This unique bat detector kit is available, from Tony Messina in the US. The same Gentleman who brought us The Simple Bat Detector (frequency division kit). This heterodyne bat detector is the result of a joint effort of both Tony Messina (in the USA) & Frank Pliquett (in Germany).
This heterodyne-based Bat Detector is unique because it has the ability to actively scan ultrasonic frequencies for bats. Hence, the name: The Bat Scanner.
The Bat scanner is currently available as an almost completed kit, where all of the delicate soldering and assembly has already been done for you (and checked \ tested), by Tony. The kit is supplied with everything you need to complete the construction. All that is required are basic soldering skills and the proper tools to create the needed holes and openings in the plastic case provided. Video and photos of the prototype can be seen here: The Bat Scanner's beginnings - Prototype phase
Some of the photos show the detector built with a round display, this may be available by request; but the kit is currently supplied with a rectangular display window.
Step-by-step assembly instructions, with color pictures are provided with the kit. I found the assembly straight-forward and very fun! I was one of the first hobbyists to receive one of these units.
The very first, original units had a buzz/hum caused by the multiplexing of the 2 digit LED display. In any case, this noise was very low ... often lost in the hiss of the amplifier - and definitely overcome by the bat calls. This issue has been addressed, and the current version of this kit no longer produces this low hum/buzz. Several other modifications and enhancements have been made, to further improve the detector's performance.
As per Tony Messina: "...about the firmware changes ... we have made some changes to the way the buttons are handled. The debounce times have been extended, so the buttons switch cleaner. We have also made a change that keeps the frequency from jumping if you press a button to stop the scan or bring up the blanked display from power save. We also added a Scan Hold ( SH ) mode, similar to the Scan Pause ( SP ) mode, but with a very much longer delay. "
Therefore, as of this writing, anyone ordering the kit will be receiving the new, enhanced version. I like this bat detector very much! During operation, it scans very quickly through it's frequency range (10 to 80kHz, in 2kHz increments) and will stop and display the frequency of whichever bat happens to fly within range!
The buttons also allow the unit to be used as a conventional Heterodyne bat detector as well, where the desired frequency can be selected and monitored. I use it this manner from time to time myself. Although, to some, it may not seem as fun as watching the unit scan the airspace above your garden. When used in this manner, the unit goes into a Power Saving mode, where the LED display powers off, while it waits and "listens" for any signals. At which point, it will blink in sync with the signals received (while also being heard through the speaker).
Here is the main link to the Bat Scanner, where a lot of information and details can be found. The site also contains links to the Construction Manual and User Guide:
Tony Messina's Bat Scanner
I have used this detector very extensively, since completing the assembly. I've found it's sensitivity to be equal to many of the other bat detectors I own, including commercial units costing twice as much. The compact speaker provides nice sounding audio and the unit is a lot of fun to use. And of course, this detector is very useful in the field when encountering flights of more than one species of bat at a time. You can come close to IDing the bats right in the field, just by glancing at the display - without having to do any tuning.
In conclusion, if you enjoy enjoy building bat detector kits, then I would recommend this kit very highly. It is also proves to be a great platform for experimenting.The current price of this kit, for US buyers, is around $100 which includes shipping. Price is subject to change slightly; so Bat enthusiasts should always e-mail Tony or Frank, regarding availability, and for current price and shipping costs, etc.
Tony Messina (USA) - Tony Messina's Page
E-mail: Tony Messina
Frank Pliquett (Germany) - Frank Pliquett's Page