Parabolic Dish Kits For Ultrasound
We now have a 12-inch dish available with twice the gathering power of the 8-inch dish.
In some ultrasound applications, it is useful to narrow the field of view of the sensor, which alone has a typical beam width of 50 to 60 degrees. Very narrow beam widths are desirable when trying to locate targets at a distance, such as sparking equipment on AC power distribution systems or one of a number of biological sources. For objects that are close at hand, using the sensor alone is preferred.
Our clear plastic 12-in diameter 8-inch focal length and 8-inch diameter 6-inch focal length parabolic dishes are designed to work with a 400SR16 or similar piezo transducer (PZT). They achieve pressure gains over the sensor alone at 40 kHz of 27 to 28 dB and 18 to 22 dB respectively and narrow the field of view from 50 to less than 3 degrees. The dish assembly can be used with our popular Ultra-RX1 or Ultra-RX3 ultrasound receivers (shown with the dish assembly but sold separately). A weak spark (generated by 400 volts or more on a AC power distribution line) or bat transmissions will produce pressure waves with an RMS pressure of roughly 0.5 to 5.0 Pa (75 micro-psi) at ten feet. The dishes pinpoint the source location and the added receiver provides for recording or headphone reception.
See the articles page for audio recordings of a received weak spark and insect transmissions.
The Parabolic Dish Kits includes the dish, piezo sensor, sensor PCB, 3 struts, instrumentation bracket, pistol grip, and hardware. The kit manual includes assembly instructions, mounting techniques for the Ultra-RX1 or Ultra-RX3, a discussion on parabolic dish gain, and references. Assembly time is about one hour, requiring pliers, screw drivers, and soldering iron.
If kit building is not your thing, we'll assemble and combine together a dish and Ultra-RX3 for you. Allow a week or two for shipment.
Ultra-RX3 Receiver Kit
This unit covers the 35 to 45 kHz ultrasound band.
The RX3 ultrasound receiver kit replaces the RX2. It features lower-noise, higher gain, and center-frequency adjustment for the detection of weak coherent and/or noise-based signals in the 32 to 42 kHz range.
These changes - to accommodate location of RF noise due to lower level power line sparking - were substantial requiring a completely new PCB.
Stand alone, the unit is ideal for listening to bats and insects, detecting air leaks, or finding other ultrasound sources. Combined with our 12-inch parabolic dish (sold separately) it is useful for pinpointing signals at 20 to 50 feet and includes an adjustable center frequency for focusing on frequency-specific targets.
The Kit is shown in the picture. The PCB (5.68 by 3.16 inches) fits snugly in its clam-shell case (L 6.16 W 3.677 H 1.378 inches), along with two 9V batteries and a 400SR016 piezo transducer (PZT). The circuitry expands on that of the RX1 and Rx2, featuring a low-noise, high-gain 40 kHz amplifer, a 602-style mixer, two-stage low-pass filter, and audio preamplifier. Two outputs are provided, a mono-output of the preamplifier signal and a boosted output for 8 - 24 ohm headphones or a small speaker. Kit time for the experienced builder is less than two hours. Through-hole parts are used throughout. The 9-volt batteries and parabolic dish are not included.
The signal pressure levels of natural and man-made ultrasound emissions can vary widely. transmissions by bats can be strong at close range but will be weak at a hundred feet. Pressure signals caused by sparking on AC power distribution systems are generally weaker and copy must be assisted by the addition of a gain antenna, such as our parabolic dish pictured above. A typical weak spark, generated at 400 volts on an AC power distribution system, may produce a weak RMS pressure of 0.5 Pa to 2 Pa (75 micro-psi) at ten feet.
If kit building is not your thing, we'll assemble and combine together a 12-inch dish and Ultra-RX3 for you. Allow a week or two for shipment.
Ultra-RX1 Receiver Kit
This unit covers the 35 to 45 kHz ultrasound band
You can DX the alien nations – insects, rodents, bats, and more – in the 35 to 45 kHz ultrasound band, listening to their feeding, communication, and navigational signals. You can explore man-made ultrasound signals; you'll find them all over your house. Ultrasound, in general, refers to all sound waves above the range of human hearing, about 20 kHz.
Listen to this windows media file of bugs and beetles chatting in my lawn in October in Kansas, recorded with the Ultra-RX1.
Our ULTRA-RX1 receiver kit tunes the most active part of the band, 35 to 45 kHz, with a 10 kHz wide audio bandwidth. Signals emitted across species vary from single sine waves to chatter with a rich mix of harmonics and pulses. Sound pressure levels (SPL) emitted range from roughly 70 to 110 dB, sufficient to be heard from 25 to 100 feet with a high gain receiver, such as our RX1. Signals heard generally are a pattern of “clicks.”
As pictured, the PCB (2.65 by 2.95 inches) and parts fit in our plastic clam-shell case (L 4.38 W 2.95 H 1.0 inches), along with a 9V battery (not included). A 40 kHz piezo transducer (PZT) is mounted on the front panel, and the power switch, frequency tuning pot, audio amp volume pot, and 3.5mm stereo jack, are accessible from the back panel. The stereo jack accepts 8-ohm, 24-ohm, or 2K headphones with a 3.5mm stereo plug. Our kit philosophy is to “build a little, test a little.” In each assembly section of the manual, step-by-step instructions are followed by test instructions, thereby confirming operation before proceeding. A 9V battery and VOM cover a majority and sufficient number of the measurements for success. To radio hobbyists, assembly, test, and use of this kit will feel like building a direct conversion radio receiver.
Build time for the experienced kitter is about 2 hours. Even though the construction is through-hole, a small iron, good lighting and good vision are necessary given that the parts are closely spaced. The manual is 18 pages and includes a comprehensive schematic, enlarged picture of the PCB, and brief explanation of each section of the receiver.
40 kHz Ultrasonic CW Practice Transceiver Kit
Can also be used as an ultrasound test transmitter or as a traditional frequency-division bat/insect detector.
The primary purpose of the Ultra-QP is to assist you and others in improving your Morse code and CW message exchange techniques. You can use several QPs in a group to exchange code or one QP yourself with an earpiece (provided) or headphones as a code practice oscillator, listening to the transmit sidetone. Non-participants cannot hear the ultrasound transmitted.
Listen to this CW file to hear CW sent from one Ultra-QP to another over 20 feet.
Imagine attending a CW Ultrasonic QSO Party in a gym. In round robin fashion, each participant receives and in turn sends to the group, thus practicing CW communications. Then imagine exploring and learning about the architecture and operation of this unique ultrasound frequency-division receiver and transmitter. No RF equipment or license required!
The receiver amplifies the output of a pressure-to-voltage 40 kHz piezo transducer by over 20,000! A PIC micro-controller then converts the analog signal to digital and divides it down to 700 Hz. The PIC then supplies a constant level of audio via an RC and volume control network. During transmit, the PIC develops a 40 kHz square wave which is used to drive a TX transducer via a PNP-NPN transistor pair. Near-full breakin , QSK, and a side tone are also supported by the PIC.
As pictured, the PCB (2.950 by 2.650 inches) and parts fit in our plastic clam-shell case (4.38 by 2.95 by 1.0 inches), along with a 9V battery (not included). Transmit and receive piezo transducers mount on the front panel. The back panel features: power switch with LED, key jack, audio stereo jack, and volume control. The audio jack accepts a crystal earphone (included), hi-z phones or 8-ohm stereo headphones (phones not included). Our kit philosophy is to “build a little, test a little.” In each assembly section, step-by-step instructions are followed by test instructions. A 9V battery and VOM cover a majority and sufficient number of the measurements for success. Assembly time for the average kit builder is about 1 hour. For more information on the Ultra-QP, a describtion of the circuit and kit may be viewed at www.midnightscience/article-u3.html
Ultra-TR40 Transceiver Kit
Our Ultra-TR40 Transceiver Kit (called the Ultra-Mite in the last newsletter) tunes an active part of the band, 35 to 45 kHz, with a 10 kHz wide audio bandwidth and transmits (CW) at 40 kHz. You can listen to bats, insects, beetles, rodents, earth sounds, and man-made sounds.
Sound pressure levels (SPL) emitted by bats and insects range from roughly 70 to 110 dB at one foot, sufficient to be heard from 25 to 100 feet. Input power to the transmitter is adjustable up to 2 mWatts, thus emitting a comparable SPL signal level.
As pictured, the PCB (5.68 by 6.16 inches) and parts fit in our plastic clam-shell case (L 6.16 W 6.67 H 1.74 inches), along with a 9V battery (not included). Transmit and receive piezo transducers (PZTs) mount on the front panel. The back panel features: receive frequency tuning knob, power switch with LED, TX key jack, audio stereo jack, and volume control. The audio jack accepts a 3.5 mm stereo jack or a 3.5 mono jack (jumper select on the PCB).
Our kit philosophy is to “build a little, test a little.” In each assembly section of the manual, step-by-step instructions are followed by test instructions, thereby confirming operation before proceeding. A 9V battery and VOM cover a majority and sufficient number of the measurements for success. To radio hobbyists, assembly, test, and use of this kit will feel like building a
QRP radio transceiver. Build time for the experienced kitter is about 2.5 hours. Even though the construction is through-hole, a small iron, good lighting and good vision are necessary given that the parts are moderately spaced. The manual is 20 pages and includes a comprehensive schematic, enlarged picture of the PCB, and brief explanation of each section of the unit.
Ultra-Test Gen1 Kit
With this kit and an existing electronic function generator, you can create a simple ultrasound signal generator for the bench with a reasonably flat (~constant) pressure output for the 35 to 45 kHz band of frequencies. The kit includes a 400ST16-ROX transducer, or TX PZT. The frequency from the function generator is also the frequency of the pressure wave generated. For other frequency bands of interest, simply substituting another TX PZT should suffice, from about 20 through 80 kHz. The 400ST16-ROX puts out about 17 Pa, pressure at 1 foot, for a 10 V RMS input from the function generator. In addition to the PZT, this kit includes a case - same as used in the Ultra-RX1 noted above - and discrete parts including a 10 MHz GBP op-amp used to configure a synthetic inductor for broad-band tuning. You'll supply the vector board, which needs to be 2950 by 2650 mils to fit in the case.
For more detail, browse the following articles on the ultrsonic-articles page: "A PZT Signal Generator for the Bench," and "A PZT Receiver Jig for the Bench," which is offered as a kit below.
Ultra-RX Test Jig1 Kit
This bench receiver kit is designed to work in concert with the TEST GEN1 kit listed above for the 35 to 45 kHz ultrasonic band. It consists of a synthetic inductor for broad-band tuning of the RX PZT and a op-amp amplifier with gain, added to ease scope measurements. Again, since PZTs are inherently narrow-banded, you'll want to select another PZT if working outside this band of frequencies. The kit includes a 400SR16-ROX PZT, and two 10 MHZ GBP op-amps to provide frequency tuning and gain. The PZT is tuned by adjusting the value of the synthetic inductor, where the inductance is equal to ~ the product of the values to two resistors and one capacitor. In addition to the PZT and op-amps, this kit includes a case - same as used in the Ultra-RX1 noted above - and discrete parts. You'll supply the vector board, which needs to be 2950 by 2650 mils to fit in the case.
For more detail, browse the following articles on the ultrasonic-articles page: "A PZT Receiver Jig for the Bench," and "Transmitting Ultrasound with a 40 kHz PZT."
For links, see the top-left of this page.