Manual Furuno 1761MK3 (page 10 of 33) (English)

596237

Zoom out

Zoom in

1/33

1-1

1.1 What is Radar?

The term “RADAR” is an acronym meaning

RAdio Detection And Ranging. Although the

basic principles of radar were developed dur-

ing World War II, echoes as an aid to naviga-

tion is not a new development.

1.2 How Ships Determined

Position Before Radar

Before the invention of radar, when running

in fog near a rugged shoreline, ships would

sound a short blast on their whistles, fire a

shot, or strike a bell. The time between the

origination of the sound and the returning of

the echo indicated how far the ship was from

the cliffs or the shore. The direction from

which the echo was heard indicated the rela-

tive bearing of the shore.

1.3 How Radar Determines

Range

Radar determines the distance to the target

by calculating the time difference between the

transmission of a radar signal and the recep-

tion of the reflected echo. It is a known fact

that radar waves travel at a nearly constant

speed of 162,000 nautical miles per second.

Therefore the time required for a transmitted

signal to travel to the target and return as an

echo to the source is a measure of the dis-

tance to the target. Note that the echo makes

a complete round trip, but only half the time

of travel is needed to determine the one-way

distance to the target. This radar automati-

cally takes this into account in making the

range calculation.

1. PRINCIPLE OF OPERATION

1.4 How Radar Determines

Bearing

The bearing to a target found by the radar is

determined by the direction in which the ra-

dar scanner antenna is pointing when it emits

an electronic pulse and then receives a re-

turning echo. Each time the scanner rotates

pulses are transmitted in the full 360 degree

circle, each pulse at a slightly different bear-

ing from the previous one. Therefore, if one

knows the direction in which the signal is sent

out, one knows the direction from which the

echo must return.

1.5 Radar Wave Speed and

Scanner Rotation Speed

Note that the speed of the radar waves out

to the target and back again as echoes is

extremely fast compared to the speed of ro-

tation of the scanner. By the time radar ech-

oes have returned to the scanner, the amount

of scanner rotation after initial transmission

of the radar pulse is extremely small.

1.6 The Radar Display

The range and bearing of a target is displayed

on what is called a Plan Position Indicator

(PPI). This display is essentially a polar dia-

gram, with the transmitting ship’s position at

the center. Images of target echoes are re-

ceived and displayed at their relative bear-

ings, and at their distance from the PPI center.

With a continuous display of the images of

targets, the motion of the transmitting ship is

also displayed.

Report abuse

Libble takes abuse of its services very seriously. We're committed to dealing with such abuse according to the laws in your country of residence. When you submit a report, we'll investigate it and take the appropriate action. We'll get back to you only if we require additional details or have more information to share.

Product:

Forumrules

To achieve meaningful questions, we apply the following rules:

First, read the manual;
Check if your question has been asked previously;
Try to ask your question as clearly as possible;
Did you already try to solve the problem? Please mention this;
Is your problem solved by a visitor then let him/her know in this forum;
To give a response to a question or answer, do not use this form but click on the button 'reply to this question';
Your question will be posted here and emailed to our subscribers. Therefore, avoid filling in personal details.

new questions and answers
new manuals

You will receive an email to register for one or both of the options.

Get your user manual by e-mail

Enter your email address to receive the manual of Furuno 1761MK3 in the language / languages: English as an attachment in your email.

The manual is 0,36 mb in size.

You will receive the manual in your email within minutes. If you have not received an email, then probably have entered the wrong email address or your mailbox is too full. In addition, it may be that your ISP may have a maximum size for emails to receive.

The manual is sent by email. Check your email

If you have not received an email with the manual within fifteen minutes, it may be that you have a entered a wrong email address or that your ISP has set a maximum size to receive email that is smaller than the size of the manual.

The email address you have provided is not correct.

Please check the email address and correct it.

Your question is posted on this page

Would you like to receive an email when new answers and questions are posted? Please enter your email address.

Info

Furuno 1761MK3 Manual

Product: