By Bernard Williams
Nothing has changed the crappie fishing game like side and down imaging sonar technology.
Several months ago I started hearing about a new type of sonar. I started to do some research and what I found was amazing. You can now distinguish bait fish from game fish and actually see the fish sitting on top of a stump or brush pile. That’s always been a challenge with the older sonar units.
What I discovered is called Compressed High Impact Radar Pulse technology or CHIRP for short. CHIRP has been around for a while. It’s been used by the military since the early 1950’s and declassified around 1960. It’s the first time the technology has been available to recreational and sport fishing at an affordable price.
What is CHIRP?
CHIRP transducers transmit a long pulse across a wide frequency band; traditional transducers operate at 50 kHz and 200 kHz. This limits what targets can be detected and distinguished in the water column. Any object(s) below the boat that are detected in the frequency band, will be seen on the display. CHIRP transducers are designed to operate over a broad range of frequencies (28 kHz – 800 kHz) with no sensitivity loss. You get remarkable target separation and resolution.
CHIRP can be used to distinctly identify targets like individual fish in a school, precise separation between bait fish and game fish, and 5 to 10 times greater detail and resolution. So to sum it up your ability to resolve individual fish, or separate fish from bottom structure, is now a matter of inches, instead of several feet with traditional fishfinders. You’ll see individual fish in groups, instead of a single mass.
Depth finders that use CHIRP
* Garmin echoMap & GPSMap Series
* Lowrance Elite – & HDS Gen2 – with Sonar Hub Networking Module
* Lowrance Gen2 Touch Series
* Humminbird ONIX Series – with SM3000 Black Box
The Lowrance Elite 5 Series starts around $500 and the Garmin echoMap 70dv around $900. The Garmin GPSMap starts around $1,200, HDS Gen2 with SonarHub Sounder Module lists around $1,300 while the Humminbird ONIX Series starts around $1,600.
Is it worth the price?
If fishing time is a factor, then you make the investment.
I tournament fish once a month, usually on weekends. I also fish on large reservoirs and I need to be where the fish are. I made the investment in a HDS Gen2 – with Sonar Hub Sounder Module ($1,700). I chose the Sonar Hub because it includes both CHIRP and Structure Scan. It has made a difference in my catch ratio.
Now I spend a third of my time side-scanning pre-selected areas before I begin fishing. I use my Side-Scan & Down-Scan to find structure and baitfish schools. I mark the structure or baitfish, when completed I turn around and fish the spots I’ve marked with my sonar unit. I usually know when a bite will occur before it happens. If time is important, along with the number of fish in your livewell, investing in an updated CHIRP unit is worth the cost.