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difference between downvu and chirp?

Old 03-28-2014, 07:40 AM
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Default difference between downvu and chirp?

hey whats up everyone. just wanted to know if there was any major difference between these 2. advantages of one vs the other? drawbacks of either?
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Old 03-28-2014, 08:09 AM
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I wouldn't say that there are disadvantages to either unit, just things that you may use more one for than the other. The major differences between the two is that Chirp is beefed up and upgraded sonar, whereas downvu is used more to defining structure underneath you, much like sidevu it's used more as a helpful tool that a sole means of finding structure or fish.

Chirp also has the ability to go ALOT deeper than downvu. To get a good return with downvu or any down or side imaging unit, you will need to be going somewhat slow to get the best picture. Normally between 1-4mph, while chirp can be used at speed or when trolling.

I'm sure people who have both can chime in and give you a better description, but those are just the things that stick out in my mind.

Keith
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Old 03-28-2014, 09:57 AM
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Originally Posted by ofl0926 View Post
hey whats up everyone. just wanted to know if there was any major difference between these 2. advantages of one vs the other? drawbacks of either?
A good question as there is some terminology that at time seems to confuse us.

CHIRP at first only was refereed to as a fishing finding technology...but now it also is incorporated into the down and side scan.

1)Traditional sonar is often referred to as "tone burst..or single burst sonar as it fires one single pulse at the selected frequency.
Example: one pulse at 200 kHz.

2) CHIRP (Compressed-high-intensity-pulsed-radar) also called Swept frequency....and sometimes called Broadband CHIRP.
This technology has been on the market for several years and is generally accepted as the future of recreational sonar as it has many advantages.

A CHIRP system fires a band of pulses that sweep from one end of the selected band to the other....many pulses each at a different frequency and ranging thru varying cone angles .
Example: On a B75H ...Sweeping form 130 kHz thru 210 kHz and with a cone angle of 15 to 9 degrees.

Recreational sonars come in many variations..they can look only for fish, or they can look for hard targets such as bottom and structure..or they can do both.

Hard target capability can be either down scan or side scan ...or even better..both down and side at the same time.
Designed specifically for hard target detail.. this system is normally limited to a slower boat speed and shallow depths..depth down to an average of 150' to 200' is considered most common.

Now it gets a bit more interesting...

Downscan/Side scan now comes in with either traditional sonar technology or now with CHIRP technology.

For Example:
A Garmin echoMAp70dv comes with an All-in-one HD-ID and DownVu transducer...this uses traditional technology for both the fish finding sonar and the down view.(Downscan)
But..if you add the GCV 10 black box.... the DownVu/SideVu is now uses CHIRP technology for its down and side scan to achieve greater overall targeting capacity.

The same with Raymarine, Simrad, Lowrance and Hummingbird..they are using various levels of CHIRP technology in their fish finding sonar and down and side scan units.

So you can use a CHIRP (or traditional sonar ) system to find the fish...and use a traditional (or CHIRP) down/side scan to determine hard target information at the same time..with the same machine...and show the results of both on a screen.













Last edited by semperfifishing; 03-28-2014 at 10:29 AM.
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Old 03-28-2014, 10:53 AM
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those pics really make me understand both downvu and chirp. thanks everyone
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