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Guide to Closed Circuit TV (CCTV)

All the bolt on bits of equipment ...
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Bulk Erasers

Not to be considered as a an alternative to ‘Weight Watchers’ as some magic form of weight loss, they are however, a fairly important piece of equipment which hardly ever gets mentioned.

For anyone using an analogue tape based video recording unit, such as VHS or S-VHS, they will probably already be aware that if you place a recorded tape into the machine and press record, the ‘video erase head’ will effectively scrub off the previous recording, before the new one is made.

Although some larger system operators have for a long time now used a desktop mounted ‘Bulk Eraser’ to purge any recordings from the tape, these units are still something of a rarity.

The technical term for the process is ‘de-gaussing’, which means that by passing the cassette over a strong magnetic field, it causes all the tape particles to ‘line up’ and essentially lose any previously stored information (even if the record protect tab is removed!).

Being a relatively fast and simple method for destroying previously made recordings, this technique has now become a recommendation under recently introduced UK legislation, which like many rules and regulations, is effectively quite impossible to enforce.

However, that said, it does make sound sense to clean and condition every videotape before use, albeit that it is time consuming, and the Bulk Erasers themselves, do not come cheap.

As digital recording increasingly makes use of Hard Drives as opposed to removable tape cassettes, these units will inevitably be consigned to the dustbin of history .

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