Fish Finder Questions

[dgax65]

These are the specs for a range of Humminbird products.

Matrix 12 specs:

Display Size:	5.0" diagonal
Display Pixel Matrix:	240V x 240H
Display Type:	FSTN LCD
Display Colors/Grayscale:	12 Level Grayscale
Single Beam
Sonar Coverage	200 kHz / 20° @ -10db
Target Separation:	2.5 inches
Power Output (RMS):	250 Watts (RMS)
Power Output (Peak to Peak):	2000 Watts (Peak-to-Peak)

Humminbird 325

Display Size:	4.0" diagonal
Display Pixel Matrix:	320V x 240H
Display Type:	FSTN LCD
Display Colors/Grayscale:	16 Level Grayscale
DualBeam PLUS
Sonar Coverage	200 kHz / 20° @ -10db 83 kHz / 60° @ -10db
Target Separation:	2.5 inches
Power Output (RMS):	300 Watts (RMS)
Power Output (Peak to Peak):	2400 Watts (Peak-to-Peak)

Humminbird 161 Combo (specs for 160 not listed on website):

Display Pixel Matrix:	320V x 240H
Display Type:	FSTN LCD
Display Colors/Grayscale:	16 Level Grayscale
Single Beam
Sonar Coverage	200 kHz / 20° @ -10db
Target Separation:	2.5 inches
Power Output (RMS):	150 Watts (RMS)
Power Output (Peak to Peak):	1200 Watts (Peak-to-Peak)

PiranhaMax 220

Display Size:	4.0" diagonal
Display Pixel Matrix:	240V x 160H
Display Type:	FSTN LCD
Display Colors/Grayscale:	8 Level Grayscale
Dual Beam
Sonar Coverage	83 kHz / 60° @ -10db 200 kHz / 20° @ -10db
Target Separation:	2.5 inches
Power Output (RMS):	200 Watts (RMS)
Power Output (Peak to Peak):	1600 Watts (Peak-to-Peak

Humminbird 787C

Display Size:	5.0" diagonal
Display Pixel Matrix:	640V x 640H
Display Type:	256 Color TFT
Display Colors/Grayscale:	256 colors
DualBeam PLUS
Sonar Coverage	200 kHz / 20° @ -10db 83 kHz / 60° @ -10db
Sonar Optional:	QuadraBeam PLUS
Target Separation:	2.5 inches
Power Output (RMS):	500 Watts (RMS)
Power Output (Peak to Peak):	4000 Watts (Peak-to-Peak)

One thing to take note of is that the target separation (sonar beam resolution) on all of them is 2.5 inches. The sonar itself can only resolve down to 2.5 inches. The differences lie in the power, number of beams and screen resolution. Power is probably the least of your concerns if you fish in <200 feet of water. As long as you have a good transducer installation, even a low power unit should get enough signal return to see the bottom. Having a dual beam unit gives you greater coverage of the water column and bottom. The higher resolution screen will allow more detail to be displayed. On a 240X240 pixel screen in 120 feet of water, each pixel is going to represent 6 inches of the water column. On a 420 pixel screen, each pixel will only be 3 inches. The higher resolution screen will allow the data that's available to be displayed more clearly and effectively.
In my opinion, you should go with the highest resolution screen that you can afford.