I am trying to build an RFID system to track animals. I am using 125 Khz glass capsule tags by Sparkfun implanted under their skin. I initially used an ID-12LA reader, but I am not getting reads most of the time, possibly due to tag angle, tag orientation, read range...etc.
I am moving on to an ID-3LA in order to utilize its external antenna capabilities. This reader requires an antenna producing 1.337 mH. So, I bought a 46 mm antenna capable of producing 2.8 mH. I connected the system as follows:
but unfortunately, I am unable to get reads at all.
Here are my design/troubleshooting questions:
1) In general, if I have an antenna capable of producing inductance higher than that required by the reader, will this compromise the system? If so, what are ways to reduce inductance (without having to remove turns)? According to my research from previously asked questions on this website: people spoke of adding a capacitor to increase inductance but I haven't seen anyone speak of decreasing inductance. Are there any tricks using resistors...etc.?
2) Is there a physical limitation in my system: small tag, antenna with small diameter, read range of 46 mm (or in other words read range inside the circular antenna)? Am I possibly activating the tag, but unable to read it back because of the magnitude of its "identity signal"?