Grayscale depth finders (fishfinder)
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Forum Post Guidelines: This Forum is rated “Family Friendly”. Civil discussions are encouraged and welcomed. Name calling, negative, harassing, or threatening comments will be removed and may result in suspension or IP Ban without notice. Please refer to the Terms of Service and Forum Guidelines post for more information. Thank you
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deepbuzzer
- Petty Officer
- Posts: 98
- Joined: Wed Aug 15, 2007 11:15 am
- Location: Spokane, WA
Grayscale depth finders (fishfinder)
Read a great article by Mark on a color finder and the thermocline,,, now what about a grayscale unit and how does the same info show up on these.
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Marc Martyn
- Rear Admiral Two Stars
- Posts: 4100
- Joined: Sun Apr 08, 2007 1:01 am
RE:Grayscale depth finders (fishfinder)
Well, that is a very good question and I will try to answer it the best I can, not knowing what unit you have, and based on my experiences.
I owned an older Eagle Fish I.D. before I got my current color screen unit. While out on Amber Lake, going down the middle of the lake, I would notice light gray pixels showing up about 15 feet off the bottom. At the time, I thought they were weeds, but also thought that 15' high weeds in a lake like that is unusual. When I got my new color unit, it dawned on me that the gray pixels were not weeds, but the thermocline. I confirmed that by asking Dennis who has a gray scale unit. He told me he was seeing tall weeds off the bottom. I looked at his unit and then mine. The images were at the same depth. What was gray on his screen, was blue on mine.
So, a gray scale does pick up the thermocline, but it shows up like weeds do, but less dense. You can confirm a thermocline by dropping down a Depth-o-therm to the depth just above where the gray pixels start. Take two reading, above the line and below. You should show a significant drop in temperature. Sportsman's Warehouse has the Depth-O-Therm. Make up a unit like I mentioned in the article.
Return images on a screen is based on density. Cold water is denser than warm. The higher end units will now discriminate between cold water and vegetation.
Hope that helps.
I owned an older Eagle Fish I.D. before I got my current color screen unit. While out on Amber Lake, going down the middle of the lake, I would notice light gray pixels showing up about 15 feet off the bottom. At the time, I thought they were weeds, but also thought that 15' high weeds in a lake like that is unusual. When I got my new color unit, it dawned on me that the gray pixels were not weeds, but the thermocline. I confirmed that by asking Dennis who has a gray scale unit. He told me he was seeing tall weeds off the bottom. I looked at his unit and then mine. The images were at the same depth. What was gray on his screen, was blue on mine.
So, a gray scale does pick up the thermocline, but it shows up like weeds do, but less dense. You can confirm a thermocline by dropping down a Depth-o-therm to the depth just above where the gray pixels start. Take two reading, above the line and below. You should show a significant drop in temperature. Sportsman's Warehouse has the Depth-O-Therm. Make up a unit like I mentioned in the article.
Return images on a screen is based on density. Cold water is denser than warm. The higher end units will now discriminate between cold water and vegetation.
Hope that helps.
Last edited by Anonymous on Tue Mar 24, 2009 9:23 pm, edited 1 time in total.