Jackson Labs PHASE STATION 53100A, User Manual

Page: 52 / 225

PhaseStation 53100A User’s Manual V1.04 25-Apr-2022 52
GPS-disciplined frequency standard and distribution amplifier supplying 10 MHz to
various instruments through long cables.
The 5330A’s reference source was connected with a double-shielded RG400 cable in all
three trials. The
blue trace and magenta traces were taken with the input source
connected with a 3m length of RG58. A significant MDEV peak was visible in the blue
trace… but when the GPSDO was powered down for the
magenta
trace, the spurious
response vanished.
Likewise, as the green trace shows, replacing the RG58 input cable with an equal length
of RG400 also eliminated the interference from the house standard.
As can be seen, the recommendation to use double-shielded cables with these
instruments is not born of excessive caution. Even plots acquired by conventional
frequency and TI counters are vulnerable to crosstalk! With the widespread availability
of GPSDOs and other inexpensive frequency standards, many facilities from
international physics laboratories to ham shacks are equipped with 5- and 10-MHz
distribution networks.
Don’t use low-quality cables with high-performance
instrumentation.