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b.
Connect the Model 670HM to the Model 71
7
A by
pluggi
ng the
out
-
put cable (the other
e
nd of which is
a
ttached into the
Model 670HM
oscillator)
into
t
he te
r
minal
assembly
on the Model 717A control
panel.
c.
Plug the power
cable (connected to
the Model
717A
on
the
rear of
the
instrument) into a power source
(
115
-
volt,
50
-
60 cycle).
Turn
the POWER
switch to
the
on position
.
d.
Set BEAM
VOLTS at
800
,
MOD
,
SELECTOR
at
CW
.
e.
Set REFLECTOR RANGE at 600
.
L
Set
BEAM
VOLTS at
proper
v
oltage
(1,
000
volts
for the Model
670HM
;
see T
a
ble at end
of
section for
beam
voltage
for
the
other
oscillators
)
.
g
.
On
the Mod
e
l 6
7
0HM
,
s
e
t the FREQUENCY
-
KMC
dial
at 7.
5 kmc.
h
.
Adjust
BIAS
VOLTS to
obtai
n be
a
m
c
urren
t
of 20
ma
,
with
the MOD.
SELECTOR
s
wi
tch (on Model 717
A)
in the CW
position
.
i.
On
the Model 6
7
0HM
,
set the
SELECTOR
switch at
MANUAL
.
j
.
Set MOD
.
SELECTOR
(
on Model
7
17A) to
G
-
INT
.
MOD
.
k
.
Set
MOD
,
AMP
.
(on Model 71
7
A
)
to
approx
imately
full
clockwise
po
s
ition
.
Waveguide
-
The
next
s
t
ep
is t
o assemble the
wavegui
d
e, i
n the follow
i
ng
se
-
quence
:
2
1
.
To a
Mode
l X
7
5
2
D
(2
0
-
db
)
D
ire
c
t
i
on
a
l Coupler conne
c
t a
Model X752C
( 10
-
db)
Di
re
c ti ona
l
Coupler
,
b
ack
~
to -b
ac
k
.
The
Model
X752D coupler
samples the
i
n
ci
d
e
n
t
p ower
;
t
h
e
M odel X75 2C coupler s
a
mples the re
-
flected power
.
NOTE
:
A
1
0
-
db d
i
r ectional
c
oup
ler
m
a
y be us
e
d to
sam~le
the
incident
power, if
d
esire
d
,
b
ut a
n
a
d
vanta
ge
i
n accuracy may be
ga
ined
b
y
th
e
u
s
e
of a 2
0
-
db
c
oup
ler i
n the
i
n
ci
dent
channel of
the
system
.
2
.
Connec
t a Model X281
A W
ave
g
u
i
d
e
t
o
Coa xia
l Adapter
t
o the
i
nput
to
the
incident
couple
r (
Mod
el
X
752
D
)
.
NOTE
:
If a w
a
v egui
d
e attenuat
o
r i
s beingu
s
ed(Model
X382A
,
X370B
or C
,
o
r
X
37
5A
),
conne
ct
the attenuator
between
the
Model
X
28 1A
Wave gu
i
d
e
to Coaxial Adapter and
t
he
input
to
the in
-
ciden
t
c
oupl
er (
Mod
e
l X75
2
D
)
.
Set
the waveguide attenuator
for
1
0
-
20 db loss
.
3.
Connect the unkno
wn
lo
a
d to the ou tput o
f
the reflected coupler
(Model
X
7
52C
).
See Possible Errors
if
Input
Powe
r
to
Detector
Too
High
and
Spurious Signals
Due to Detector
Mismatch
, below.
-
13
-
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