Summary of Frequencies
125 KHz LF (low frequency) Passive
First put to use commercially in the 1980’s (generally), most all systems today are based on 125 KHz however there is an ISO standard (11784 & 11785) based on 134.2 KHz used in the animal market. Our first frequency was 148 KHz and other vendors had their own as well. Most LF applications consist of read ranges from inches to a foot, although 1 meter of distance is possible but requires a large Tag and Reader Antenna.
- LF Advantages – Tags on/in metal, Readers in close proximity to one another without interference, Tag speed.
- LF Disadvantages – Tag memory size generally limited to 2k bits, Tag cost prohibitive for applications requiring millions of Tags, although anti-collision capable there are not many applications where hundreds of Tags are to be stationed within a foot. Click here to download a tutorial PowerPoint with application photos and view a video of Tag read speeds with networked Smart Antenna Readers.
13.56 MHz HF (high frequency) Passive
HF came of age in the late 1990’s as an answer to lowering Tag costs in order to address high volume Tag applications such as library books, laundered items, passports and credit cards to mention a few, as LF Tags contain a hard copper coil and are difficult to mass produce while HF Tags can use printed metals or metallic fluids as a Tag coil. Read ranges are similar to LF, most applications are inches to a foot, although 1 meter f distance is possible with a large Tag and Reader Antenna. HF did not take off into the hundreds of millions of Tags application as predicted but is still a solid choice for some applications.
- HF Advantages – More Tag memory, slightly less cost per Tag in volume than LF.
- HF Disadvantages – On metal mount or heavy metal environments, can be done but is finicky. Readers in close proximity will interfere with one another. Although anti-collision capable there are not many applications where hundreds of Tags are to be stationed within a foot. You may see a lot of vendors tout 13.56 MHz as being ISO standard. In general Tags are ISO standard, however you are still locked into a single vendor as Readers vary greatly from vendor to vendor and sometimes Tags are programmed with proprietary data.
433.92 MHz UHF (ultra high frequency) Active (some vendors offer 2.45 GHz Active with the same features detailed here)
Battery powered Tags have always been around but their applications are limited and very specific.
- Active Tag Advantages – Read range of thousands of feet, the ability to tune to a specific read range, and anti-collision feature (the ability to read more than 1 Tag at a time).
- Active Tag Disadvantages – Tag cost ($20 to $30), Tag size, finite battery.
868 to 928 MHz UHF (ultra high frequency) Passive
Generally known in the USA as 915 MHz or just “UHF”, each country or continent has its own specific frequency that is accepted by regulating authorities. For a list of those, see this GS1 document here (attachment). Since the early 2000’s, 915 MHz has been all the rage, the vogue technology of frequent press bringing the RFID industry into a global limelight, the epicenter of development efforts and dollars. Tags at this frequency also need not incorporate a hard copper coil, promising the least expensive RFID Tag to address high volume applications however Tag innovation and development did not bring the frequency to competitiveness until about 2006.
- UHF Advantages – Read Range up to 90 feet, Tag cost, anti-collision feature, and truly being ISO standard across vendors.
- UHF Disadvantages – Reader cost, range performance limited or even enhanced by liquids (like the human body), metal can be a friend or enemy depending upon the Tag chosen.