Noise Blanking & Reduction; Diversity; Rit, Xit - Apache Labs ANDROMEDA ANAN-7000DLE MKII User Manual

6.4.4 Noise Blanking & reduction
Various means to reduce noise are available. Thetis has modern, powerful algorithms available to
optimise its performance. These controls can be accessed through the RX Menu.
NR Activates noise reduction, to minimise random noise. This attempts to reduce the
noise in the channel while preserving signal content.
Off:
NR:
NR2:
NB Activates the wideband noise blanker, to remove impulse interference.
Off:
NB:
NB2:
ANF Activates the Automatic Notch Filter. This filter will attempt to notch out interfering
carrier signals within the receiver passband.
SNB Activates the spectral Noise Blanker. The SNB detects impulse interference and
attempts to estimate the "correct" receiver signal during the presence of the impulse.
6.4.5 Diversity
Diversity allows the radio to implement beamforming. This requires two fully independent inputs,
one through each A‐D converter, from two antennas. This can be used to enhance a weak signal, or
to steer a null towards an interference source. Diversity improves the received signal for RX1, but is
independent of the operation of RX2. RX2 can be used on a different band if desired; the only
constraint is if it is on a different band, its RX filters will need to be disabled.
To use diversity:
1. Select the Menu > Diversity menu item to open the Diversity form or use the Diversity
button on the RX menu.
2. Set Receiver source to RX1 + RX2
3. Set reference Source to RX1
4. To minimise interference:
a. Use the Diversity Phase (lower) encoder to move the dot around the display
b. You should see the panadapter noise floor move up and down as you drag
c. Find the angle giving minimum noise floor
d. Keeping the mouse at that angle, Use the Diversity Gain encoder to find the
optimum amplitude with minimum noise
e. If you aren't able to get a minimum: Set reference Source to RX2 and try again
5. To maximise strength of one signal:
a. Use the Diversity Phase (lower) encoder to move the dot around the display
b. Find the angle giving maximum signal on the panadapter for the wanted signal
c. Keeping the mouse at that angle, Use the Diversity Gain encoder to find the
optimum amplitude with maximum signal
d. If you aren't able to get a maximum: Set reference Source to RX2 and try again
6. To turn diversity off, Click Enabled and it will turn to a red Disabled button.
6.5 RIT, XIT
RX and TX independent tuning allows you to adapt the radio to remote stations that are not tuned to
the exact same frequency. RIT and XIT are controlled by an encoder whose function can be set to off,
RIT or XIT. Indicators show which is active.
ANDROMEDA Manual
Noise reduction inactive
Activates the LMS noise reduction algorithm
Activates the spectral noise reduction algorithm
Noise Blanker inactive
Noise Blanker active, and sets receiver input to zero during impulse
Noise Blanker active, and estimates the signal the receiver would
have seen during an impulse.
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