Option Installation
Page 5-12
Owner’s Manual
TVM450/S/TVM550/S/TVM550II/TVM550IIS
CALT45
The CALT45 is an optional, vertically mounted PC board that provides an
ALTERNATE COMP (composite) IF IN input to the TVM-series modulators, except
when the CIF450-1 option is installed. The CALT45 module is designed primarily to
give users the option of quickly switching to an alternate receiver/modulator combina-
tion on numerous channels for civil defense or other time-critical reasons.
Switching to ALTERNATE COMP IF occurs either automatically or manually.
Automatic switching occurs when the ALTERNATE COMP IF input level reaches
30 dBmV
±
3 dB. Manual switching occurs when the REMOTE IF SELECT
switch closes to ground, regardless of level.
CALT45 Installation Notes
The CALT45 board mounts vertically in the TVM-series modulators between the
unit rear panel and the up/down RF converter module. Because of the proximity
of other boards, complete the cable connections before installing the board.
Make sure the component side of the CALT45 board faces the unit rear panel.
NOTE
The CALT45 has a built-in CBP45. The CALT45 is not compatible with
TVM-series modulators containing a CIF450 composite loop kit or a CBP45
or CBP45-1 filter module and loop connectors.
Later TVM450 and TVM550-series units have both an auxiliary IF opening and a
remote control opening in the rear panel. Earlier TVM450 units do not have the
auxiliary IF opening. If a TVM450 does not have an auxiliary IF opening in the
rear panel, drill a standard F-type connector hole (7/16-inch) one inch directly to
the right of the REMOTE IF SELECT hole (between the REMOTE IF SELECT
hole and the VISUAL IF IN hole).
Test points TP02/TP03 on the CALT45 board may have to be unsoldered to
match the attenuation of the TVM IF combiner board.
CALT45 Parts Needed
•
1
TVM450- or TVM550-series modulator
•
1
CALT45 option kit
CALT45 Installation
1. Verify that the CALT45 option kit contains the parts shown in Figure 5-11.
