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HD1 & HD2 - Antenna A and B Power - Activate/Disable
Jumpers
HD1
and
HD2
(both three pin headers) activate or disable power on the feedline to
INPUTs A and B.
HD1
is in the front corner of the circuit board directly behind the PHASE control and BAND
toggle switch. This header controls power to the INPUT A port. When this
jumper is on the middle and forward pins, power is OFF to INPUT port A as
shown in
Figure 1
. When this jumper is moved and connects the middle and
rearmost pins, power is applied to INPUT port A.
HD2
is along the edge of the board directly towards the rear from HD1. This header controls
power to INPUT port B. When this jumper is on the middle and forward pins,
power is OFF to INPUT port B as shown in
Figure 1
. When this jumper is
moved and connects the middle and rearmost pins, power is ON to INPUT
port B.
Note:
During TX Mute activation, power to the active antennas is disabled
regardless of the Antenna Power jumper settings.
HD4 - Antenna Power Source
The
HD4
jumper determines the source of active antenna power, either through the
NCC-1
power supply or the
ANT PWR
jack on the rear panel. HD4 is a three pin header located at the
rear of the main circuit board near the power jacks and the two large power
transistors that are bolted to the main circuit board. When the jumper on
HD4 is positioned on the middle and 12V pins (factory default position), as
shown in
Figure 1
, antenna power comes from the
NCC-1 main power supply. When the
jumper on HD4 is positioned toward EXT, the antenna port power comes from the
ANT PWR
jack. Only when an alternative power source is used for active antenna devices powered via
feedline connected to INPUT A and B, should the HD4 jumper be set to EXT.
HD5 - TX Mute Polarity
HD5
controls the logic state that activates the TX Mute polarity function and is located just
below the rear panel Ext Control connector. HD5 is a four pin header.
When HD5 has two pin jumpers in both positions completely filling
the header, operation is normal.
A logic low activates the TX Mute.
This means any voltage above 3 volts positive or an open circuit allows the
NCC-1
to function
normally. Power is available for use at antenna ports.
Anything below 1 volt positive (including a "Ground on Transmit") causes the
NCC-1
to mute.
Power is removed from the antenna ports and the INPUT
A
port is connected directly to the
receiver port. Switching time is about 2 ms.
