hz to 30 kHz
1.5 kHz (-3 dB) to 30 kHz (-3 dB), 60 Hz (-35dB)
highpass/low cut mode.
Audio Output
300 mW maximum, 4-32 ohms (earphones)
10k ohms (recorder)
DC Power
9 volt, 7 to 10 ma typical
Specifications - L-600 VLF Loop Antenna
Loop Size
24 inch square (PVC pipe)
Loop DC Resistance
50 ohms typical (unbalanced)
Loop Inductance
28 mH
Loop Sensitivity
.23 µv
√
Hz @ 5 kHz
WARRANTY
LF Engineering Co. Inc. warrants that at the time of shipment the L-600 VLF
Receiver manufactured by LF Engineering Co. is free from defects in material and
wormanship. LF Engineering Co. obligation under this warranty is limited to the
replacement or repair of the product within 1 year from date of shipment. The L-
600 Loop Antenna under the same conditions, is warranted for 90 days.
L-600 Rev. C
Copyright 2007 by LF Engineering Co.
All rights reserved
Printed in USA
