Symmetricom XL-GPS, User Manual

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F51 – GPS Antenna Cable Delay
F51 – GPS Antenna Cable Delay
Use function F51 to display or configure the GPS antenna cable delay. Setting a positive
value for F51 compensates for the time the signal takes to travel the length of the cable from
the GPS antenna to the receiver. The factory setting for F51 is +60 nS (50 feet of RG-59). If
using an optional Down/Up Converter, consult that product’s documentation for directions
on setting the correct cable delay.
F51 Guidelines:
• For RG-59: multiply the cable length by 1.24 ns/ft. to get the value for F51.
• For RG-58: multiply the cable length by 1.4 ns/ft. to get the value for F51.
• Don’t use function F51 to adjust the XL-GPS’s timing outputs ; use F52 Distribution
Cable Delay instead.
See "Factory Default Jumper and Switch Settings for Options" on page 166
Command Line
Use the following format to display the current Antenna Cable Delay setting:
F51<CR>
The XL-GPS responds using the following format:
F51<S><+><DELAY>ns<CR><LF>
where:
F
= ASCII character F (f or F for input string).
51 = the function number.
<S>
= ASCII space character one or more.
<CR>
= carriage return character.
<SEP> = one or more space characters.
<DELAY>
= 1 to 6 digit delay from 0 nS to 999999 nS.
ns = nanoseconds (ns or NS for input string).
<LF>
= line feed character.
Note: Only positive delays are valid.
For example, to see the antenna cable delay, enter:
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