15-1
Chapter 15
Antennas
Introduction
The 4322 Cotag Reader module uses the Cotag hands free reading
system and therefore requires antennas to switch on Cards and
receive the codes contained in them. This chapter describes all the
available options and how to choose the best one for a particular
application. If you decide to use a loop antenna, you need to read the
Loop Antenna Installation Handbook HB02/106 for details of how to
choose, design and install your loop antenna.
Antenna summary
Reading Heads
There are two proprietary antennas (called Reading Heads)
manufactured by Cotag.
The 090 is smaller than a typical pack of cigarettes (80mm high x
40mm wide x 13mm deep) and contains a transmit antenna, a receive
antenna, signal conditioning circuits, and red and green LEDs which
can be used to show when the door is unlocked. It gives a typical
range of 30cm when used with a 928 Card.
The 280 is approximately the same frontal size as an A4 sheet of
paper (260mm high x 220mm wide x 25mm deep) and contains a
transmit antenna, a receive antenna, signal conditioning circuits, and
three LEDs: red, amber and green. It also contains a horn which can
be connected to the local warning output provided by the 4322 Cotag
reader module. The red and green LEDs are used to show when the
door is unlocked. The amber LED has various indications for faults,
noise, etc. The 280 gives a typical range of 90cm when used with a
928 Card.
Loop antennas
Alternatively, by using the 270 Loop Coupler you can make your own
loop antenna using ordinary single core wire.
The simple door loop is a single loop of wire which combines both
the transmit and receive functions. It can give a wider and deeper
reading area than a 280 Reading Head providing the site in which it
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