Attenuator Probe, Showing Pickup - HP 608E Operating And Service Manual

•
Model 608E/F
RF OUTPUT
CONDUCTOR
(SOFT SOLDER)
C69
MOUNTING STRAP
~~~(j~
--GROUND SIDE
Section V
C37
SLUG OF
IMPEDANCE
ADJUSTING
CAPACITOR
RF OUTPUT SIGNAL
PICKUP lOOP
RS9 RSS
(SOFT SOLDER)
-----~---------
IMPEDANCE MATCHING NETWORK
-Figure 5-26. Attenuator Probe, Showing Pickup Loop and
Impedance Matching Network
CAUTION
Under no circumstances should the probe be
forced into the housing.
f. Connect a power meter (such as Model 432A),
through a thermistor mount (Model 478A or equivalent),
to RF OUTPUT connector.
b.
Replace split drive screw in probe, making cer-
tain that screw slot is parallel to axis of housing.
c. Set attenuator drive cable
in
screw slot and re-
place both washers and nut. Do not tighten nut. Cable
must move freely through the slot until probe pene-
tration has been set.
d. Secure RF cable to clamp on side gusset.
e. Connect instrument to a source of lI5-volt for
230 volt) power, and turn on POWER switch. Unless
otherwise specified, operating controls should be set
as follows:
•
,
'- ..
MODULATION Selector
Frequency dial . . . .
FREQUENCY RANGE .
AMPL TRIMMER. Adjust for max.
RF OUTPUT meter . .
MODULATION control.
Attenuator . . . . . .
cw
70 MHz
band C
RF output
7 dBm
max. ccw
o
dBm
g.
Remove RF Generator side plate so that clear-
ance between attenuator probe and coils of RF Am-
plifier tank may be observed.
CAUTION
The following step must be executed as care-
fully as possible to insure that the pickup
loop does not make contact with any of the
power amplifier coils. These coils are at
B+ potential, and contact between anyone of
them and the attenuator pickup loop will
damage attenuator components.
h. With attenuator dial set exactly on
0
dBm, man-
ually advance attenuator probe into the hOUSing until
RF output signal is exactly
1
milliwatt
(0
dBm) as read
on external power meter.
5-31