AOR SDU-5500 Operating Manual

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Use the spin wheel dial to so that the required ICOM radio is highlighted then press .  The legend
“IC-R8500 Connected” (or whichever radio is specified) will briefly be displayed then the CF readout will
display the current receive frequency of the radio.  Should any fault occur in connection with the
companion radio at this stage, the SDU5500 CPU will identify the receiver as “Other” being connected.
In this case check the radio parameters (baud rate setting etc) and leads then try again.
Warm Start
Once the SDU5500 has been configured following a cold start, it will not be necessary to enter the
companion radio details again as long as the SDU5500 remains connected to power (presuming that
you wish to continue using the same companion radio type)... even after the SDU5500 has been
switched off and back on again.
Cold start / Hot start
The initial display which appears on the screen after switching on depends on whether the SDU5500 has
remained connected to a power supply since last use.  When the cold start is performed (if power has
been removed), the SDU5500 will start with menu page 1 while menu page 4 will appear when the
SDU5500 is hot-started.  Either way, shuttling from page-to-page is possible.
General operational notes
The ICOM receiver will now be operated from the front panel of the SDU5500, receive frequency and
mode may be controlled.  The receive frequency and receive mode may still be selected from the radio
controls.  The minimum specified tuning step size is 100 Hz, any digits below 100 Hz will be ignored.
Note: If the ICOM receivers use a mode not supported by the SDU5500, the legend “NFM” will be
displayed.
Passive band scope
Should you prefer to operate the companion radio totally from it’s own front panel, it is possible to
configure the SDU5500 for “Other” companion radio and use the display unit as a band scope only.  The
Centre Frequency will then always be displayed as 10.7 MHz but an OFFSET will be displayed making
the measurement of interesting traces possible.
4-4  Operation with an “Other” companion receiver
The SDU5500 is designed to work with any companion radio which is equipped with a suitably wide
10.7MHz IF output of sufficient drive level.  If you are using such a receiver which is not included in the
SDU5500 supported companion radio list, the following procedure should be observed.  Make sure that
both the SDU5500 and companion radio are switched off.
•Connect a suitable power supply using the d.c. lead provided.  Ensure the correct polarity is observed,
the stripe signifies positive.  (In certain market areas, a suitable power supply may be provided).
•The RX CTR socket of the SDU5500 is not used as direct control of the companion radio’s controls is
not possible.
•Connect a 50 OHM patch lead between the RF IN BNC socket of the SDU5500 and the IF OUT socket
of the companion radio.
•Switch on the companion radio.  Now switch on the SDU5500.
The ‘cold start’ sequence does not apply as the SDU5500 will default to ‘Other’ receiver when a
supported radio type is not detected.  The SDU5500 LCD will display various details.  Under the item
“RX” (third line down from the top left of the LCD), “Other” radio will be displayed with the CF (centre
frequency) of 10.7 MHz.
It is a good starting point to ensure that menu  “1” is displayed in the lower left corner of the LCD so that
you know where your are each time the SDU5500 is powered up, this is what happens by default.
Section 4-3-2, 4-4 
						

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Reprogramming the 10.7 MHz IF
It is possible to use a companion radio with an IF not of 10.7 MHz but within the range of 5.7 to 15.7
MHz by reprogramming the IF frequency employed by the SDU5500 to a resolution of tens of Hz.
Sweep direction is selectable depending on the heterodyne configuration of the radio, however the
maximum sweep span may be narrower than 10 MHz due to the IF characteristics and centre frequency
of the companion radio.
Usefulness
In order to provide a useful bandwidth of at least 1 MHz (± 500kHz), as a rule of thumb, the limits of IF
should be considered as 6.7 to 14.7 MHz.
Limitations in respect of maximum span
A span of 10 MHz (± 5 MHz) is only possible when the IF is set to 10.7 MHz.  When a different IF is
reprogrammed, the maximum span width is reduced by twice the difference between 10.7 MHz and the
new IF.
1) For example, if a new IF of 13 MHz is employed, the maximum span can be calculated as follows:
13 - 10.7 = 2.3
2.3 x 2 = 4.6
10 - 4.6 = 5.4 MHz
So the maximum span width would be 5.4 MHz (± 2.7 MHz)
2) For example, if a new IF of 7.3 MHz is employed, the maximum span can be calculated as follows:
10.7 - 7.3 = 3.4
3.4 x 2 = 6.8
10 - 6.8 = 3.2 MHz
So the maximum span width would be 3.2 MHz (± 1.6 MHz)
& Important note: When reprogramming the centre frequency, first set SPAN width to 1 kHz prior to
reprogramming to ensure that the selected span band width is always valid or reprogramming will not be
possible, as span width defaults to 10000 kHz (10 MHz).
Set the span width to 1 kHz by selecting menu 4.  Press  SPAN  then press 
 then press .
The LCD will confirm selection as “SPAN : 1kHz” on the LCD.
Staying with menu 4, select the centre frequency menu by pressing  CF   Key in the IF of the
companion radio, for example, if using a Kenwood TS870S, an IF of 8.83 MHz is required.
Key 
    then press 
The LCD confirms selection of the new IF frequency “CF : 8.83000MHz”
The maximum span width will be:
10.7 - 8.83 = 1.87
1.87 x 2 = 3.74
10 - 3.74 = 6.26 MHz
So the maximum span width will be a
respectable and useful 6.26 MHz (± 3.13 MHz)
Try it out, you may select a span of 6260kHz maximum, an error beep is emitted if you attempt to enter a
figure greater than this ! The Kenwood TS870S offers unity gain between aerial input and I.F. output
resulting in good dBm accuracy of a few dB in the range of -90 to -40dB with MDS around -100dBm
(2uV).
Section 4-4 
						

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(5)  General operation of the SDU5500
There are effectively two methods of operation when companion radios are connected to the SDU5500:
1. Active mode, the radio is controlled from the SDU5500 in SPECTRUM, STEP
 RESOLUTION or CHANNEL SCOPE mode.
2. Passive mode, the SDU5500 does not control the radio, only the IF output is connected
between the SDU5500 and companion radio providing a bandscope of the receiver’s
passband.
5-1  Using the SDU5500... sequence to use
Connect-up the SDU5500 and companion receiver as indicated in section 4 of this operating manual.
Switch on the radio followed by the SDU5500.  The correct companion receiver should be displayed
near the top-left of the LCD beside the legend “RX”... for instance “RX : AR5000”.
Select menu 1... mainly sets the companion radio type and LCD
1 PREV RX PLOT CONT B/W NEXT
If you need to change the companion radio press  RX.  Use the spin wheel dial to select the
companion radio type AR5000, AR3000A, IC-R7100, IC-R8500, IC-R9000, Other.  Press 
 to accept
the changes.  If everything is correct the “Connected to” message briefly appears on the LCD followed
by the standard LCD with the legend “RX” confirming the companion radio type.
If you wish to change the plot mode between paint (default) and outline, press the  PLOT  key as a
toggle.  The changes are obvious and are confirmed by the “PLOT” legend.
If you wish to change the LCD contrast (for different viewing angles) press  CONT  to access the
contrast menu.  Use the spin wheel dial to select the best value between 0 - 160.  Press 
 to accept
the changes.
If you wish to swap the display between light-on-dark and dark-on-light press  B/W  which acts as a
toggle.
Select menu 2... mainly sets the companion radio receive mode, tuning step etc.
2 PREV MODE STEP ATT GAIN NEXT
If using “Other” companion radio: 2 PREV - STEP  - GAIN NEXTIf using channel step mode: 2 PREV MODE - ATT GAIN NEXT
If you wish to change receive mode, press  MODE  and use the spin wheel dial to select the receive
mode from those available on the menu (in the case of the AR5000: WFM, NFM, AM, LSB, USB, CW,
AUTO).  Press 
 at accept the selection.  The legend “MODE” confirms receive mode of the
companion radio.
If you wish to change the receiver tuning step, press  STEP  and key the desired tuning step in kHz
format (in the case of the AR5000: between 0.01 kHz and 999.95 kHz).  The  BS  key may be used as
BACK-SPACE to correct a mis-key and  ESC  may be used to exit the menu without alteration.  Press
 to accept the selection. The legend “STEP” confirms the tuning step of the companion radio.
Section 5, 5-1 
						

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If you wish to toggle the attenuator on / off, press  ATT   This affects the gain at the receiver’s front
end and sensitivity of the companion radio.  The legend “ATT : ON / OFF” confirms attenuation setting of
the companion radio, this is not available in ‘Other’ radio operation.
If you wish to toggle the SDU5500 input gain, press  GAIN   This affects the gain of the SDU5500
and has no effect on the sensitivity of the companion radio.  The base line of the SDU5500 is equivalent
to -40dBm in HIGH and -10dBm in LOW. The legend “GAIN” confirms the status of gain setting.
Select menu 3... selects SDU operating mode
3 PREV SPECT STRES CHANL - NEXT
If using “Other” companion radio: 2 PREV SPECT STRES - - NEXT
For normal spectrum analyser operation, press  SPECT , this is the default.  Use this key to return
from STRES (step resolution mode) or CHANL (channel scope mode).  The legend “OP.MODE” confirms
current selection.
To activate step resolution mode, press  STRES .  In ‘step resolution mode’, ONLY the wanted steps
are checked for activity rather than the whole band, this is particularly useful when you know the tuning
steps used on a particular band and don’t want to view in-between the channel allocations.  To achieve
this, the LCD-step is automatically forced to equal the tuning step of the companion radio.  You cannot
manually set the SPAN, by necessity it has to be calculated by the SDU5500.  STRES mode is
confirmed by the legend “OP.MODE : STRES” on the LCD.  To return to a standard spectrum analyser
display press  SPECT
& NOTE: Please refer to section 5-3 for specific instructions for step resolution mode operation.
To activate Channel Scope mode, press  CHANL   In ‘channel scope mode’, you may view a defined
bandwidth up to a maximum span of 5 MHz minus one step.  In particular, channel scope mode is very
useful for viewing relatively narrow bands of a couple of MHz.  ONLY the wanted steps are checked for
activity and as a narrower span is specified, screen refresh can be significantly faster than sweeping a
whole 10 MHz bandwidth.  To achieve this, the LCD-step is automatically forced to equal the tuning step
of the companion radio.
When channel scope mode is run for the first time, a menu is presented prompting you to input three
values to define operation:
1) Channel Scope Start Freq (MHz)... enter the
required lower band edge frequency using MHz
format then press 
2) Channel Scope Step Freq (kHz)... enter the
required channel step using kHz format then press
3) Channel Scope End Freq (MHz)... enter the
required upper band edge frequency using MHz
format then press 
& Note:  The MAXIMUM bandwidth is
5000 kHz (5 MHz) minus one channel step.
Section 5-1 
						

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The receive frequency is NOT the centre frequency of display but is equal to the START frequency, a
pair of ‘outline triangle legends’ (above and below the graphical start frequency) indicate the receive
frequency.
CHANL mode is confirmed by the legend “OP.MODE : CHANL” on the LCD.  To return to a standard
spectrum analyser display press  SPECT
Reprogramming channel scope mode:  Next time channel scope mode is used, the previous
parameters will be employed unless they are redefined using the “FREQ” key of menu 4 (which replaces
the menu item “CF” while using channel scope mode).
& NOTE: Please refer to section 5-4 for specific instructions for channel scope mode operation.
Select menu 4... selecting centre frequency, span and resolution
4 PREV CF SPAN RBW - NEXT
If using step resolution mode: 4  PREV  CF  STEP  RBW  -  NEXTIf using channel scope mode: 4  PREV  FREQ  -  RBW  -  NEXTIf using “Other” companion radio:  4 PREV CF SPAN RBW FDIR NEXT
To input the required centre frequency when in spectrum “SPECT” or step resolution “STRES”
modes, press  CF    Input the required frequency using MHz format then press 
.
This becomes the centre frequency of the LCD and the frequency which is monitored by the companion
radio.  To abort the frequency input menu press  ESC , to correct a mis-key press  BS  which will act as
a back-space.
The LCD legend “CF : 123.456” (with your frequency input selection) confirms operation and initially the
marker frequency (legend “Marker”) will equal the centre frequency.
Adjacent frequencies above and below the centre frequency will be displayed as a spectrum, the span
and step size will be as defined by ‘STEP in menu 2’, ‘SPAN of menu 4’ and ‘SPECT / STRES of
menu 3’.
& Note:  The centre frequency must be within the tuning range of the companion radio, in the case of
the AR5000 this is between 10 kHz (0.01 MHz) and 2600 MHz.
To change the total displayed bandwidth in spectrum mode, press  SPAN   In step resolution mode
this key is labelled “STEP” and in channel scope mode it is blanked.  Key in the required total bandwidth
using kHz format (the maximum bandwidth is 10000 kHz (10 MHz) followed by 
Section 5-1 
						

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Each LCD-STEP will equal the total bandwidth in kHz divided by 304 dots, in the case of 10000 kHz this
would represent 10000 / 304 = 32.89 kHz.
If you wish to have one LCD-STEP to equal one tuning step of the companion radio, you must use step
resolution mode or channel scope mode.
& Note: if using step resolution mode, the menu key “SPAN” is replaced by the “STEP” key.  If the
companion radio is set to “Other”, the centre frequency is automatically set to 10.7 MHz.  Please refer to
section 4-4 of this operating manual regarding operation with “Other” radio receivers and changing the IF
frequency used.
To change the Resolution Band Width sampling, press  RBW    Sampling may be ‘toggled’ between
 5 kHz and 30 kHz, different filters are used for each resolution.  While 5 kHz provides greater detail,
the refresh rate is slower, 30 kHz sampling refreshes more quickly but with lower resolution.  When the
companion radio is using larger tuning step sizes, 30 kHz is the best setting.  The legend
“RBW : 5 kHz / 30 kHz” confirms selection.
When using “Other” companion radio :FDIR
The SDU5500 is designed to use a 10.7MHz IF output taken from the superheterodyne receiver.
Depending on the receiver circuit design (whether upper heterodyne or lower is used for receiving
signals), the frequency spread of the SDU5500 may be reversed.  When connected with any supported
radio included, the SDU5500 will automatically adjust itself to the correct spread (lower frequency left to
higher frequency right on the screen).  When an unspecified radio (Other) is connected, you may have to
select the NORMAL/REVERSE position in order to get the correct spread.  In this case use the  FDIR
key to toggle between “Normal” and “Reverse”.  At other times the key legend will be BLANK.
Select menu 5... selecting the marker
5 PREV MKR PEAK CPEAK MK-CF NEXT
To select a standard marker display mode rather than ‘peak’ or ‘continuous peak’ press  MKR ...
this is the selection by default.  (i.e. returns the SDU5500 to ‘marker’ mode if ‘PEAK’ or ‘CPEAK’ have
been selected). The LCD legend “Marker” is displayed directly above the LCD graticule to confirm
operation.
To select ‘PEAK’ signal level press  PEAK   This freezes the current spectrum trace, capturing brief
transmissions.  The spin wheel dial may be rotated to ‘hop’ between the highest traces in sequence.
The LCD legend “Peak” is displayed directly above the LCD graticule to confirm operation.  To cancel
‘peak’ press  MKR  to return to marker mode.
To select ‘CONTINUOUS PEAK’ press  CPEAK    This is a similar facility to ‘peak’ but automatically
forces the marker to the highest peak immediately following a completed spectrum trace, however the
trace is refreshed every sweep.  In particular it is a very powerful aid when used in conjunction with the
MK-CF  key, this enables transmissions to be automatically detected and the companion radio placed
on the correct frequency simply by pressing the  MK-CF  key (marker to centre).  To cancel ‘peak’ press
MKR  to return to marker mode.
To force the ‘marker to centre frequency’ press  MK-CF    The marker may be moved using the spin
wheel dial (and automatically moved to peak signal using the ‘peak’ and ‘continuous peak’ facilities).
When the marker is forced to the ‘centre frequency’, the companion radio is also moved to the centre
frequency where the transmission may be monitored.
If step size has been selected appropriately, the exact frequency will be corrected to the nearest
increment (most appropriate receive frequency).
Section 5-1 
						

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& Note: If [MK-CF] is used with the companion radio set to “Other”, the IF frequency employed will be
changed from the default of 10.7 MHz.  In normal use, this should be avoided, however this may be
useful if the exact centre frequency of the companion radio is not known.
Select menu 6... analysis selection
6 PREV MAX AVR  -  - NEXT
To select  MAXIMUM trace, press  MAX    The maximum height of traces will be frozen on the display.
This will result in ‘peaks’ where transmissions have taken place, one side effect is that the baseline will
tend to build-up a 5 to 10dB solid bar due to random background noise.  MAX is a useful facility to ‘trap’
occasional transmissions over a long time-scale and to check on band allocation for transmission
licence issuers.  Press  MAX  a second time to restore a normal trace.  A reverse contrast “MAX”
legend confirms selection when in use.
To select  AVERAGE trace, press  AVR    The average height of traces are calculated and displayed
on the LCD.  This causes the display to be a little sluggish at detecting transmissions when they first
appear but permits them to remain visible for longer when the transmission stops.  The effect is a ‘wave’
of activity, useful for assessing band activity in a relatively short period of time.
Once activated, the buffer size must be allocated between 2 and 32 frames inclusive.  A reverse legend
“AVR” is displayed on the LCD to confirm operation.  While the buffer is loading, the number of frames is
indicated until the programmed number has been sampled, after this point the specified number of
frames will be averaged on an on-going basis.  Press  AVR  a second time to restore a normal trace.
A reverse contrast “AVR” legend confirms selection when in use.
Select menu 7... screen position
7 PREV  NEXT
In channel scope mode:  PREV  -    -  NEXT

Moves the centre frequency upward by half the span.  For example, if the span is set to 10000 kHz (10
MHz), the centre frequency will be increased by 5000 kHz (5 MHz)... so that a centre frequency of 123
MHz would become 128 MHz.
& Note:  Not available in channel scope mode.
Section 5-1 
						

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5-2  Spectrum analyser mode
The standard default mode used by the SDU5500 is spectrum analyser mode “SPECT”.
As an example of usage, monitor the FM broadcast band using spectrum analyser mode
with the AR5000.
1)  Connect the AR5000 with the SDU5500 referring
to section 4-1 of this operating manual.  First switch
on the AR5000 then the SDU5500.  Unless the
AR5000/SDU5500 combination has been previously
configured, the SDU5500 will default to “Other”
companion radio.
2)  Go to menu 1, use the  PREV   NEXT  keys or
press the numeric key 
  Push the  RX  key to
access the companion radio configuration menu.
Rotate the spin wheel dial to highlight “AR5000”
then press 
.
The message “AR5000 Connected” will be briefly
displayed on the SDU5500, if an error message “RX
Disconnected” appears, re-check the connections
and the RS232 parameters of the AR5000 (the
SDU5500 may try two or three times to connect to
the AR5000).  Other items such as  PLOT ,
CONT ,  B/W  can be ignored unless necessary.
The frequency sweep direction  FDIR  is default
and cannot be changed.
3)  Go to menu 2, use the  PREV   NEXT  keys or
press the numeric key 
. The  MODE ,  ATT
and  STEP  are automatically transferred from the
AR5000 to the SDU5500, however re-check the
attenuator setting.  Press  ATT  to toggle the
attenuator status, in this example switch the
attenuator off.  Push the  MODE  key to select
receive mode, in this example “WFM” followed by
.  Push  STEP  to enter the tuning step size in
kHz format, in this example of 100 kHz followed by
.   The  GAIN  key accesses the SDU5500
gain control, leave this in the default “Hi” (high)
position.
4)  Go to menu 3, use the  PREV   NEXT  keys or
press the numeric key 
.  This menu dictates the
operating mode of the SDU5500:
SPECT = Spectrum display
STRES = Step Resolution
CHANL = Channel scope mode
Section 5-2 
						

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The default is spectrum analyser “SPECT”, if this is not already selected push  SPECT.
The LCD legend “OP.MODE : SPECT” confirms selection.
5)  Go to menu 4, if necessary use the  PREV   NEXT  keys or press the numeric key 
.  This menu
is used to input the centre frequency, define span width and sample rate.
Push the  CF  key and enter the required centre
frequency in MHz format.  In this example select 95
MHz followed by 
.  The LCD legend “CF :
95.00000MHz” confirms entry.
Push the  SPAN  key and enter the widest span
width of 10000kHz (10 MHz) using kHz format
      
Leave the RBW set to 30 kHz. (Ensure that the
SDU5500 gain control is set to “High”, menu 2).
The LCD should be displaying a centre frequency of 95 MHz with a spread of 5 MHz on either side
(the screen representing 90 MHz to 100 MHz from left to right).  Active signals will populate the LCD.
The “CF” and “Marker” frequencies are currently the same and the “CF” is what the companion radio is
tuned to... what you are listening to.
Section 5-2 
						

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Rotate the spin wheel dial to move the marker onto
any active trace, the frequency may be read directly
in MHz format next to the legend “Marker” and the
signal level will be displayed alongside in dBm.
If the incoming signal is greater than -40dBm,
switch-on the companion radio’s attenuator (in the
case of the AR5000 this is via menu 2).
Additional facilities are provided by menu 5 and
menu 6, these include  MK-CF  where the marker
is moved to centre frequency so that activity traces
may be monitored by a single key press.
& Note:  In spectrum analyser mode, the
minimum displayed frequency will be the lower
limit plus one LCD-step, in the above example
 with a centre frequency of 95 MHz, 10000 kHz
span and 30 kHz RBW this will be 90.03290 MHz
with the top frequency being 100.00000 MHz.
5-3  Step resolution mode
In ‘step resolution mode’, ONLY the wanted steps are checked for activity rather than the whole band,
this is particularly useful when you know the tuning steps used on a particular band and don’t want to
view in-between the channel allocations.  To achieve this, the LCD-step is automatically forced to equal
the tuning step of the companion radio.  You cannot manually set the SPAN, by necessity it has to be
calculated by the SDU5500.
As an example of usage, monitor the FM broadcast band using step resolution mode
with the AR5000.
1)  Connect the AR5000 with the SDU5500 referring
to the section 4-1 of this operating manual.  First
switch on the AR5000 then the SDU5500.  Unless
the AR5000/SDU5500 combination has been
previously configured, the SDU5500 will default to
“Other” companion radio.
2)  Go to menu 1, use the  PREV   NEXT  keys or
press the numeric key 
.  Push the  RX  key to
access the companion radio configuration menu.
Section 5-2, 5-3