In this article, you will learn the differences between CHIRP and DownScan UnderVision, what each sonar technology is designed for, and when to use each scanning mode to get the best results while fishing.
CHIRP and DownScan UnderVision at a Glance
CHIRP and DownScan UnderVision are complementary sonar technologies designed for different purposes.
CHIRP is optimized for detecting fish, understanding the water column, and quickly scanning large areas. UnderVision (DownScan) provides a highly detailed view of underwater structure, making it easier to identify bottom features and select the best locations for bait placement.
Once UnderVision is installed, you can switch between CHIRP and DownScan in the Fish Deeper app at any time. Please note that only one sonar view can be displayed at a time.
| Carp Fishing Situation | CHIRP | DownScan UnderVision |
| Finding carp in open water | ⭐⭐⭐⭐⭐ Best tool for detecting fish targets in the water column, especially when carp are suspended or moving. | ⭐⭐ Limited. Fish may appear as small dots or faint marks rather than clear targets. |
| Understanding the bottom: mud, gravel, silt | ⭐⭐⭐⭐ Strong for interpreting bottom hardness and composition through sonar returns. | ⭐⭐⭐ Helps visually confirm bottom texture and structure, but is less direct for determining bottom hardness. |
| Depth reading and bathymetric mapping | ⭐⭐⭐⭐⭐ Best choice for accurate depth readings and creating depth maps. CHIRP uses a dedicated narrow depth beam, so the displayed depth value is more precise. | ⭐⭐⭐ Can support general bottom viewing, but CHIRP is recommended when accurate depth readings or bathymetric mapping are the priority. |
| Locating clear spots for bait placement | ⭐⭐⭐ Good for identifying depth changes and bottom transitions. | ⭐⭐⭐⭐⭐ Excellent for spotting clean patches between weed or debris for precise rig placement. |
| Fishing near weedbeds | ⭐⭐⭐ Helps detect fish holding near vegetation, although dense weeds can clutter the sonar view. | ⭐⭐⭐⭐⭐ Clearly shows weed edges, density, and openings in vegetation. |
| Identifying underwater structure | ⭐⭐⭐ Shows structure as strong sonar returns, but with limited detail. | ⭐⭐⭐⭐⭐ Best for identifying branches, timber, rocks, and other underwater features with high detail. |
| Fishing close to drop-offs and ledges | ⭐⭐⭐⭐⭐ Excellent for tracking depth changes and locating fish along slopes. | ⭐⭐⭐⭐ Clearly shows the shape of ledges and bottom contours. |
| Scanning a new fishing area | ⭐⭐⭐⭐⭐ Ideal for the initial scan to locate fish activity, understand depth, and build a reliable depth map. | ⭐⭐⭐⭐ Ideal for a second pass to better understand underwater structure. |
| Bait boat positioning and spot accuracy | ⭐⭐⭐⭐⭐ Excellent for monitoring fish and depth beneath the boat. | ⭐⭐⭐⭐⭐ Excellent for confirming the exact bottom feature where bait and rigs will be placed. |
| Primary role | ⭐⭐⭐⭐⭐ Fish detection, water column scanning, accurate depth reading, and bathymetric mapping. | ⭐⭐⭐⭐⭐ Structure interpretation and precise spot selection. |
When to Use CHIRP
Choose CHIRP when your goal is to:
Search for fish in open water and interpret the approximate size of the fish.
Detect fish suspended in the water column.
Scan a new fishing area quickly.
Monitor depth changes and underwater contours.
Observe fish activity while navigating.
CHIRP is the preferred scanning mode when your primary objective is locating fish and gaining a broad understanding of the underwater environment.
When to Use DownScan
Choose UnderVision when you want to:
Identify underwater structure.
Distinguish vegetation and weed beds.
Locate submerged trees, branches, rocks, or other obstacles.
Better understand bottom contours and terrain.
Find clean spots for precise bait placement.
Confirm exactly where your bait boat is placing rigs and bait.
UnderVision is designed to help you understand exactly what is on or near the bottom, making it easier to interpret underwater structure and select productive fishing spots.
Switching between CHIRP and DownScan
The best results are achieved by switching between CHIRP and DownScan to match your fishing and scanning needs.
A common approach is to:
Use CHIRP to locate fish, identify productive depth zones, and quickly scan the area.
Switch to DownScan to inspect the bottom in greater detail and choose the most suitable location for placing bait and rigs.
Together, CHIRP and DownScan provide a more complete understanding of the underwater environment than either technology alone.