Model 4342A
Section V
Paragraphs 5-l to 5-8
SECTION V
MAINTENANCE
5-1. INTRODUCTION.
5-2. This section provides the instructions
and information required to maintain the HP
Model 4342A Q Meter. Included are Performance
Checks, Adjustment and Calibration Procedures,
Servicing and Troubleshooting guides.
5-3. TEST EQUIPMENT REQUIRED.
5-4.
The equipment required to maintain the
Model 4342A are listed in Table S-l. The
table lists the type of equipment to be used,
the performance requirements and recommended
model. If the recommended model is not
available, equipment which meets or exceeds
the critical performance may be substituted.
5-5.
Q ACCURACY CONSIDERATIONS.
5-6. A Q Meter theoretically measures the
comprehensive Q of a circuit. In practice,
residual circuit parameters, which do not
exist in ideal circuits, contribute to meas-
ured Q values.
Insertion resistance, residual
inductance in series with the COIL terminals,
Table 5-2. Q Correlation Factors.
30
MHz
1.17
45
MHz 1.37
* Correlation Factor x Indicated Q - Value on513/
518 = 4342A Indicated Q-Value.
Q voltmeter input conductance, and tuning
capacitor loss are some of the factors that
contribute to measurement errors in the prac-
tical measurement of Q in a typical circuit.
These errors can be minimized by the use of a
low output impedance injection transformer
system,
a low loss tuning capacitor, and a Q
voltmeter which has a low input conductance,
as in the Model 4342A. Consequently, the
4342A will indicate higher Q values than
other currently available Q meters.
By assuming that no internal circuit loss
exists in the Q Meter, the specified Q ac-
curacy can be guaranteed by performing the
adjustment and calibration procedures in this
section.
If a Q calibration, which takes the
actual internal loss of the instrument into
account is required, a Q value reading check
with Q standards (inductors) should be done
in addition to the adjustment and calibration
procedures described in paragraphs 5-9 and
those which follow.
At the present time, no Q standards are
available for users, thus a Q accuracy check
with Q standards can not be performed at the
facility where the instrument is used. Since,
Hewlett-Packard, however, maintains Q standards
traceable to NBS (National Bureau of Standards)
in its major service offices, a calibration
service with authorized Q standards for the
4342A is always available. If a Q accuracy
check is needed, contact your nearest Hewlett-
Packard office. If HP Models 513A/518A Q
standards are owned and maintained, a Q ac-
curacy check for the 4342A can be done at the
user’s location. Refer to Table 5-2 for Q
Correction Factors.
5-7.
OPTION.
5-8. The calibration and adjustment pro-
cedures for Option 001 instruments (that
differ from the standard Model 4342A) are
provided in paragraphs 5-25 and below.
5-1
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