F75: Iron falsing

[BobBool]

Can the F75's propensity to iron false (nails) be minimized by offsetting the ground balance?

 

[Steve O]

Yes BobBool. Do a GB on clean soil then adjust two or three numbers higher. Check it in the field, then you'll know first hand.

 

[TerraDigger]

Also raise the DD coil 3" above the ground after getting a (good?) signal. DD coils have a propensity to misreport ID numbers/tones on objects within 3" of bottom of coil. Its due to the design of all DD coils, not a Fisher flaw.That is advice from Dave Johnson, lead designer for First Texas Products (Fisher).

 

[WV62]

Just wondering what the 10" elliptical would do to help or hurt the problem?

Ron in WV

 

[NE Digger]

3 or 4 tones tends to exasperate the high tone iron falsing. Happens a lot less with 2F. All running the Gb positive (adding a couple of numbers) will do is dampen the sensitivity of the unit. Wont necessarily make it better on iron ID.
Run 2F, make your swings crisp, and keep an eye on that FE304 meter. Iron is actually pretty easy to get a handle on with the F75 after you get that ear trained.
Even real deep iron has a distinctive sound. A target on the edge of detection may initially make you think its iron, but the grunt will have a little sweet spot in it, and it will be repeatable. Deep iron tends to wander all over the place depending on sweep speed and angle, not to mention it will cause a spike in the Fe 304 meter. Iron will ramp up differently in VCO too as your pinpointing.
Best thing you can do is pay close attention on the targets, and then dig em up to positively ID them. After a while you will be able to call em better. If you walk away from them, you wont really learn much about what the machine is telling you. ALL machines have their own language. you simply have to learn it.

 

[Big Boys Hobbies]

3 or 4 tones tends to exasperate the high tone iron falsing. Happens a lot less with 2F. All running the Gb positive (adding a couple of numbers) will do is dampen the sensitivity of the unit. Wont necessarily make it better on iron ID.
Run 2F, make your swings crisp, and keep an eye on that FE304 meter. Iron is actually pretty easy to get a handle on with the F75 after you get that ear trained.
Even real deep iron has a distinctive sound. A target on the edge of detection may initially make you think its iron, but the grunt will have a little sweet spot in it, and it will be repeatable. Deep iron tends to wander all over the place depending on sweep speed and angle, not to mention it will cause a spike in the Fe 304 meter. Iron will ramp up differently in VCO too as your pinpointing.
Best thing you can do is pay close attention on the targets, and then dig em up to positively ID them. After a while you will be able to call em better. If you walk away from them, you wont really learn much about what the machine is telling you. ALL machines have their own language. you simply have to learn it.

Great post!

 

[daveycross]

This man knows what he,s talking about. I,m in awe.