2 Meter Slot Cube Antenna Arrl

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52 November 2019.arrl.org QST www Table 1 Yaesu FTDX101D, serial number 9F020045 Manufacturer’s Specifi cations Measured in the ARRL Lab Frequency coverage: Receive, 0.03 – Receive and transmit, as specifi ed, 75 MHz; transmit, 160 – 6 meter amateur including 60 meters on 5.332, 5.348, bands only. 5.3585, 5.373, and 5.405 MHz. I decided it was time to set up a 2 Meter base station. Being the crafty maker type, I wanted to build my own antenna. I settled on a 2 meter vertical dipole. I proceeded to make a very heavy dipole from copper pipe, akin to the type used for J-poles.

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.

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.

OCF Antenna for 40-10 Meters

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.

Cube

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.

2 meter slot cube antenna arrl radio

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.

2 Meter Slot Cube Antenna Arrl Radio

Cubical quad antenna includes:
Cubical quad antenna basicsQuad beam antenna with reflector & director2 metre cubical quad design

The cubical quad antenna lends itself to use at VHF and UHF, and a 2 metre quad or two meter quad is easy to make using a few items that are easy to obtain or may even be available anyway. It should be remembered when considering its use that the quad, when fed at the bottom gives horizontal polarisation.

Construction of the 2 metre cubical quad does not require any specialised tools and can be accomplished using the basic tools available to any radio amateur or short wave listener.

At the outset it as decided to make each element the same size, and then use small electrical stubs to extend or decrease the electrical size of the element. A small short circuit stub makes the reflector inductive, thereby effectively making it longer than the resonant length. Similarly an open circuit stub makes the director capacitive and effectively shorter than an electrical resonant length.

2 metre cubical quad construction

A quad for internal use can be made quite simply by constructing a simple wooden frame. Each element is made up from a cross of available wood approximately 12.7 x 12.7 mm (1/2 by 1/2 inch) wood – it requires tow lengths each, i.e. a total of six for a 3 element 2 metre cubical quad.

The wood is not critical so see what is available and adjust the design to suit. The length of each member of the cross member of the quad is 720mm.

At both ends of each piece of wood a small slot is cut to accommodate the wire. This slot can be cut with a saw, or alternatively it is possible to drill a hole of sufficient size to enable the wire to easily pass through. At the centre cut a section out as shown.

In some ways the slot provides more flexibility because it enables the length of the loop to be altered to tune the 2 metre quad to exact electrical resonance.

2 Meter Slot Cube Antenna Arrl

The next stage is to join and glue two cross members to make the characteristic ‘X’ of the 2 metre cubical quad antenna. The two small sections removed from each cross member should slot neatly together.

2 Meter Slot Cube Antenna Arrl Amateur Radio

Having completed the mechanical construction of the ‘X’ frames, the wire can be added and brought to a small two way terminal block. The wire should be of a reasonable diameter, typically 12 or 14 SWG is good.

The wire is brought to a two way terminal block and secured in this way. The coax or stub can then be attached to the connections in the terminal block and held securely.

The weight of the coax should not be left to be held by the antenna wire, but the coax should be loped and secured to the boom or the mounting pole.

The stubs should be around 7 or 8 centimetres long – their length is not terribly critical, and can be adjusted. The wires can be around 14 SWG and left to remain parallel under their own strength. The short circuit one can use a single section from a terminal block. The position of this one can be adjusted to give the best performance.

The boom for the antenna is made out of two lengths of 25 x 25 mm wood. If necessary the spacing of the parasitic elements can be adjusted with these two lengths of wood acting as a clamp. However once all the adjustments have been made then all the elements should be firmly screwed and glued to the boom.

2 metre cubical quad summary

2 meter slot cube antenna arrl radio

Although in many ways this 2 metre cubical quad design is rudimentary, it is nevertheless one that can be build with a minimum of tools and expertise.The antenna can be adjusted to provide the best performance for the particular situation in case, however it should not be used externally as it is not sufficiently robust to withstand the rigours of the weather. However when used internally it has given a good account of itself.

2 Meter Slot Cube Antenna Arrl Antenna

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