DEGAUSSING FACTS
To erase recorded
data, it is necessary for the strength of the degaussing field to be
significantly greater in value than the coercivity of the magnetic media.
Data is typically
not lost until its level has been decreased around 60%
below its original signal level, dependent upon
the drive system.
A complete erasure level, for most users, is
considered to be 60 dB below the original signal level – this of
course depends on user requirements. A 60 dB signal decrease equates
to reducing the signal to one tenth of one percent of its original
value.
By using AC current
the degausser creates an alternating magnetic field of sufficient
intensity to saturate the media and then by slowly withdrawing or
reducing the field, the magnetic media is left in a magnetically
neutral state.
Magnetic media
products that have factory prerecorded magnetic servo patterns
should not be degaussed. Degaussing would erase the factory written
magnetic servo signals and leave the media unusable. For all other
magnetic media (without magnetic servo signals), after proper
degaussing, the quality of subsequent data recording should be
unchanged or even improved.
| MAGNETIC TAPE
PRODUCTS |
TYPICAL COERCIVITY |
COMMENTS |
| 9-Track Reel-To-Reel Computer Tape |
300 Oe |
|
| TK50, TK70 |
350 Oe |
|
| 3480, 3490 OE |
520 Oe |
|
| SLR1, SLR2, TR-1, DC2120, DC6150 |
550 Oe |
|
| SLR3, SLR4, SLR5, TR-3, DC9100 |
900 Oe |
|
| SLR24, SLR32, TR-4, ADR30, ADR50 |
900 Oe |
Caution: Degaussing will render Media un-usable! See Note
1 |
| TR-5, SLR40, SLR50, SLR60, SLR100 |
1650 Oe |
Caution: Degaussing will render Media un-usable! See Note
1 |
| DLT tape III, DLT tape IIIXT |
1540 Oe |
|
DLT tape IV
|
1850 Oe |
|
| SuperDLT tape |
1900 Oe |
|
| D8: 8mm 112m, 8mm 160m |
1600 Oe |
|
| DDS1: 4mm 60m, 4mm 90m |
1590 Oe |
|
| DDS2 4mm 120m |
1750 Oe |
|
| DDS3 4mm 125m |
2250 Oe |
|
| DDS4 4mm 150m |
2350 Oe |
|
| DD-2 19mm |
1550 Oe |
|
| DD-2QD (Quad Density) 19mm |
1850 Oe |
|
| DTF-1 |
1579 Oe |
|
| DTF-2 |
2300 Oe |
|
| Redwood SD-3 |
1515 Oe |
|
| Magstar MP: 3570-B, 3570-C, 3570-C/XL |
1625 Oe |
Caution: Degaussing will render Media un-usable! See Note
1 |
| Magstar: 3590, 3590-E |
1600 Oe |
Caution: Degaussing will render Media un-usable! See Note
1 |
| STK-9840, STK-T9940 |
1625 Oe |
Caution: Degaussing will render Media un-usable! See Note
1 |
| LTO-Ultrium1 |
1850 Oe |
Caution: Degaussing will render Media un-usable! See Note
1 |
| Mammoth 8mm, AIT-1 8mm, VXA-1 8mm |
1320 Oe |
|
| AIT-2 8mm |
1380 Oe |
|
| M2 Mammoth2 8mm |
1350 Oe |
|
| 3.5" 720KB DD Microdisk |
650 Oe |
|
| 3.5" 1.44MB HD Microdisk |
720 Oe |
|
| 5¼ 360 KB DD Minidisk |
300 Oe |
|
| 5¼ 1.2Mb HD Minidisk |
650 Oe |
|
| VHS Standard & Betacam |
700 Oe |
|
| SVHS |
850 Oe |
|
| M II Betacam SP/Digital Betacam |
1500 Oe |
|
| U-matic Video |
750 Oe |
|
| Zip 100 MB Disk |
1550 Oe |
Caution: Degaussing will render Media un-usable! See Note
1 |
| Zip 250 MB Disk |
2250 Oe |
Caution: Degaussing will render Media un-usable! See Note
1 |
| SuperDisk 120MB |
1500 Oe |
|
| NOTE 1 |
|
These products have factory
prerecorded magnetic servo tracks. The media will be unusable,
if the servo tracks are bulk erased (degaussed). Products that
use factory prerecorded magnetic servo signals should not be
degaussed unless destruction of the recording media is
desired. | Return to Top
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|