Airmar SS75C-20-M-HB 600W Stainless 20 Degree Tilt Thru-Hull CHIRP Medium Frequency Humminbird 9-Pin

Airmar SS75C-20-M-BL 600W Stainless 20 Degree Tilt Thru-Hull CHIRP Medium Frequency Humminbird 9-Pin

Medium Frequency 80 kHz - 130 kHz

Airmar's new Broadband / CHIRP transducers represent the next generation of technology that will allow fishermen to unlock new secrets in fishfinding. Echosounder operation away from the traditional 50 kHz and 200 kHz has proven that different fish species return better signals at various frequencies. Airmar's Broadband Transducers are capable of operating over a wide (or Broad) frequency band ranging from 25 kHz to 60 kHz and from 130 kHz to 210 kHz.

Traditional fishfinders transmit a pulse at a single-frequency (50 kHz or 200 kHz) which is often referred to as a tone burst. Better deep-water and bottom detection is obtained by transmitting a longer pulse, because the fishfinder is delivering more energy to the transducer. However, the drawback of a long pulse is that it provides reduced target resolution. For example, if a fishfinder transmits a pulse that is 500 microseconds in duration, it has a pulse length of 0.7 m (2.4'). With a tone burst, no targets can be resolved that are closer to one another than the pulse length. So fish less than 0.7 m (2.4') apart, or less than 0.7 m (2.4') from the bottom, can not be detected. Fish schools will appear in this case as a single large mass, while fish close to the bottom will appear attached to the sea bed and will be difficult or impossible to detect.

With CHIRP the transmission pulses are typically very long and may start at 40 kHz and end at 60 kHz. By comparing the shape of the stored transmission pulse with the received echoes from the transducer, it is possible to find echoes in the noise and precisely determine their range with astounding accuracy (see photo). Using CHIRP it is now possible to obtain:

• Much greater range because very long pulses can be used.
• Much better resolution because the sonar pulse is swept across a frequency band (from 40 kHz to 60 kHz, for example).
• Enables targets to be precisely located within inches on the display using pattern matching techniques.
• Closely spaced fish and fish laying on the bottom can be accurately detected and displayed as distinct targets.

Because weak fish and bottom echoes can be resolved within the noise (the snow' on a conventional fishfinder display), it is possible both to detect targets at far greater depths than before and track the bottom at higher boat speeds.

Features:

• Operating frequencies:
• • SS75L-Chirps from 40 kHz to 75 kHz
  • SS75M-Chirps from 80 kHz to 130 kHz
  • SS75H-Chirps from 130 kHz to 210 kHz
• Beamwidth (Adjustable):
  • SS75L-40 degrees to 21 degrees
  • SS75M-24 degrees to 16 degrees
  • SS75H-15 degrees to 9 degrees
• 12 m (40') cable
• Depth and fast-response water-temperature sensor
• Stainless Steel transducer housing
• Boat Size: Up to 8 m (25')
  
• Hull Type: Fiberglass or wood

• Installation Instructions (pdf)