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- Antenna Basic Terms
Hf Skeleton Slot Antenna Combo
- Types of Antennas
- Antenna Arrays
- Wave Propagation
- Antenna Theory Useful Resources
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- About HF Skeleton Slot Antennas The resource is currently listed in dxzone.com in a single category. The main category is Skeleton Slot Antenna that is about Skeleton Slot Antenna. This link is listed in our web site directory since Friday Nov 27 2020, and till today 'HF Skeleton Slot Antennas' has been followed for a total of 2 times.
- . The skeleton slot antenna for 144 MHz by VK5XU and VK2NO (April 1955, p2). Some considerations in the selection of an antenna tower by W4QDZ (April 1960, p 8). The HB9CV Swiss Quad by VK6DR (April 1965, p6). The corner antenna for 7 MHz by VK2SA (April 1967, p7). The ferrite balun by ZS1SC (April 1969, p9) PS: Want to read newer items on.
Slot Antenna is an example of Aperture antenna. A rectangular slot is made on the conducting sheet. These slot antennas can be formed by simply making a cut on the surface, where they are mounted on.
Frequency Range
The frequency range used for the application of Slot antenna is 300 MHz to 30 GHz. It works in UHF and SHF frequency ranges.
Construction & Working of Slot Antennas
As a re-design of this familiar tall skeleton slot, seen widely on the internet, it incorporates significant improvements noticed during the design of a related antenna, the HF kite-shaped slot antenna, QST, July 2019. Changes to the Hentenna. It became obvious with the kite antenna, a near.
The use of slot antennas is well understood through its working principle. Let us have a look at the structure of a slot antenna.
When an infinite conducting sheet is made a rectangular cut and the fields are excited in the aperture (which is called as a slot), it is termed as Slot antenna. This can be understood by observing the image of a slot antenna. The following image shows the model of a Slot antenna.
The working of Slot Antenna can be easily understood through Babinet’s principle of optics. This concept gives an introduction to the slot antennas.
Babinet’s Principle
Babinet’s principle states that- “When the field behind a screen with an opening is added to the field of a complementary structure, the sum is equal to the field when there is no screen”.
The above images clearly explain the principle. In all the regions, which are non-collinear with the beam, the above two screens, in figures 1 & 2, produce the same diffraction pattern.
Case 1 − Consider a light source and a conducting plane (field) with an aperture before a screen. The light does not pass through the opaque area, but passes through the aperture.
Case 2 − Consider the light source and a conducting plane of the size of the aperture in the previous case, being held against the screen. The light does not pass through the plane but through the remaining portion.
Case 3 − Combine these two conducting planes of both the cases and put before the light source. The screen is not placed to observe the resultant combination. The effect of screen gets nullified.
Working of Slot Antenna
This principle of optics is applied to electromagnetic waves for the wave to get radiated. 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. Another screen is considered interchanging the places of aperture and screen area which is the complementary screen.
These two screens are said to be complementary as they result in complete infinte metal screen. Now, this becomes the slot antenna. The terminal impedance is quite desirable for the radiation.
Radiation Pattern
The radiation pattern of the Slot antenna is Omni-directional, just like a half-wave dipole antenna. Take a look at the following illustration. It shows the radiation pattern of Slot antenna drawn in Horizontal and Vertical planes respectively
Advantages
The following are the advantages of Slot antenna −
- It can be fabricated and concealed within metallic objects
- It can provide covert communications with a small transmitter
Disadvantages
The following are the disadvantages of Slot antenna −
- Higher cross-polarization levels
- Lower radiation efficiency
Applications
The following are the applications of Slot antenna −
- Usually for radar navigational purposes
- Used as an array fed by a wave guide
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.
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.
Hf Skeleton Slot Antennas
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.
Hf Skeleton Slot Antenna Receiver
Dummy Load
Hf Skeleton Slot Antenna
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
Hf Skeleton Slot Antenna Mounts
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.
Hf Skeleton Slot Antenna Mounting Brackets
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.