Harmonic radar technology can be used to track the dispersal of tagged insects. The tag consists of a wire antenna attached to a Schottky diode, which uses the original radar signal as an energy source, re-emitting a harmonic of the transmitted wavelength. Two forms of harmonic radar use this basic technology to study insect movement. The more sophisticated form consists of a ground-based scanning radar station that tracks the movement of a tagged insect on a circular radar display. A simpler, "off-the-shelf " form of harmonic radar is a commercially available, light-weight, handheld transmitter/receiver from RECCO Rescue Systems. We briefly review both of these forms and describe our experience monitoring the movement of carabid beetles in agricultural habitats with the handheld transmitter/receiver. We identified a commercial source of diodes compatible with the RECCO transmitter/receiver and tested several diode and wire combinations. We found that a tag built with a diode attached to a single section of 8-cm wire (monopole) was more appropriate for marking carabids. Tags built from flexible Teflon-coated wires were an improvement on tags built with stiff, aluminum wire, but beetle movement was still hindered. In corn and soybean fields, large carabids (Scarites quadriceps Chaudoir and Harpalus pennsylvanicus, (DeG.) Coleoptera: Carabidae) could be recaptured even when they burrowed out of sight 3 to 9 cm below the soil surface. We discuss the trade-offs between tag detection and durability that occur when designing a tag for a given organism. Although the technique shows promise, producing a tag that does not hinder movement of the target insect in the field will require further development.
RightsThis article is the copyright property of the Entomological Society of America and may not be used for any commercial or other private purpose without specific permission of the Entomological Society of America.
ABSTRACT:Harmonic radar technology can be used to track the dispersal of tagged insects. The tag consists of a wire antenna attached to a Schottky diode, which uses the original radar signal as an energy source, re-emitting a harmonic of the transmitted wavelength. Two forms of harmonic radar use this basic technology to study insect movement. The more sophisticated form consists of a ground-based scanning radar station that tracks the movement of a tagged insect on a circular radar display. A simpler, "off-the-shelf" form of harmonic radar is a commercially available, light-weight, handheld transmitter/receiver from RECCO Rescue Systems. We briefly review both of these forms and describe our experience monitoring the movement of carabid beetles in agricultural habitats with the handheld transmitter/receiver. We identified a commercial source of diodes compatible with the RECCO transmitter/receiver and tested several diode and wire combinations. We found that a tag built with a diode attached to a single section of 8-cm wire (monopole) was more appropriate for marking carabids. Tags built from fle...
A multiple substrate, microwave plasma-assisted chemical vapor deposition synthesis process for single crystal diamond (SCD) is demonstrated using a 915 MHz reactor. Diamond synthesis was performed using input chemistries of 6-8% of CH4/H-2, microwave input powers of 10-11.5 kW, substrate temperatures of 1100-1200 degrees C, and pressures of 110-135 Torr. The simultaneous synthesis of SCD over 70 diamond seeds yielded good quality SCD with deposition rates of 14-21 mu m/h. Multiple deposition runs totaling 145 h of deposition time added 1.8-2.5 mm of diamond material to each of the 70 seed crystals
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.