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parabolic dish

Parabolic Dish Kit For Ultrasound

We now have a 12-inch dish available with twice the gathering power of the 8-inch dish (which is discontinued).

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 parabolic dishe 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 narrow the field of view from 50 to less than 3 degrees. The dish assembly can be used with our r 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 dish pinpoints 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 Kit 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.

Note in the catalog items below that the dishes and receivers are sold separately except when explicity combined in catalog items listed such as "Assembled 12-Inch Parabolic Dish AND Ultra-RX3 Receiver.

12-Inch Parabolic Dish Kit
Qty: Price: $ 129.95

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.

Assembled 12-Inch Parabolic Dish and Ultra-RX3 Receiver
Qty: Price: $ 415.00


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.

ULTRA-RX3 Ultrasound Receiver Kit
Qty: Price: $ 129.95

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.

Assembled 12-Inch Parabolic Dish and Ultra-RX3 Receiver
Qty: Price: $ 415.00


Ultra-RX1 Receiver Kit
This unit covers the 35 to 45 kHz ultrasound band

This kit is hobby level and designed for casual listening. If you are seeking to chase down radio interference due to arcing on power lines then this is not the kit. See the RX-3 which is designed for that.

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.

ULTRA-RX1 Ultrasonic Receiver
Qty: Price: $69.95

ULTRA-RX1 PCB & Manual Only
Qty: Price: $24.95

For links, see the top-left of this page.