Spiral Antenna Designs and Construction Projects
Find resources and projects for building and experimenting with compact spiral antennas for various ham radio bands and applications.
Spiral antennas offer a compact solution for operators needing to fit HF antennas into limited spaces, such as small backyards or apartment patios. These designs often achieve multi-band operation, allowing hams to work several bands with a single, physically small antenna. Their unique winding geometry can provide wide bandwidth, making them useful for various amateur radio activities from casual QSOs to portable operations.
Hams experiment with different spiral antenna configurations, including spiral dipoles for bands like 20 and 40 meters, as seen in designs by KN9B and K6NO. Many projects focus on adapting these antennas for portable HF use or for specific applications like software-defined radio (SDR) reception. Operators can find resources detailing construction techniques for compact multi-band HF dipoles and even Archimedean spiral antennas, often evaluating their SWR response and overall performance.
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An attempt to modify and try out the unusual antenna first described by Bill Petlowany, K6NO, in World Radio Magazine -
WorldRadio Article on Petlowany antennas base on this principle: if a length of wire is wound into a spiral-shaped coil and excited by a radio frequency current connected to the innermost portion of the coil, it will then, and only then, exhibit RF characteristics that closely approximate those of a resonant linear wire of the same length -
Experiments with spiral dipole antennas. Includes two spiral antenna designs for 20 and 40 meters band by KN9B -
A New Twist on Portable Multiband HF Dipoles, a Multi-band Spiral Dipole Off-Center-Feed match (OCF) antenna solution. -
An experimental antenna similar to the TAK spiral antenna was evaluated for SWR response over the frequency range of 7.0 to 7.3 MHz, or the 40-meter band. -
Dodgy plans to make Archimedean spiral antenna for RTLSDR software defined radio receiver. Made of two equal lengths of coaxial cable seems to be the easiest circularly polarized antenna to make that will cover a broad range of the rtlsdr dongles E4000 tuners -
A spiral antenna experiment for RTL SDR usage. -
Designing and Testing a PCB Wideband Spiral Antenna. The 800 MHz+ and 300 MHz+ spiral antennas by Hexandflex -
Explores spiral antenna theory, including Log-Periodic and Archimedean types. Covers design parameters, radiation patterns, and construction. -
This antenna is an off-center fed spiral dipole for 40 meters. The spiral dipole is very compact, making it well-suited for limited space (like an apartment patio), while the off-center feed gives the antenna some multiband capability.