Output Channel
Switch Setting
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
Visual Carrier
Frequency (MHz)
55.25
61.25
67.25
77.25
83.25
175.25
181.25
187.25
193.25
199.25
205.25
211.25
121.25
127.25
133.25
139.25
145.25
151.25
157.25
163.25
169.25
217.25
223.25
229.25
235.25
241.25
247.25
253.25
259.25
265.25
271.25
277.25
283.25
289.25
295.25
301.25
307.25
313.25
319.25
325.25
331.25
337.25
343.25
349.25
355.25
361.25
367.25
373.25
379.25
385.25
391.25
397.25
403.25
409.25
415.25
421.25
427.25
433.25
439.25
445.25
451.25
457.25
463.25
469.25
475.25
481.25
487.25
493.25
Frequency
Offset (kHz)
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
±12.5
±12.5
±12.5
NONE
NONE
NONE
NONE
NONE
NONE
NONE
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+25
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
+12.5
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
Output Channel
Switch Setting
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
Visual Carrier
Frequency (MHz)
499.25
505.25
511.25
517.25
523.25
529.25
535.25
541.25
547.25
553.25
559.25
565.25
571.25
577.25
583.25
589.25
595.25
601.25
607.25
613.25
619.25
625.25
631.25
637.25
643.25
91.25
97.25
103.25
109.25
115.25
649.25
655.25
661.25
667.25
673.25
679.25
685.25
691.25
697.25
703.25
709.25
715.25
721.25
727.25
733.25
739.25
745.25
751.25
757.25
763.25
769.25
775.25
781.25
787.25
793.25
799.25
805.25
811.25
817.25
823.25
829.25
835.25
841.25
847.25
853.25
859.25
Frequency
Offset (kHz)
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
+25
+25
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
NONE
TABLE 1: CATV
CATV
+100
CATV
BC
TV
CATV +100
CATV
+100
CATV
BC
TV
CATV
+100
CATV
BC
TV
MODULATOR UNITS
(Fixed channel and/or Agile types)
AUDIO INPUTS
VIDEO INPUTS
AC POWER
CORD
DC POWER
CABLE
Figure 4
SYSTEM OUT
RF COMBINER
maintain a ±1 dB variation of adjacent channel
carriers. Aural/Visual (A/V) ratios should be
held to -15 dB or less. The output ‘RF’ and ‘A/V
(Ratio)’ controls are used respectively to make
these adjustments.
RACK MOUNTING
Adequate ventilation is very important in
multi-channel installations. The RMM12 or
RMM4 cages should be spaced apart vertically
by at least one rack unit (1.75") height wherever
possible. Some air movement is mandatory in
enclosed rack cabinets. Excessive heat will
shorten component life and modulator perfor-
mance will be degraded without proper cooling.
CONNECTIONS AND CONTROLS
All connections to and from each modulator are
made through the rear panel. Figure 4
illustrates an installation with (12) modulator
units combined through a passive signal
combiner. Additional channels can be added by
using additional fixed channel or agile type
modulators and either multi-port combiners or
combinations of two-port combiners.
INSTALLATION NOTES
Level adjustment provides optimum
performance in multi-channel installations.
The modulator outputs should be checked
periodically with a spectrum analyzer to
POWER SUPPLY REQUIREMENT
Power for modulators mounted in the RMM12
rack mounting cage is to be supplied by a
Drake model PSM121 power supply. Up to 12
modulators may be powered.
The power supply in the four position rack
system can power up to four VMM860AG or
VMM860AS modulators or any mix of fixed and
agile VMM models up to four total modulators.
FREQUENCY CHART
The chart on the following page shows the
standard CATV channel coverage for these
agile models. Where an offset is indicated, this
amount of positive frequency offset is added to
the frequency indicated in the middle column.
As shown, this occurs only on channels
required to be offset by the FCC.
HRC or IRC frequencies can be set by means
of an internal jumper. See Figure 3. No jumper
will result in the STD channel plan selection.
CATV CHANNEL OUTPUT FREQUENCIES 5
4
INSTALLATION
