1.32 Echo Stretch

On long ranges target echoes tend to shrink in the bearing direction, making them difficult to see. On short and medium ranges such as 1.5, 3 and 6 nm range scales, the same sized targets get smaller on screen as they approach own ship. These are due to the inherent property of the ra- diation pattern produced by the antenna. To en- hance target video, use the echo stretch feature.

Enlarged in range

direction by ES 2

Enlarged by ES 1

Note 3: Suppress sea clutter and noise before activating echo stretch, since the echo stretch cir- cuit stretches not only target echoes but also sea clutter and noise.

Note 4: Echo stretch 2 is not available with the short pulse.

1.33 Noise Rejection

White noise can be suppressed by turning on N REJ on the ECHO SIG menu.

+

If a target becomes

smaller as it approaches

own ship, use ES 1.

ECHO STRETCH 1 For stretching echoes near own ship

+

If a distant target is hard to see, use ES 2.

ECHO STRETCH 2 Forstretching echoes near perimeter of CRT

1)Press the MENU key.

2)Select the ECHO SIG menu.

3)Press the ENTER/SELECT key.

4)Select N REJ and press the ENTER/SELECT key.

5)Select ON.

6)Press the ENTER/SELECT key.

7)Press the MENU key.

Figure 1-27 Echo stretch

1)Press the MENU key.

2)Select the ECHO SIG menu and press the ENTER/SELECT key.

3)Select STRETCH and press the ENTER/SE- LECT key.

4)Select 1 2, or OFF.

5)Press the ENTER/SELECT key followed by the MENU key.

Note 1: Echo stretch magnifies not only small target pips but also returns from sea surface, rain and radar interference. For this reason, make sure that these types of interference have been suffi- ciently suppressed before activating the echo stretch feature.

Note 2: If the 1.5 nm range is preset for pulselength SP (0.08 μs) or M2 (0.3 μs), and the 3 nm scale for M1 (0.3 μs), the echo stretch fea- ture is not available on these range scales.

1.34 Selecting Pulselength

Pulselength can be selected on the ranges between

0.75and 24 nautical miles, on the menu. Pulselengths available are a short pulse, two me- dium pulses, and a long pulse.

Presetting pulselength

Two sets of pulselengths can be preset on the ECHO SIG menu: P/L SET 1 and P/L SET 2.

1)Press the MENU key.

2)Select the ECHO SIG menu.

3)Press the ENTER/SELECT key.

4)Select P/L SET 1 (or P/L SET 2) and press the ENTER/SELECT key.

5)Select pulselength and press the ENTER/SE- LECT key.

6)Select P/L SET 2 (or P/L SET 1) and press the ENTER/SELECT key.

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Furuno FR-8111, FR-8251 manual Echo Stretch, Noise Rejection, Selecting Pulselength, Presetting pulselength

FR-8251, FR-8111 specifications

Furuno has long been a leader in marine electronics, and its FR-8251 and FR-8111 radar systems continue that tradition. Both are advanced systems designed specifically for professional mariners who demand high performance, reliability, and technological sophistication in their navigational tools.

The Furuno FR-8251 is a powerful radar system that boasts a range of features tailored for commercial vessels. With a 25 kW transmitter, the FR-8251 delivers exceptional performance, providing a clearer and more detailed image of the maritime environment. It is equipped with advanced signal processing technology, including the Doppler processing feature, which allows for the detection of moving targets. This is highly beneficial for collision avoidance, as it provides accurate information regarding the speed and direction of other vessels.

Another noteworthy feature of the FR-8251 is its large, high-resolution display that enhances visibility and ease of use, even in challenging weather conditions. The user interface is straightforward, allowing for quick adjustments and easy navigation through the various settings. It supports a variety of display formats and allows for customization, enabling operators to tailor the information presented according to their specific needs.

On the other hand, the Furuno FR-8111 is equally impressive and designed as a more compact solution without sacrificing performance. This model comes with a 12 kW output and is specifically crafted for smaller vessels, yet it still delivers high-quality radar coverage. Utilizing Furuno’s renowned Automatic Target Tracker (ATT) technology, the FR-8111 enables mariners to efficiently track multiple targets, significantly enhancing situational awareness.

Additionally, both the FR-8251 and FR-8111 come with integrated ARPA (Automatic Radar Plotting Aid), providing users with sophisticated tools for navigation and collision avoidance. The presence of multiple target tracking empowers operators to make informed decisions, optimizing safety at sea.

Furuno’s commitment to reliability and durability is evident in both models, which are designed to withstand the harsh marine environment. Their robust build quality ensures longevity, while their advanced technologies offer peace of mind.

Both the Furuno FR-8251 and FR-8111 are excellent choices for professional mariners seeking cutting-edge radar systems. With their impressive performance, user-friendly interfaces, and advanced technologies, these radar systems set the standard in marine navigation, providing essential support for safe and efficient voyages.