A few questions here regarding sonar. I run a Northstar M84 plotter with 1000 watt B260 50khz/200khz transducer.
#1. Transducer Peaking. When "peaking" your transducer, say at 30ft, when do you guys feel the need to "peak" it again? I have been reading a +/- 20% change in depth will require the transducer to be "repeaked". That is only a 6ft change and it seems to me, being we fish in relatively shallow waters, I would need to "peak" the transducer many many times during the course of the day. How often is this really necessary?
#2 Sonar frequency and cone angles. I am having trouble deciding which frequency to run on my sonar. I am told that 200khz is better for the shallow water we fish and is more detailed but my cone angle is only 11 degrees. On the other hand 50khz has a much wider cone angle at 45 degrees but is less detailed and suited more for deep water. My problem is this: If running the 200khz at 11 degree cone angle in 30ft of water, I am only covering 7-8ft of the bottom. If the if the fish are suspended half way up the water column, I would only have a 3.5-4ft coverage area at that 15ft depth. It seems to me that there could be many fish there and I would not see any of them. That bothers me! On the other hand, using the less detailed 50khz frequency in the same 30ft scenario, I would be covering 25-30ft of the bottom. Now the geometry of it.
200khz 11 degree cone in 30ft of water = 8ft diameter circle= about 50 square feet of bottom coverage
50khz 45 degree cone in 30ft of water = 30ft diameter circle = about 700 square feet of bottom coverage
That is nearly 14 times the area of bottom coverage! Am I thinking wrong here for wanting to run 50khz just for the greater coverage yet less detail? What are your opinions?
#3 Sonar Scroll Speed. What do you guys feel is the best speed to scroll your sonar speed? Slow, medium, fast? And why?
