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Louis,

I measured about 1 G very close to the motor in my American Harvest 
dehydrator and about 400 mG where I usually bake tapes (near the top of 
the stack).

No one has ever complained about the American Harvest FD60 erasing 
tapes. Mine is the model with the motor on the bottom, the newer ones 
have a motor in the lid.

To put this in perspective, my tape demagnetizer read 2 G at about one 
foot. 2 G is the limit of resolution of my tri-axis magnetic field meter 
which was in ELF mode and all three axes were measured.

On the other hand, my studio was reading around 1 mG, more when I moved 
rapidly (because I was cutting the 0.5 G earth's field).

The canonical paper on this (maybe the only paper) is Jay McKnights at:
http://home.comcast.net/~mrltapes/field-strength-for-partial-erasure.pdf

This might be useful for converting among the differing field units:
http://www-d0.fnal.gov/hardware/cal/lvps_info/engineering/mag_conv.htm

Cheers,

Richard



On 2013-10-29 12:51 PM, Louis Hone wrote:
> It's been a while since I've baked tapes in the oven. I'm about to embark
> on a project that involves baking half a dozen Ampex 456 quarter inch tape
> on 10.5 inch reels. We have a new kitchen oven that has a dehydrate setting
> (130 degrees F) so it seems perfect for the job. However, I notice that my
> Trifield Meter indicates that the magnetic field is way over 100
> milliGauss. My old oven in which I baked many tapes, probably had the same
> reading but I never measured it. I'm not too thrilled subjecting a master
> tape to such a strong field. Has anyone else ever measured the magnetic
> field of their kitchen or tape baking oven/dehydrator ?
>
> Louis Hone
>
-- Richard L. Hess                   email: [log in to unmask] 
Aurora, Ontario, Canada                             647 479 2800 
http://www.richardhess.com/tape/contact.htm Quality tape transfers -- 
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