Fairhaven RD500 User Manual - 4.2
LPF is a steep, low pass filter circuit which can improve signals that are subject to a
high degree of noise.
AVC (automatic volume control)
Aux Key 5.
This facility acts as an audio compressor, which can reduce audio level variations
when listening to signals that are subject to fading. It works by augmenting the AGC
system (which is carrier derived), by feeding back the audio signal level to the AGC
system.
MORE
Aux Key 6.
Provides access to the next part of the menu.
Option 1. Reserve memory
This allows the receiver’s memory to be partitioned to provide space for audio
recording, see section 4.14
ALTERING THE MEMORY PARTITION WILL ERASE ALL MEMORIES.
Option 2. Free record count
The free record counter shows the remaining number of empty records that are
available for use.
We now return to the main shift key facilities on the receiver, press cancel.
4.2
BP (stereo CW) filter
These filter options are active when CW is selected from the mode menu. If BP
(bandpass) is selected the filters spread the audio spectrum into a stereo panorama,
which gives spatial separation to C.W. signals. This makes it easier to focus upon
individual signals, those that are lower than the filter frequency appear to the left, and
frequencies that are higher than the filter roll off appear to the right. The filter can be
peaked at 850Hz in 3 selectable bandwidths (Keys 4,5 and 6).
A low pass filter option (LP) is also provided this gives mono audio which is
rolled off at 850Hz, peaking the filter by selecting narrower bandwidths, gives a
conventional band pass filter shape. See appendix for filter shape table (section 8).
CW filter display
CW F i l t 1 [LP] 2 BP