What to consider when sourcing an Antenna!
There are a multitude of factors to consider when sourcing a commercial antenna. Firstly and most importantly is the frequency band. If the antenna is not working efficiently at the desired frequency then much of the transmitted signal will be reflected back from the antenna, rather than radiated from it. This reflected power, not only is wasted energy, but potentially can cause damage to the transmitter. Likewise, in the receive path, a poorly matched antenna will not pass signals efficiently to the receiver, thus degrading system performance.
Another consideration is the radiation pattern of the antenna…do you need full 360-degree (omnidirectional) coverage or do you only need to guide your signal to/from a fixed coverage area? Your radio licence may also dictate a particular type of antenna required so you will need to make sure you comply with these requirements first and foremost.
Antenna gain is an often miss-quoted and misunderstood factor - suffice to say that, in a passive (non-amplified) antenna, any gain that is on offer is generally at the sacrifice of the signal transmission/reception pattern. If this works in your favour then great ie. a directional antenna focusses the signal in a particular direction only with little or no performance outside this coverage area, so you get high gain but only in one direction. For an omnidirectional antenna with gain, you are simply squeezing the signal into a flatter horizontal pattern aimed at the horizon.
Quality of construction is another important factor - in these modern times antennas have to be installed professionally (health & safety dictates that you can no longer shimmy up a tower or clamber around a roof yourself) and these installation costs can often be more than the antenna itself. You do not want to be having to replace the antenna for many years to come.
All antennas are made to a price point based on quality of components, engineering and production costs. The saying "you only get what you pay for" is most apt here and it is often a false economy to choose a low-end budget antenna for your radio system. Not only will your radio system not be working to its optimum but you could find that you will be paying for another antenna (plus riggers fees etc.) in a few year's time to replace the antenna once it has failed or is providing poor performance. If you owned a sports car, you wouldn't put the cheapest tyres on it - that piece of rubber transfers the performance of the car to the road equating in handling, grip & braking power. A radio system will only work as well as the antenna system that is connected to it.
antennaPRO distribute a wide range of professional antenna products for the Amphenol Private Networks throughout the UK and Ireland. If you have a requirement for antennas, contact our team on +44 (0)1227 743099 or via email at firstname.lastname@example.org