Category - Sonar
Lowrance CHIRP -
2014 Oct 12
The ‘buzz’ word in sonar these days is CHIRP (Compressed High Intensity Radiated Pulse) technology. At first I had no interest in it as I am a shallow water (8ft-300ft) inland / coastal angler, and I was under the impression that CHIRP is for 1000ft plus users only.
Then all of a sudden people started talking about ‘CHIRP Lite’, which is essentially the name given to a low power affordable shallow water fishfinder. The unit that made me reach for my wallet was the launch of the Lowrance Elite-7 CHIRP. I had a pretty realistic expectation of the unit as the release video by Lowrance was not that impressive, but I am a ‘sonar addict’ so I had to try it for myself.
My first time out did not impress me at all as I could see no improvement whatsoever over the standard 200/83kHz while trolling (3mph). Then I found a brushpile with fish on it and sat above it while dropshotting to it. The Medium CHIRP gave a much cleaner water column without having to turn the sensitivity down. This meant that I could track my lure and the fish a lot better than traditional 200/83kHz. This statement has previously earned me comments such as “this is an inexperienced CHIRP user”, which I cannot deny, but those were my honest findings and I still stick by my statement months later.
After several months of using the Elite-7 CHIRP and continually tweaking the settings, I still could not get a better result and could not understand why. Then one day while playing with the unit on simulation using a few recordings I took previously I found something very strange … a major loss in history resolution as one changes from 200kHz / 83kHz / High CHIRP / Medium CHIRP.
So I went out and logged an area using the four frequencies over a course of the exact distance in meters. Take note that I was idling along the exact course at the exact same speed for all four passes. The most shocking is how slow the Medium CHIRP scrolls when compared to the 200kHz, and the result – nearly 50% loss in history resolution. (p/m = pixels per meter)
Lowrance Point1 - A Must Have!
2014 Oct 06
The Point-1 GPS Receiver / Compass / Heading Sensor in my opinion, is one of the top three products Lowrance has launched in the past few years. The reason I say this is that it has done two major things –
1. Stabilized the charts when approaching a waypoint at very slow speeds
2. Stabilized the charts when fishing single, or multiple waypoints from a stationary position.
The keywords here are “slow speeds and stationary”, as any experienced user will tell you, have always been a bit of a problem with chart plotters. The reason for this is the lack of a directional gyro, or heading sensor / compass as it is more commonly known.
CoG (Course over Ground) on a chart plotter without a heading sensor is created by a presumed course taking your trail history as a guideline. Under Chart Options you can select Heading Extension, Course Extension or Both. If you select either Heading or Course Extension without having a heading sensor, you will notice two main things when driving at the console on the main motor:-
1. When you turn to port, your extension line will first go to starboard before catching up, and it is this phenomenon that makes it so difficult idle to a waypoint accurately. This is made even worse if you have a receiver mounted directly above your transducer (where it should be). The reason for this is that a boat turns very much like a forklift, as it is being steered by the back, and not the front like on a car or when using the trolling motor.
2. You will also notice that if you hit reverse, your pointer will tell you that you have turned the boat around 180°, when in fact it is still pointing in the same direction, just going backwards.
Lowrance HDS8m Gen2 - Still the Perfect Chart Plotter