Judicious selection and maintenance of tape and tape transports minimizes dropouts

Van, K. W.

English

NASA Technical Reports Server

June 1971	 Brief 71-10160 
NASA TECH BRIEF 
NASA Pasadena Office	
_4V 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a aubscription basis from the National Technical Information 
Service, Springfield; Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Off i ce, NASA, Code KT, Washington, D.. 20546. 
Dropouts in Magnetic Tape Recording and Reproduction 
A monograph on an examination of dropouts that 
occur in magnetic recording and reproduction proces-
ses discusses the causes of dropouts and means of 
minimizing them. 
Dropouts occur when the tape lifts away from the 
surface of the head because of tape nodules or debris 
buildup, or when the tape drops away because of 
tape deformation or holes in the coating. 
Dropouts can be caused by a number of factors. 
Except in those rare cases where tape handling 
equipment degrades the tape, responsibility for drop-
outs lies with the tape itself. This is particularly 
true for the oxide particles; but the backing, es-
pecially polyester, is also suspect since it is tacky 
and susceptible to static charge buildup. Finally, in 
repeated operation, an accumulation of contamination 
in the tape transport, or of debris on the head or 
guiding surfaces, often transfers to the tape and 
causes dropouts. 
Although the traditional dropout formulas are ex-
cellent for their intended purpose, they are not 
suited for small dropouts having an area of in-
fluence less than a track width. The formula that 
should be used is developed and stated in the mono-
graph, along with comparisons between its results 
and those of the traditional techniques. These results 
show that dropout characteristics, at least for small 
dropouts, are not as severe as originally thought. 
Dropouts of large proportion, i.e., those which 
extend across a track width or more, can be easily 
spotted using several tape inspection machines. In 
most instances, these machines also clean the tape. 
Gross faults are usually due to improper reeling 
or damage within the tape transport system. 
Dropouts can be minimized by judicious selection
and maintenance of tape and tape. transports. If 
the tape becomes contaminated, but the general tape 
quality has not been destroyed, it can be restored 
to the original characteristics by proper cleaning. 
(Certification to ensure the validity of the cleaning 
process is recommended.) 
The precautions to be observed in minimizing tape 
dropouts are self-explanatory. In general, they involve 
extreme care in cleanliness and handling, commen-
surate with the criticality of the requirements of the 
individual user. A conscientious, well-trained operator 
substantially ensures maximum performance from a 
high quality tape and transport system. Where the 
incidence of dropouts is inordinately high, it is ad-
visable to examine all factors that might contribute 
to the problem, including the tape. This applies 
to the total environment of the tape before and after 
recording. 
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
NASA Pasadena Office 
4800 Oak Grove Drive 
Pasadena, California 91103 
Reference: TSP71-10160 
Patent status: 
No patent action is contemplated by NASA. 
Source: W. Van Keuren of 
Caltech /J P L

under contract to
NASA Pasadena Office
(N PO- l 1519)

Category 03 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
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Dropouts in magnetic tape recording and reproduction

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