(3) Locations in the continental U.S. should have little trouble with propagation.
In overseas locations, technical literature is not available for defining the expected
propagation nor can guidance be given to cover all cases. This data must be obtained by
c. Oscillator Calibration
. Standard practices
of quartz oscillators,
or (more generally) crystal oscillators, shall include:
(1) Warm up all oscillators for specified period in TB or use a minimum of 24
hours warm-up if period is unspecified.
(2) Set for a minimum frequency difference between the test instrument (TI) and
(3) Oscillators with stability specifications equal to or better than the standard
quartz oscillator shall be calibrated to full specifications using the VLF receiver and
directly by substituting the TI for the standard quartz oscillator. The period for stability
shall be 24 hours minimum.
Maintenance of Records
A frequency logbook
will be maintained by all calibration activities
A frequency logbook is not required for the GPS Time and
Frequency Calibration Workstation, AUTEK Systems
Corporation Model 620.
(1) VLF tracking system users will include, as a minimum, the following
information in the logbook:
(a) Starting date and time of monitored track.
(b) Starting MICROSECONDS setting of VLF tracking receiver.
(c) Current standard oscillator setting.
(d) Ending date and time of monitored track.
(e) Ending MICROSECONDS setting of VLF tracking receiver.
(f) Calculated FFE results.
(g) Resulting standard oscillator setting.
(2) Logbooks for other types of frequency monitoring systems will contain all
pertinent data necessary to verify proper traceability.
(3) Logbook data will be retained for at least 3 years. Upon request, a copy of the
logbook data will be forwarded to USATA.
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