Q: FDX or HDX tags?
A: The tag protocol should match the protocol of the reader/decoder. FDX-B tags are regarded as faster reading and smaller form factor than standard HDX tags, though this isn’t necessarily the complete picture (see our Barracuda systems). HDX tags can be read over larger distances
Q: What sizes of glass encapsulated PIT tags are available?
A: WMD supply FDX-B, predominantly 7, 8mm or 12mm. Our HDX tags are available in 12, 13, 22.5, 23, and 32mm and other protocols and specifications are also available
Q: What size of tag is best?
A: Tag size should be related to size of animal/fish/bird/invertebrate being tagged. One-size-fits-all is a bad way of buying tags. A salmon smolt may be suited for a 12mm tag, but an adult fish should be tagged with a 32mm tag, since the larger read range reduces the chance of a fish not being detected. A well designed project will determine the range of fish/animal sizes and buy a tag selection accordingly, thereby reducing uncertainty in data and maximizing detection opportunity. A good rule-of-thumb is to use the largest tag possible that is <3% of the fish/animal’s weight and will comfortably fit within the animal/fish etc. Using tiny tags in large animals just hampers studies and reduces effectiveness of detection equipment
Q: Are all tags basically the same?
A: Yes and No. Yes, in that the principles of design are broadly similar and No, in that the quality of materials and construction, # of windings and IC’s and tag protocol may differ considerably, influencing read rates and range
Q: Antenna size, how large?
A: FDX systems are constrained by the size of their antennae, thus usually used in confined locations and spaces such as smaller fish passes. HDX systems suffer less from antennae size constraints, generally being able to be made larger in both diameter and length than FDX systems. Typical self-build HDX antennae are > 1m x 10m. Pre-built and professionally installed antennae can be much larger than this. Horizontal (flatbed), pass over antennae are usually pre-built and professionally installed. WMD offer standard sizes of horizontal 2,3,5, and 7m, with custom sizes on request
Q: What is the difference in read range of horizontal vs vertical antenna construction?
A: Vertical antennae have greater read ranges since the magnetic field can project both side of the antennae effectively doubling the read range of a horizontal antenna which is constrained by the ground/riverbed on one side. Furthermore, when deploying horizontal antennae, the tag (if inside fish) is usually parallel to the antennae which reduces read range when compared to perpendicular. Having said that, WMD have read ranges of >1m vertical on some horizontal antennae
Q: Are antennae easy to build?
A: Self-build is possible for HDX systems where read range and rate are not important and the environment is not complex, though big improvements can be gained from a professional build and installation. Self-build antennae usually consist of a single cable of multi-strand wire creating a loop, hoop or rectangular aperture. These are pass through antennae. FDX antennae are more complicated and are usually professionally built and installed
Q: How many antennae can a reader power?
A: That depends upon the system being deployed. Conventional HDX Multiplexing systems usually operate 2-4 antennae, though in practice it’s better to only use 2 antennae per reader due to loss of read rates. Maintaining native read rates usually requires operating multiple readers. This is pertinent when working with fast moving species. The WMD Barracuda system can power > 64 antennae without loss of read rate, though typically supplied with 8-16 antennae
Q: Can I cover a 20m wide river with PIT tag antennae?
A: Yes, though it’s recommended to use a series of antennae strung across the river to form an antenna array
Q: How can I cover a deeper (~1.8-2m) section of a river ensuring fish are detected?
A: A combination of our WMD Flooded Horizontal swim over antennae and floating horizontal antennae may be deployed simultaneously to provide coverage without the entrainment issues on large swim through antennae
Q: How do I tune my antennae?
A: either by using manual tuners with jumpers to select capacitor banks or by using one of the Digital Dynamic Auto tuning Units like the WMD DDATU. We stock standard and Fast tune tuners and Submersible S-DDATU versions are also available
Q: What reader is right for my project?
A: That depends upon the project. WMD HDX Custom MUX reader is capable of interrogating two separate antennae at half native read rate or driving one single antennae at full read rate, giving the project operator maximum choice and flexibility. WMD HDX Field reader is suitable for powering one large, long-range antenna at full read rate. If fast read rates are important (ie migrating salmonids) then our new ultra fast systems such as the WMD Swordfish technology is an excellent choice. The World’s fastest reader is capable of reading faster than any other LF system. Where fast HDX read rates are important then WMD Barracuda technology would be the system of choice
Q: Can I use mobile detecting of pit tagged animals/fish or structures?
A: Yes, WMD Walker Wands were designed precisely for this purpose. With articulated search heads and on-board information module these mobile detector/readers are used for fish, animals and geomorphological studies involving passive transport and erosion quantification as well as searching for dropped tags under predator areas as a way of determining predation effects
Q: Can I scan tags prior to use for constructing a project database?
A: Yes the WMD Tag verifier will scan directly into any software package of your choice and is self-powered via USB. Just connect a laptop and go! WMD proximity scanners are also available such as the multi-protocol MP Handheld readers
Q: Can anyone tag animals, fish or birds?
A: No. In the UK this procedure falls under the Animals (Scientific Procedures) Act 1986, administered by the Home Office. WMD can provide this service. There are exceptions relating to management of animals welfare and external tagging, but these would require checking before undertaking any procedures
Q: Can solar power be used with charge controllers for powering a RFID reader system?
A: Yes, though not all solar charge controllers are compatible due to noise interfering with operation and affecting read range, detection ability etc. WMD charge controllers have been designed and tested to be suitable for RFID application
Q: Is it necessary to use a charge controller or can just solar panels be wired into the battery?
A: No solar panels cannot be wired direct. It is poor practice to wire directly into batteries from solar source and would result in poor performance and charge maintenance of the battery bank. Without regulation the batteries would overcharge causing failure
Q: What size battery/batteries are required for a RFID system located in the field?
A: That depends upon the system, size of the system and system setup, antennae size and construction. For larger HDX based systems 2 x 130 amp/h SLA batteries are a good starting point. Our terrestrial multi antennae systems are capable of running of very small batteries when under low power mode
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Note: WMD provides the content of these pages for general information purposes only and state that they do not constitute ‘advice’. WMD recommend visitors seek the advice of an appropriately qualified professional before undertaking any RFID installation activity. Please refer to our Disclaimer page for further information.