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What is the read range?

tag detection PIT tag antenna tag orientation

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#1 ebridge

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Posted 21 August 2012 - 12:52 PM

Short answer: 2 inches or 5.5 cm

Full answer: It depends on the antenna size, the antenna tuning, the tag type, and the tag orientation. With the low-cost system optimized, I can get reads at 4 inches with a 12mm ampule tag.

Antenna size: Optimal size is probably around 10cm--I'm talking about a round loop antenna here. I've not really tested an array of antennas so I don't know what size is best.

Antenna tuning: The relationship between the antenna inductance and the tuning capacitor is important. But generally being off by a hundred nanohenries does not matter much

Tag type: In general bigger tag antennas give you a much bigger read range. I've not experimented with many tag types, so I cannot provide much insight into how well different tags work.

Tag orientation: seems to matter quite a bit with the PIT tag style tags. Read range is greatests when the long axis of the tag points directly into the antenna loop. So if you are mounting tags on animals, it is best to position the tag and antenna in a strategic way.

#2 ebridge

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Posted 21 August 2012 - 12:58 PM


Maybe. The low cost reader uses an integrated circuit called U2270B to do tag communication. This is a low-power system, which means that read range is limited because of the power applied to the antenna. There is an application note that may allow the read range of a U2270B system to be increased via the incorporation of a preamplifier. You can read the application note here. But read range will still remain on the order of a few inches.

#3 ejackson

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Posted 03 October 2012 - 04:44 PM

I have observed read ranges of 2-4 inches using 8mm PIT tags and antennas that are about 8 cm in diameter. As noted, tag orientation does indeed impact read range significantly - if the tag is not perpendicular to the loop, it needs to be essentially inside the antenna loop (again, this is using 8mm tags). So, depending how you are using the tags antenna orientation is critical. I work with birds, so whether you are putting the tags on leg bands or subcutaneously implanting them can affect your antenna placement (perhaps less so with something like a nest box, where the bird is restricted to one type of passage).

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