68 Chapter 4
Making SRL Measurements
How to Make SRL Measurements
Measurements") Be sure to determine the quality of the connector being used; some
cable connectors degrade rapidly with use. The response of a bad connector is often
large enough to swamp out the response from cable SRL.
Connector L and C Values
Table 4-2 shows some typical values for two types of slip-on connectors for
mainline cable:
Table 4-2 Typical L and C Values
For the connectors in Table 4-2, use of values within these ranges should be
optimum for the best corrected connector fault response and lowest SRL spikes.
Values far outside this range usually indicate a bad calibration, a poor connector or
connection, or a close-in cable fault which cannot be compensated by the connector
model.
NOTE The optimum calculated value for the connector lengths of “Gilbert Pogo”
connectors may be slightly negative. This is a normal value and should not be a
cause for concern.
For type-F connectors, which are typically used to measure 75 ohm drop cable, the
range of connector L and C values will vary widely and will depend greatly on the
quality of the type-F connector.
Connector L Value C Value
GTC-700-TX-GHZ-N (“GHz”) 40 to 80 mm 0 to 0.15 pF
GTC-700-TX-N (“Pogo”) -12 to 12 mm 0 to 0.125 pF
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