Circuit Ground; Studio Level Controller Installation (Optional); If You Are Using Orban 8200St Studio Level Controller - Orban OPTIMOD 6300 Operating Manual

OPTIMOD 6300 DIGITAL

Circuit Ground


To maintain the same potential in all equipment, the circuit (audio) grounds
must be connected together.
The 6300's circuit and chassis ground are internally connected; there is no
"ground lift" switch. This should never cause a problem with noise or
ground loop hum if the 6300's is connected to other equipment via bal-
anced connections.

In high RF fields, the system is usually grounded through the equipment rack in
which the 6300 is mounted. The rack should be connected to a solid earth
ground by a wide copper strap—wire is completely ineffective at VHF because of
the wire's self-inductance.

Studio Level Controller Installation (optional)

[Skip this section if you are not using a studio level controller ahead of the 6300.
Continue with "Quick Setup" on page 2-12. Note that this section has nothing to do
with using the 6300 itself as a studio level controller. If you are doing this, see Using
OPTIMOD 6300 as a Studio Level Controller on page 1-10.]

As of this writing, the currently manufactured Orban products that can be used
as external AGCs are Optimod-PC 1101 and Optimod 6300. Their manuals con-
tain instructions on how to use them in this application. They are the preferred
choices because their AGCs are identical to the AGC in the 6300.

Discontinued Orban products usable as external AGCs include the 8200ST, 464A
"Co-Operator," 8100AST, and 1100 OPTIMOD-PC. In this manual, we do not pro-
vide step-by-step instructions for setting up all of these older products, although
it should be easy to extrapolate from the instructions we do provide.

If you are using Orban 8200ST Studio Level Controller

If the STL uses preemphasis, its input preemphasis network will probably introduce
overshoots that will increase peak modulation without any increase in average
modulation. We therefore strongly recommend that the STL transmitter's preem-
phasis be defeated (freeing the STL from such potential overshoot), and that the
8200ST be used to provide the necessary preemphasis.
If the STL transmitter's preemphasis cannot be defeated, then configure the 8200ST
for flat output. In this case, average modulation levels of the STL may have to be re-
duced to accommodate the overshoots. These issues are extensively discussed start-
ing on page 1-9.
1. Configure the 8200ST's internal jumpers.
A) Remove all screws holding the 8200ST's cover in place; then lift it off.
2-9
INSTALLATION