Multiple Antennas Or Multicoupling - What Should You Use?
Separate transmit and receive antennas, or a single antenna for Tx and Rx using a duplexer?
In most cases, the use of separate Tx and Rx antennas is preferred. In using separate antennas, you can take advantage of free space isolation rather than use expensive filtering equipment, site additions can be easily carried out through multicoupling and where this is done multiple bases can utilise the best placed antennas.
However, the use of separate antennas is not always possible especially when you are locating on an existing tower. Tower space may not always be available, and on prime sites is generally expensive. These factors may dictate the use of a single antenna. Feeder costs must also be considered, especially at UHF and 800 MHz frequencies where larger and more expensive cables are used to minimise losses.
In instances where only one antenna is available a duplexer is required to provide the necessary isolation. There are many duplexers available including notch, vari-notch, bandpass and combination types. The choice of duplexer is critical and one must consider potential interference from other co-sited bases when making the decision.
On a crowded site multiple bases may even make duplexers impractical. At this point multicoupling should be considered which in most cases involves redesigning the tower around - you guessed it - separate Tx and Rx antennas, and utilising that free space isolation. Duplexers, and even more so multicouplers are commonly misunderstood and overlooked parts of many radio systems today. Interference can result simply by making incorrect choices.
For advice on the right equipment for your site - talk to our site management engineering team.
Silver oxide is the only oxide (that we know of ) that is conductive. This is one reason why PolyPhaser’s N-type coax connectors are all silver with gold centre pins. Copper oxide is not conductive and the proper application of joint compound will prevent oxidation.
Knowledge of corrosion can make the difference between a good site that stays on the air and one which needs a lot of maintenance after a short period of time.
…This tech tip courtesy of PolyPhaser Corporation newsletter "Striking News"
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