For amateur radio operators working with limited space, especially in urban settings, the RW4HFN balcony antenna offers a clever and compact solution for operating on the 20-meter band. This design is particularly suited for installation on balconies or small terraces, making it ideal for apartment dwellers or those with HOA restrictions.
Living in an apartment or having limited outdoor space doesn’t mean you have to give up on HF operations. This Balcony antenna offers several compelling advantages for the space-challenged ham operator. Its lightweight fiberglass construction makes it easy to deploy and take down, perfect for temporary installations or portable operations. The antenna can be mounted on a balcony, deployed in a park, or set up during field day events with minimal effort.
What makes this design particularly attractive is its simplicity. Unlike more complex antenna systems requiring extensive hardware and permanent mounting solutions, the fishing pole antenna uses readily available materials and can be assembled with basic tools. The wire elements are supported by an inexpensive telescoping fishing pole, which provides the necessary height and structural support without the weight and complexity of traditional antenna supports.
Understanding the Design
The antenna configuration follows a classic inverted-V dipole arrangement, with the fishing pole serving as the central support mast. The design achieves resonance on the 20-meter band through carefully calculated wire lengths and proper matching components.
Key Components and Measurements
Radiating Elements:
- Upper wire element: 3.4 meters with 5.6 microhenry loading coil
- Lower wire elements: Two legs of 6.5 meters and 6.4 meters, connected through an 8.8 microhenry coil
- Feed point height: 1.4 meters above the lower attachment point
Feed System:
- 50-ohm coaxial cable run: 4.4 meters
- RF choke at the feed point for common-mode current suppression
- Fishing pole provides structural support and element separation
Materials You’ll Need
Gathering the right materials is crucial for a successful build. You’ll need a telescoping fiberglass fishing pole, preferably 6 to 8 meters in length when fully extended. Look for one with a sturdy construction that can handle light wind loading. For the wire elements, copper or copper-clad steel wire in the 14 to 18 AWG range works well, offering a good balance between strength and flexibility.
The loading coils are critical components for achieving resonance. You can wind these yourself using appropriate coil forms and enameled copper wire, or purchase pre-made inductors with the specified values. The RF choke at the feed point can be constructed by coiling several turns of the coaxial cable itself, or you can use a dedicated common-mode choke.
Balcony Antenna – Installation Considerations
The beauty of this Balcony Antenna design lies in its versatility. For balcony installations, you can mount the base of the fishing pole to a sturdy railing or use a temporary mounting bracket. Ensure the pole is secured against wind and weather, particularly if left installed overnight or during inclement conditions.
The inverted-V configuration naturally helps with element support, as gravity assists in keeping the wires taut. The lower elements slope downward and can be anchored to the building wall or other suitable attachment points. Try to maintain symmetry in the installation for optimal performance, though the Balcony Antenna will still function reasonably well with some asymmetry due to space constraints.
Balcony Antenna – Performance Expectations
While a fishing pole antenna won’t match the performance of a full-sized beam or large wire antenna installed at optimal heights, it provides surprisingly effective results for its size and simplicity. Many hams have reported successful contacts across continents using similar designs, particularly during favorable propagation conditions.
The antenna’s radiation pattern follows that of a typical inverted-V dipole, with maximum radiation broadside to the wire elements. The relatively low height means the radiation angle will be higher than ideal for DX work, but this can actually be advantageous for regional contacts within a few hundred miles.
Related Posts