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Operation
For two antennas with approximately equal desired signal levels, or for two antennas with
approximately equal undesired signals or noise levels.
1. Connect the
NCC-1
to your station and a suitable power source.
2. Set the front panel controls as follows:
A.
Both
A
and
B
attenuator switches to the
0
dB position, unless one antenna requires more
preset attenuation
B.
BALANCE
control to the center position, the knob indicator line should be centered
vertically
C.
PHASE
control rotated to zero position
D.
INPUTS
switch to
NORM
E.
B PHASE NORM-REV
switch set to
NORM
F.
BAND
switch to
L
for operation below 5-10 MHz or
H
for operation above 5-10 MHz. In
the range of 5-10 MHz, either setting may work
G.
POWER On
To get the best rejection of unwanted signals or noise, rotate the PHASE control until the noise or
interference is at the lowest level. If a null cannot be found, change the PHASE NORM/REV switch
to the REV position. The null might be shallow until levels are balanced.
Adjust the BALANCE control to further reduce noise or interference. It may be necessary to go
back and forth between PHASE and BALANCE controls a few times. If the BALANCE control is
not within 90 degrees of the center position, apply attenuation to the opposite channel that the
BALANCE pointer is on. This should center the BALANCE control indicator line, or it may reset
the balance point to the opposite side of the control if the antenna's signal difference is between 3 to
9 dB. If one antenna is always 3 to 12 dB different than the other, then either the weaker antenna
should be improved, or the stronger antenna may be attenuated with a 3 or 6 dB pad to provide a
better balance between sources. Without precise signal or noise level balancing between antenna
INPUTS A and B or cancelling will not be as deep as possible.
Often a little experimentation is required to get the best performance using different selections of
available antennas and phase relationships. You can also reverse directions by changing INPUT A
and INPUT B using the INPUT switch. This switch is most useful when elements are in line with
