Petrel affects compass

[Troglodyver]

I am curious how you did your battery test. Did you just take the battery out, and try it with just the Petrel? That would mean the Petral was off, and maybe the effect was caused by current in the computer. The cheap battery may not have made as much current as the alkaline, or lithium

Buddy and I met at coffee shop today to retest this. We laid the compass flat on the table. Moved the Petrel near it, compass needle moved whether or not Petrel was on. Then we removed the battery and just moved the battery near the compass. Holey moley, the results!

We tried an assortment of AA batteries: alkaline, "heavy duty," and a lithium AA. No current flowing, just the bare battery near the compass. Most deflected the compass needle more than 10 degrees. Some had impact as much as 3" from the compass; others had to be within about an inch.

The AA from Harbor Freight had the least impact. The heavy duty AA from Dollar Tree moved the compass more than that, but less than the other alkaline and lithium AAs.

The batteries had the same type impact on the compass in my Petrel 2.

Once back home, I tried several handheld dive lights to see what effect, if any, they had:

• Light and Motion Sola 1200 was interesting. Depending on which part of the light was near the compass, the needle moved a minimum of 30 degrees. The top of the light near the switch dragged the needle with it; compass was useless.
• BigBlue 1200, moved the needle about 40 - 45 degrees when off; additional 10 - 20 degrees when on.
• Ikelite PC Lite LED impacted the compass least, even though it contains 4 alkaline C cells. The bolt snap on it caused more deviation than the C cells.

Soooo . . . I need to think about how to hold the compass when using a dive light and/or computer. This will usually be a bigger deal (for me) on open water night dives than in caves.

Keep batteries, as well as anything ferrous, away from your compass.

[FW]

...Soooo . . . I need to think about how to hold the compass when using a dive light and/or computer. This will usually be a bigger deal (for me) on open water night dives than in caves.

Keep batteries, as well as anything ferrous, away from your compass.

I use a compass that can be used with only one hand. I keep my computers on the other arm. I survey with a helmet light, and clip off my main light.

[MORGAN]

My father knew a guy who, in a stroke of probably beer-fueled genius, drilled a hole in the stock of his deer rifle and glued a small compass into it, inletting it flush with the wood.

He was proud of his idea and his workmanship, and explained it thus: "Well, you know a compass always points the same way. This way I'll always have a compass and I'll always be able to find my way out of the woods."

He was right; the compass always pointed the same way: toward the barrel of his rifle.

[Kelly Jessop]

My father knew a guy who, in a stroke of probably beer-fueled genius, drilled a hole in the stock of his deer rifle and glued a small compass into it, inletting it flush with the wood.

He was proud of his idea and his workmanship, and explained it thus: "Well, you know a compass always points the same way. This way I'll always have a compass and I'll always be able to find my way out of the woods."

He was right; the compass always pointed the same way: toward the barrel of his rifle.

Was that Red Ryder?................"You'll shoot your eye out"

[MORGAN]

Was that Red Ryder?................"You'll shoot your eye out"

Sounds like a BB gun is all that guy should have been trusted with.


Another guy got a GPS - took it out of the box early in the morning, opening day of deer season, and stuffed it in his hunting coat pocket. Then he picked up his rifle and headed out into the Great North Woods. Later that day, deep in the woods and unsure of where he was, he pulled out his GPS and discovered: "Batteries not included."

My father was a Vermont State game Warden for many years and had a lot of lost hunter stories. No wonder.

[FW]

Sounds like a BB gun is all that guy should have been trusted with.


Another guy got a GPS - took it out of the box early in the morning, opening day of deer season, and stuffed it in his hunting coat pocket. Then he picked up his rifle and headed out into the Great North Woods. Later that day, deep in the woods and unsure of where he was, he pulled out his GPS and discovered: "Batteries not included."

My father was a Vermont State game Warden for many years and had a lot of lost hunter stories. No wonder.

A fat lot of good it would have been even with batteries, if he didn't store a waypoint for his car