Hf Skeleton Slot Antenna



One of the most fun activitiesin Ham radio is learning to build your own equipment. In the early years ofamateur radio, long before factory-built equipment was easily available, Hamsbuilt their own radios and accessories. Why not continue the tradition? Hereare several projects you can easily complete in a few hours or less.

It is true that when a HF field exists across a narrow slot in a conducting plane, the energy is radiated. The image shows a slot antenna, which explains well about its working. Consider an infinite plane conducting screen is taken and pierced with apertures of desired shape and size and this will be the screen of slot antenna. It looks very similar to the skeleton slot antenna design. A vertical slot in a metal sheet radiates horizontal polarised radiation due to the RF current flowing around the edge of the slot. A skeleton slot effectively removes the metal sheet leaving the edges of the slot. In the UK this was originally used for 8 over 8 element TV and amateur.

Two Meter Antenna

It’s likely your first Ham radiopurchase was a 2 meter or dual-band HT. Unfortunately, the rubber duck antennathat came with it isn’t the best choice for maximum signal. If you’re tired of peopletelling you your signal is weak, the simplest remedy is an improved antenna.

You’d be surprised how well this simple vertical antenna works, and it can be built with basic materials: wire and coaxial cable. You can tape it up on a wall or window. For outside use, enclose it in 1/2 inch PVC pipe with a tee in the center and end caps.

Hf Skeleton Slot Antennas

OCF Antenna for 40-10 Meters

Hf Skeleton Slot Antenna Mounting Brackets

Hf Skeleton Slot Antenna

While we’re on the subject ofantennas, you may want an antenna for HF contacts. OCF stands for Off CenterFed, and it’s an inexpensive way to cover 40, 20, and 10 meters while notrequiring a lot of real estate to set up.

The design is based on a simple dipole, with a twist—you don’t feed it at the center, but off-center. All you need is 66 feet of wire, end insulators, and a 4:1 balun such as an LDG RBA-4:1.

DC Distribution Box

The bigger your shack gets, themore power outlets you’ll need. In a typical shack you might have a 100 watt HFradio, a 50 watt 2m FM radio, an antenna tuner, and a QRP rig that all require13.8 volts—and your switching power supply may only have one or twoconnections.

SOTABeams Fuser 6 DC Distribution Boxkits incorporate PowerPole connectors and will let you connect up to five accessories to your power source. For safety, all of the connectors are individually fused and the box incorporates a polarity warning system to help avoid damage to your equipment.

All you need to build one is a soldering iron and solder; wire cutter, and screwdriver. Assembly time is about one hour. A four-way kit is also available.

Dummy Load

When you test radio equipment, you need a way to transmit without interfering with other stations. The Elecraft DL1 Dummy Load Kit is a general purpose, wideband dummy load that lets you perform bench-top testing and alignment before connecting to the antenna. An on-board RF detector allows you to calculate power output using a digital voltmeter.

Power rating for the dummy loadis 100 watts momentary, 20 watts continuous.

Sound Card Interface

Are you interested in digital communications modes? Unified Microsystems SCI-6 PC Sound Card Interface Kits can get you on PSK31, RTTY, WSJT, and other exciting digital modes by utilizing your PC’s internal sound card. Connect to your PC and radio, and make contacts using software such as FLDIGI.

This kit contains ahigh-quality, double-sided circuit board with a solder mask and componentlegends for easy assembly using simple tools. A machined case is included,along with cable for your computer.

QRP Projects

QRP means radio operating with lowpower—typically 5 watts or less. So why would Hams use low power? It’s easy andinexpensive to build QRP radios and accessories—ones you can take just aboutanywhere and operate on batteries.

ARRL’s book More QRP Poweris a project resource including articles from recent issues of QST and QEX magazines. It covers construction practices, transceivers, transmitters, receivers, accessories, antennas, and more. Presented here are dozens of projects and articles to help you assemble or improve a QRP station for home or travel.