RF or AM – Which Electronic Article Surveillance (EAS) system is right for you?

RF or AM EAS system

Used by over 73% of retailers worldwide according to the Global Retail Theft Barometer, electronic article surveillance (EAS) is considered one of the most effective weapons in the war against shoplifting.

Encompassing a series of systems that electronically monitor products via tags and antennas, the two most commonly utilised technologies are Radio Frequency (RF) and Acousto Magnetic (AM) – but how do retailers select the right system for them?

Here is a guide to the differences, attributes and key usage of RF and AM electronic article surveillance.


The basics

All electronic article surveillance works on the same methodology, and you can learn more about it here. But in a nutshell, an item is tagged or labelled and one or more antennas, usually positioned near the store opening, communicates with them when they come into range, alerting store management when someone attempts to remove an item from the store without proper processing.



The key difference between RF and AM electronic article surveillance is the tag/label technology and the frequency at which the systems operate, which is measure in Hertz.  Acousto Magnetic systems operate at 58 KHz, which means a signal is sent out in pulses or bursts between 50 and 90 times a second while Radio Frequency or RF operates at 8.2 MHz.


Radio Frequency (RF) technology, Swept or Pulsed

Historically RF has been considered more affordable to install and often most popular with retailers who use adhesive security labels over security hard tags. The RF electronic article surveillance comprises hard tags or soft labels, and normally one or more pedestal antennas or recently RF in floor antennas. Basically, the tags/labels have tiny circuits that resonate between 7.4 to 8.8 MHz, with the most popular frequency being 8.2 MHz.

Using Swept RF Technology one pedestal acts as a transmitter, sending out a signal.  If an intact tag or label comes into the pedestal vicinity, it will resonate and this is detected by the second pedestal acting as a receiver. An alarm will then sound. Using Pulsed RF Technology, a single pedestal antenna both sends and receives the signal, sounding an alarm when a tag is detected within the detection range. Multiple swept or pulsed pedestals can be used, depending on the width of the doorway being protected.

Tags and labels range from a wide range of small ultra-thin adhesive labels through to a variety of hard tags, and are suitable for a variety of applications, including clothing, food and pharmaceutical products.

Labels are deactivated by using a Label Deactivator to overload the integrated capacitor to effectively break the label’s circuit, while hard tags are removed at the point of sale normally by a powerful magnetic security tag detacher.

Probably due to its traditional lower price RF remains the most widely adopted EAS technology worldwide. RF is often favoured due to the flat footprint of its paper labels that make it suitable for high volumes of packaged products, and for the easy integration of Deactivation into Point of Sale Scanners.

Although RF EAS is not to be confused with RFID. Some RF antennas can easily be upgraded to RFID where RF and RFID technology work side by side in the same antenna.

RF does have limitations, however. The technology has traditionally been more sensitive to interference from electrical interference caused by other local electronic fixtures that often don’t affect other EAS technologies. Although in the real world it’s not a problem but RF Security Labels cannot be reactivated once the circuit is broken and detection systems are generally limited to doorway pedestals, although recently some RF floor based systems are being seen in the market.


RF Benefits at a glance

  • Affordability: Price can range from very low cost for more basic RF systems to high cost for advanced RF systems.
  • Available as flat paper labels
  • Wide range of label shapes, sizes and presentation
  • Labels can be printed on
  • Potential for upgrade path to RFID with some RF antenna systems
  • Easy high speed security label deactivation including possible integration with POS scanners
  • Available from many manufacturers

RF Disadvantages

  • Labels cannot be reused once the circuit is broken
  • Limited range of detection systems traditionally limited to pedestals
  • More susceptible to electronic and metallic interference

Who uses RF EAS

  • Often suited to retailers with high volumes of packaged products.
  • Most popular with supermarkets, discount stores, chemists and video stores.
  • RF has seen recent growth in apparel stores.

Acousto magnetic (AM)

When AM was developed it overcame some weaknesses found in previous EAS technology. AM electronic article surveillance offers an extended detection range to RF and is normally less susceptible to interference from external electronic interference. This provides greater flexibility for installation of the antennas, which can be pedestal based or can be concealed within door frames or under the floor at the entry of the store. AM adhesive security labels can often work on or near metals where other technologies fail.

AM works on the principle that a transmitter sends out a signal in bursts which energise tags within the pedestal zone. When the pulse ends, the tag responds. Between bursts, the tag’s signal is detected by a receiver. Therefore, if an active tag passes between the pedestals, an alarm will sound.

Like RF, hard tags are available in a range of sizes, and can be reused. Although smaller than RF labels AM labels are not paper thin and have a raised profile. Labels can potentially be deactivated and reactivated, though this is not common practice. They are activated when magnetised and deactivated when demagnetised.

AM has traditionally more expensive to install than RF, however due to increased competition system costs have come down in recent years. AM is more often seen in small to large clothing apparel chains, DIY, Electronic  and some department chains stores.

AM Benefits at a glance

  • Larger detection area so Antennas can be positioned further apart
  • Less susceptible to electronic interference
  • Systems can be concealed in door structures or under flooring
  • Security labels can be reused and reactivated
  • Accurate detection of tags and labels

AM Disadvantages

  • Often cost is higher than RF
  • Labels cant be bent around merchandise and can’t be easily printed on
  • Antennas not easily upgradable to RFID

Who uses AM EAS

  • Large department stores
  • Apparel stores
  • Hardware stores
  • Retailers selling products with metallic and foil components or packaging

Final roundup

Selecting the right system for a retail environment is a weigh-up of the retailer’s intended usage and needs. Ultimately, it will depend on the budget and size of the store along with the type and volume of products the system will protect. Do your homework and talk to suppliers and understand your needs and what you want to protect. Also consider your store layout and the impact EAS will have on it. If you are unsure and time and budget allows get the supplier to install trial systems to see what technology works best for you.