Hi, I was looking at this item, https://www.sparkfun.com/products/14131, and was wondering if using two of these guarantees that if ONLY SOMETHING PASSES BETWEEN two of these that a signal would be registered by both at the same time. I guess this may be a directional vs. omnidirectional question. I would NOT want something passing outside the two readers and both of them registering a signal at the same time. Only when an item passes between them would a signal be registered by both at the same time.
What type of distance and coverage can it detect an rfid tag?
This antenna is somewhat directional but we don’t have a radiation pattern diagram for it.
I can say from experience, the antenna is most sensitive directly in front and not sensitive at all from behind.
There could be some side lobes where a tag not directly in front of the antenna can be detected and you might be able to detect a very nearby tag on the sides of the antenna.
Using two wouldn’t positively guarantee that only a tag between them would be read, but by using multiple readers and the right processing, you’d make it more likely that you’d only read tags passing between the antennas.
It’s important to remember that this is just an antenna and on it’s own, has no range. It’s the combination of reader, antenna, and how much power the reader transmits with and the tags in use that ultimately determines range. Additionally, the type of tag you’re using and how and what it’s mounted too will influence rage. You’d need to experiment with your local conditions to determine range but we’ve been able to get up to 16 feet of range with [our tags using [our reader and this antenna under ideal conditions. Your results may vary depending on the conditions where you’re testing are.](https://www.sparkfun.com/products/14066)](https://www.sparkfun.com/products/14151)