Orban OPTIMOD 8400 - 8400 FRONT PANEL

2-12
INSTALLATION ORBAN Model 8400
Circuit Ground
To maintain the same potential in all equipment, the circuit (audio) grounds must be con-
nected together:
• Circuit and chassis ground should always be connected by setting the 8400’s
Ground
Lift
switch to its GROUND connect position, except when the 8400’s stereo encoder is
driving an unbalanced exciter input. (Many older exciters have unbalanced inputs.)
This is an unbalanced-to-unbalanced connection, so set the 8400’s
Ground Lift switch
to
LIFT to break the ground loop that would otherwise occur.
Alternately, you can balance and float the exciter input with the Orban
CIT25 Composite Isolation Transformer—see page 2-10.
• In high RF fields, the system is usually grounded through the equipment rack in
which the 8400 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.
8400 Front Panel
• Headphone Jack allows you to monitor the output of the processing through head-
phones. Headphone impedance should be 75Ω or higher.
If the HD option is installed, you can switch the headphone feed between the
output of the digital-channel processing chain and the signal driving the FM
processing’s analog output. Otherwise, the headphone jack carries the signal
driving the FM processing’s analog output, which can be switched between
the output as processed for transmission and a low-delay monitor output.
• Headphone Level Control (the small blue control knob to the right of the jack) ad-
justs headphone output.
• The red Enter button allows you to choose pop-up menu items, icons and buttons. If
you are in the Preset screen, it allows you to put a Factory or User Preset on-air once
you have selected it.
If you edit a Factory Preset, you must save it as a new User Preset to retain your edit
permanently. Your edited preset will automatically be retained without saving even if the
8400 is powered down and will be restored on-air upon power-up. Your edited preset will
also appear in the RECALL list of available presets as the name of its parent present pre-
fixed by the letter “M” (for “modified”).
However, if you edit another preset, your old edited preset will be lost—the 8400 auto-
matically retains only one “modified” preset. Therefore, it is wise to rename and save any
edited preset you wish to keep, using the 8400’s SAVE main menu item. This ensures
that your edited preset will not be overwritten accidentally.