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
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
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
MODULATOR UNITS
(Fixed channel and/or Agile types)
AUDIO INPUTS
VIDEO INPUTS
AC POWER
CORD
DC POWER
CABLE
Figure 4
SYSTEM OUT
RF COMBINER
CATV CHANNEL OUTPUT FREQUENCIES 5
4
INSTALLATION
TABLE 1: CATV
CATV
+100
CATV
BC
TV
CATV +100
CATV
+100
CATV
BC
TV
CATV
+100
CATV
BC
TV
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. Units should be
spaced apart by at least one panel height
wherever possible, and some air movement is
mandatory in enclosed rack cabinets.
Excessive heat will shorten component life and
modulator performance 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
This VMM806AG agile modulator requires more
current than the fixed channel units. Therefore,
new 12 position rack installations with multiple
VMM806AG modulators (up to 12) must use the
Drake PSM121 (or equivalent) high capacity
power supply module (4.5 A rating @ 5 VDC
and 3 A @ 12 VDC).
If you are retrofitting a 12 position rack
installation and replacing only one of 12 fixed
channel modulators with the VMM806AG agile
unit, you may continue to use the standard
capacity power supply.
If more than one VMM806AG unit will be used,
the power supply module must be upgraded to
the high capacity PSM121, if not already in
place.
The power supply in the four position rack
system can power up to four VMM806AG
modulators or any mix of fixed and agile VMM
models up to four total modulators.
