In this article I will define with a brief explanation each of the main elements when implementing an RFID project. When an RFID chip crosses the antenna field, it is activated and emits a signal. The antennas create different wave fields and cover different distances. Antenna Type : Circular polarization antennas work best in environments where the orientation of the tag varies.
Linear polarization antennas are used when the orientation of the tags is known and controlled and is always the same. Overcast angle and gain : Using antennas with gains of between 8.
The more overture the antennas have, the less detection distance. Number of Antennas : Standard high-performance readers have 2 ports, 4 ports or 8 ports. The number of antennas is usually chosen according to the reading space we want to detect or the density of tags to read. Typically used is 2 or 4 port fixed readers. Some brands have multiplexers that allow us to connect up to 32 antennas in the same reader. To choose the right reader, we have to take into account several factors:.
Reading area : Fixed readers serve mainly to cover a specific area: one point by a doorway, a machine, on a conveyor belt, in a crate, etc. The repeater, which previously collected the signal on 31 to 38 or 71 — 78 , then switches to its output channel 1 to 8 and 41 — 48 to transmit simultaneously to say another radio user on the other side of the hill.
Repeater Station locations An interactive listing of all licensed Australian UHF radio repeaters, that can be searched by clicking on a location on a map, by town name or postcode, by call sign or by state. Site users can update the current operational status, and link to maps of the repeater locations are provided. Below you will find a list of UHF Radio channel allocations. There are many channels that have been established by law including the Emergency channel 5 and the data transmission channels 22 and The new 80 channel system does not change the allocation use of these channels.
This chart is also available for download free from our online store. This channel, which is established by law, is used to call or locate another station. Voice transmissions are not allowed on these two channels 24 — 30 Used for conversations.
Note Channel 29 is specifically as a road channel. Press the duplex button on your radio to use any available repeaters. Telemetry Systems This technology is used for the transmission of data. By utilising telemetry systems via UHF signals, farmers can remotely control the operation and function of various types of equipment such as electric fences, water pumps and dam levels from many kilometres away. Use a poor antenna or mount the antenna is a bad location, will greatly reduce your range and clarity.
However depending on where you mount your antenna, will affect the way the antenna radiates. The best location for an antenna is in the middle of your roof however this is generally not practical. Antenna are normally mounted the guard or bull bar. This these cases, it is essential that you A use a ground independent antenna see Ground Independent Antenna for more information , B mount the antenna away for vertical metal section like windscreen pillars etc. Following these suggestions will help minimise any affect on the radiation pattern.
As gain is increased, the radiation gets compressed into a thinner pattern and reaches out further to the side. The more gain an antenna has the thinner the pattern becomes and the further the signal can travel or reach.
If necessary, you can get a portable, mobile or base antenna compatible with those frequencies, giving your radio better range. Find them online or at electronics stores. UHF antennas are generally quite short because an efficient "quarter wave" antenna measures around six inches long.
Turn on the radio and choose a channel. Turn the tuner selection on your radio. The UHF channels are 12 kH apart from each other and can be found by turning your channel selection dial. Your device might instead have buttons to select up and down channels.
The public UHF radio band is divided into 50 to 80 channels, depending on your area. For example, tune into Some radio receivers have a "squelch" or "quiet" control, which can be adjusted to limit the noise caused by interference from weak signals. Adjust the squelch until you hear very little noise, or only strong, local transmissions.
Push the transmission button to talk. Anyone who has seen a walkie talkie will have an idea of how to operate a UHF radio. Wait for others on the channel to stop talking, if you hear any. Press down the transmission button, often found on the side of the unit.
Speak into the microphone, which can be found on the face of a handheld radio or on an attached speaker-microphone headset. On larger radios, use the handheld microphone attached to the radio by cord, and its transmit button.
Anyone tuned to that channel will hear. By letting go of the button, your radio stops transmitting and returns to the receive mode. Follow proper radio etiquette. A large part of etiquette is being polite. Invent a unique call sign, which can be anything you want besides your name.
Use call signs to respond to others and state yours every ten minutes or so to check if your radio is still in range of others. Keep your sentences clear and to the point. Learn the international phonetic alphabet Alpha, Bravo, Charlie, etc.
Some channels are reserved for specific uses by law or by convention. Why you need a high-power HF transmitter. Previous News. Next News. Subscribe Register For Barrett news and updates Register. This website uses cookies to improve your experience. We'll assume you're happy with this. Accept Read More. Close Privacy Overview This website uses cookies to improve your experience while you navigate through the website. Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are as essential for the working of basic functionalities of the website.
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