The Dalles adult ladders are now equipped with thin body ferrite tile PIT tag antennas. The goal of these antennas is a detection rate of near 100% and an uptime of near 100%. The first detections at the dam have resulted in each antenna reading each tag 10+ times, which is an indication of a very robust detection system. The antenna systems were operational prior to water up at each ladder with the east ladder watering up on 2/12/2013 and the north ladder watering up on 3/11/2013.
Because the antennas are only two inches thick, the antennas were able to be surface mounted into the counting window slots. Hydraulic disruption within the slots is minimized by constructing the antennas into a “speed bump” design. The thin body design also provides for a dramatically lower cost compared to installing standard body antennas that require extensive concrete remodeling and removal of metallic structure. The ferrite tile that makes the thin body antenna possible also allows it to be installed on metal surfaces.
Ferrite tile is what makes the thin body antennas possible. This technology was first pioneered by Destron Fearing (now Biomark) engineers for use in trench style antennas. The trench style antennas are targeted for embedding in spillways. The PTAGIS Kennewick staff has taken this technology and applied it to flat plate and thin body pass through antennas.
In 2011, the PTAGIS Kennewick staff successfully designed and installed the first ever thin body flat plate antennas. These antennas, built by Biomark fabricators, were installed at Rosa Dam on the Yakima and are in use today. In 2012, PTAGIS Kennewick staff launched the effort to develop the thin body pass through antennas (see October 2012 newsletter). This effort resulted in the 2013 installation of The Dalles antennas which were also fabricated and installed by Biomark.
The future for thin body antennas is bright. Future U.S. Army Corps of Engineers (USACE) projects include antennas for the Little Goose adult ladder, both adult ladders at Lower Monumental and a single antenna at the Ice Harbor adult fish trap. The single antenna at Ice Harbor will provide for a separation-by-code system to target specific fish for trapping and transport. Other possible projects being discussed are both adult ladders at John Day. 
Both of the PIT tag systems at The Dalles (TD1 and TD2 in the database) include fully redundant data collection computer platforms with hourly uploads to the PTAGIS database. The Bonneville Power Administration provided the computers, readers and related electronics. These systems were installed by PTAGIS and are operated and maintained by PTAGIS.
This USACE funded project was supported by an outstanding group of project electricians (Richard Vanhoose and Mike Changar) and biologists (Bob Cordie and Paul Keller) whose positive attitudes and creativity in solving problems made it possible to complete this project on time. The results of these efforts will provide regional fisheries researchers with valuable, low cost, reliable and efficient PIT tag monitoring sites for years to come.
These systems are considered temporary but are being considered as permanent if no disruption to fish passage through the counting window slots is detected.