3
Mounting Instructions
The mounting point on the structure should be
faced to a diameter of 1.25 inches. For
measurements involving frequencies above 1 kHz,
the surface should be flat within 1 mil and have a
surface texture no greater than 32 micro-inches.
The tapped hole must be perpendicular to the
mounting surface and at least two threads deeper
than the stud. This will prevent a gap between the
transmitter and the mounting surface producing
optimum frequency response.
Proper screw torque on the mounting stud is also
required. Under-torquing the transmitter reduces
the stiffness of the coupling. Over-torquing can
cause permanent thread damage to the transmitter.
It is recommended that the 1/4-28 stud be torqued
to a value of 30 inch-pounds.
SURFACE 32 1.25
″
DIA MIN
FINISH
.004 A
.001
-A-
.35
.25
Before stud mounting the transmitter, a coupling
fluid should be applied to the mating surfaces.
The coupling fluid protects the mounting surface
and optimizes the frequency response by
increasing the coupling stiffness. Suggested
coupling fluids are machine oil or vacuum grease.
It is recommended that a thread adhesive such as
Loctite 222 be used.
Cable Routing and Electromagnetic
Interference
Walkie-talkies, power lines, or even electrical
sparks may cause signal interference. The
following guidelines will eliminate many
measurement errors due to electromagnetic
radiation and electrostatic discharge (ESD).
Assure that high quality, well shielded cables are
used. If cable splices are made, complete
shielding must be maintained.
Proper cable routing is imperative. Never run
transmitter cable alongside AC power lines; cables
must cross AC power lines at right angles. Where
possible, provide a separate grounded conduit to
enclose the transmitter cable. In addition, route
the cable away from radio transmission
equipment, motors/generators, and transformers.
Finally, avoid routing the cable through areas
prone to ESD. Even though transmitters are
protected against ESD failure, temporary
distortion signals may appear at the output.
Cable Grounding and Ground Loops
In order to provide proper shielding and prevent
ground loops, cable grounding should be
carefully considered.
For transmitters using
two conductor shielded
cable
, the power is carried on one lead and the
return on the other. The cable shield serves to
protect the signal from ESD and electromagnetic
interference (EMI). The shield should be
grounded at only one point.
Cable Anchoring
After mounting the transmitter, the cable should
be anchored to reduce stress at the cable
terminations. When securing the cable, leave
enough slack to allow free movement of the
transmitter.
