Antenna Systems
Our antenna systems are categorized as fixed and portable. All fixed antennas are located on an antenna farm at our observatory and are described on this page. They are used with the fixed receiver installations described here. The portable antennas generally are whip antennas of varying lengths and configurations used with ELF and VLF receivers. Click here for a description of our portable antennas and click here for a description of the receivers used with them.
Antenna Farm
The antenna farm includes a variety of technologies:
- Active loop antenna (150 kHz to 30 MHz)
- Active whip antenna (100 kHz to 30 MHz)
- Beverage antenna (~100 kHz to 30 MHz)
- Discone antenna (~100 MHz to 1 GHZ)
- Large Octagon Loop antenna (3 kHz to 150 kHz)
- HF log periodic antenna (18 to 32 MHz)
- VHF/UHF log periodic antenna (144 to 500 MHz)
- Long-wire antenna (200 kHz - 30 MHz)
- Yagi antenna (~20 to 21 MHz)
Click here for an antenna transmission line connection diagram. The transmission lines from each antenna are fed to a central location where the shields are bonded to earth ground at a grounding block.
The grounding block is made from two CATV-type grounding
blocks.
They are bonded to the earth electrode system by 12 AWG copper
wire. The brown coloring on the lower two connectors is 3M™
Scotchkote™
to seal against moisture. The common cable from
the
antenna relay
box is on the lower connector (4). The upper three
connectors are
used by the Discone Antenna (1), Loop Antenna (2),
and Active Antenna (3). A rain shield is mounted just above the
grounding block.
