P
High-Band (Millimeter Wave) 5G Antennas —
Very tiny, used by 5G cellular devices operating
near 30GHz (10mm).
Q
ALLISS — Commercial, government, and
high-power shortwave stations with coverage
that needs to be changed directionally may
use giant, steerable ALLISS antennas (from
the French towns of Allouis and Issoudun).
R
“Elephant Cage” (AN/FLR-9, AN/FRD-10) —
During the Cold War, massive ring antenna
systems were set up to monitor and locate
radio transmissions worldwide. The last of
these “elephant cage” antennas can still be
seen in Canada and Alaska.
LOOP
Unique in that many of them respond to the
magnetic rather than the electrical portion of the
electromagnetic waves. Have very sharp nulls,
making them useful for direction finding. Very
portable; common in receivers and low power
(QRP) operations.
S
Circular — Loop antennas can be circular,
rectangular, or any closed geometry. They
are often easier to deploy than large wire
antennas.
T
Quad — Loop antennas can also include
multiple elements that modify their directional
transmission and reception abilities.
U
Radio Direction Finding Loop — Radio direction
finding (RDF) usually uses small receiving
loops that are inefficient for transmitting, but
have extremely sharp nulls to assist in finding
the direction of a radio source.
Wikimedia Commons: Bidgee, Tony Webster, Kingbastard, Joe Ravi; Flickr - Endolith, Make Magazin DE
David Baillot/UC San Diego Jacobs School of Engineering; Wikimedia Commons: Eyreland, Chaddy, Trixt, Daderot; with permission Randy Taylor, WB5QFM
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M78_112-21_SB_Antennas_F1.indd 121M78_112-21_SB_Antennas_F1.indd 121 7/10/21 3:01 PM7/10/21 3:01 PM
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