AOR AR-2700 Wideband Reciever Operating Manual

							AR2700 operating manual
31
ignored.  This is useful for tuning through bands with unusual modes and
channel steps.
To reinstate PROGRAM step size, the receive MODE must be returned to
“PROG” using the “MODE SET” input sequence which is accessed by
pressing [2ndF] [3].
6-7  Changing receive mode (PROGRAM)
As mentioned earlier (section 6-6 of this manual), the specification for step and
mode are allocated by departments of  Government following International
discussions.  Like step size, the receive mode has been pre-programmed at
the factory to simplify operation of the receiver while you familiarise yourself
with all the facilities.
The defaults may be manually overridden at any time should you wish to select
an alternative receive mode on any frequency.
To change the receive mode press [2ndF] [3].
The modes may be accessed in order:
“PROG  WFM FM AM”, “PROG” refers to
PROGRAM MODE.  When “PROG” is
selected, the receive mode and step size
will be selected automatically using the
pre-programmed AR2700 bandplan data
and FM is in fact NFM (narrow FM).
The currently selected mode will be
flashing on the LCD to indicate that a new
mode input is anticipated.  Use the UP / DOWN keys or  [DIAL] to make a
selection, to complete the process press [ENT].  Should you decide not to
change the mode setting, press [CLR].
Note: PROGRAM-STEP and PROGRAM-MODE are linked to the
pre-programmed bandplan data.  When one of the parameters is changed
from the default “AUTO” then the bandplan will be ignored.  This is useful for
tuning through bands in unusual modes and channel steps.
To reinstate PROGRAM step size, the receive MODE must be returned to
“PROG” using the “MODE SET” input sequence which is accessed by
pressing [2ndF] [3].
Any receive mode may be selected at any
frequency within the receiver’s frequency
coverage.  Generally speaking the
following modes will apply:
AM
Amplitude Modulation - Used by broadcast
services throughout the world on medium
wave and shortwave.  AM is also used by 
						

							AR2700 operating manual
32
VHF Civil airband, UHF Military airband and some PMR (Private Mobile Radio)
and utility services.
FM (NFM)
Narrow Band Frequency Modulation - this provides high quality communication
for relatively short distance operation.  NFM is the most common mode used
above 30 MHz with the exception of the airbands.  NFM is widely used on the
VHF bands: VHF Marine band, 2m amateur Band (145MHz), 70cm amateur
band (433 MHz), PMR (Private Mobile Radio) and utilities.
In the absence of a signal, the background
white noise may appear quite loud.  For
ease of listening the squelch control
should be rotated clockwise until the
background noise just disappears, this
should be carried out when no signal is
present.  The point where the background
noise is cancelled is known as “threshold
point”.  Do not advance the squelch
control more than necessary or the
receiver will appear to be desensitised and
weaker signals will be missed.
WFM
Wide band Frequency Modulation - used
by VHF and UHF broadcast stations as
excellent audio quality is available due to
the relatively wide frequency bandwidth
employed.  Used only for local services
such as VHF band-2 stereo (received as
mono on the AR2700) and UHF TV sound
channels.
When listening in VERY strong signal locations especially when using an
external aerial, the WFM I.F. amplifier may be overloaded.  This will not
damage the AR2700 but may result in “apparent signal loss”.  Should this be
encountered, use the attenuator to reduce signal strength or swap to the
standard telescopic whip aerial.
6-8  [ATT] Attenuator ON/OFF
The attenuator adds 10dB of signal reduction to the RF input stages of
the AR2700 to reduce the possible effects of signal overloading due to
connection to an external aerial or when the receiver is used in close
proximity to strong transmissions.
The AR2700 has two settings for ATT (attenuator), On and Off.  When the
attenuator is On, the legend “ATT” appears on the top left line of the LCD.
To toggle the attenuator On/Off while in MANUAL mode press [2ndF] [1] the
legend “ATT” confirms selection and incoming signals will be reduced in
strength.  To toggle On/Off again just repeat the sequence [2ndF] [1], the 
						

							AR2700 operating manual
33
legend “ATT” is extinguished when the attenuator is Off.
The selection of attenuator may also be programmed into memory channels
and when defining program search.
 (7)  Memory banks & channels
It is very convenient to store commonly used frequencies into a memory bank
along with mode and attenuator status, this saves having to key the data in
over and over again.  Memory recall is very straight forward and quick when
compared to retyping all data.
Think of memory channels as pages in a notebook each of which is numbered
to identify it.  Data may be written to each new page (memory channel) and
each page may be overwritten with new data, they can be used over and over
again.
Each memory channel may hold one frequency, mode, attenuator setting,
and step data.  A total of 500 memory channels are provided which are
divided into 10 banks, each having 50 channels.  The memory banks are
identified by the numbers 0, 1, 2, 3, 4, 5, 6, 7, 8, & 9.
Examples are “000” for the first channel
location in memory bank “0” and “049” for
the last memory channel in memory bank
“0”.
“415” is the location of memory bank “4”
channel “15”.
The data contents of memory and search
banks are held in an EEPROM so that no
backup battery or capacitor is required for
memory retention.
The stored data may be quickly and easily recalled, changed or deleted by
re-entry, memory recall, and memory delete.
During the manufacture and testing of the receiver, various test frequencies are
entered into the receiver’s memory banks so the memory locations are unlikely
to be completely blank.
Note: Where memory banks etc are empty the indication “- - -” is often
displayed.
7-1  Storing receive data into memory - memory input in MANUAL mode
For example, to store the frequency of 88.3 MHz with the attenuator Off into
memory bank “0” location “00” (000) while in MANUAL mode. 
						

							AR2700 operating manual
34
Start by selecting MANUAL mode (the [MANU] key) then key in the frequency
of 88.3 MHz, “mode and step size” are set to the default of PROGRAM.
[MANU] to place the receiver into MANUAL mode
[8] [8] [MHz] [3] [ENT] to select the desired frequency, the
mode and step size will be automatically set by the AR2700
microprocessor.
Press and hold the [ENT] key for more than 1.5 seconds to enter
memory input mode.
The legend “BANK” and “CH” will appear
on the LCD and start to flash to indicate
that memory write is in progress.  The first
available empty memory bank and
channel number will be displayed along
with an alternating “- - - -” legend and
frequency to show that no data is currently
stored in the memory location.
To select BANK 0 CHANNEL 00 type
[0] [0] [0] alternatively the UP / DOWN keys will allow selection of BANK and
the [DIAL] will allow selection of channel number.  If data is already stored in
location “000”, the existing frequency will be alternatively displayed along with
the new frequency to be stored... this is a warning just in case you are about to
overwrite important memory data.
There is no need to first delete the
contents of the memory channel, they may
be simply over-written.  Press [ENT] to
write the new data to memory location
“000”.  The frequency, mode, channel step
and attenuator status will be stored.
Remember, if you take too long
entering data (approximately 30
seconds) the display will revert to its
original condition (MANUAL mode).
At any time you may abort the memory input by pressing the [CLR] key, the
display will return to MANUAL mode.
7-2  Automatic memory incrementation
Once you have written data to a memory channel, the next entry will be
automatically incremented by one channel.  If for example you last stored data
to memory location “000” then the next time you press and hold the [ENT] key
the set will move to memory location “001” unless it already holds data in
which case it will move upward sequentially to the first available empty
memory location. 
						

							AR2700 operating manual
35
If you had previously written memory
data to location “315”, then the
microprocessor will automatically
increment to location “316” or the first
available empty memory channel.  The
microprocessor will always select the
bank number last used unless otherwise
specified.
Should you wish, you may instruct the
microprocessor to “offer” an alternative bank or review the current setting.
While in MANUAL mode use the sequence [2ndF] [SCAN] (the second
function being labelled as BANK.  Use the UP / DOWN keys, [DIAL] or
numeric keypad to select an alternative bank then press [ENT].
As you may 
force a bank / channel location during memory write, the above
facility is not essential but provides a better understanding as to how the
memory system operates.
7-3  Memory recall - Recalling receive data from memory
Once receive frequency and mode data has been stored into a memory
location, its retrieval is quick and simple.
For example to retrieve the frequency of 88.3 MHz which has been pro-
grammed into to memory location “000” during the example in the preceding
section of this manual...
Press [SCAN] to place the receiver into memory recall mode.  The legend
“BANK” and “CH” appears on the top left of the LCD to confirm operation.
The receiver will display a memory channel, mode and frequency.  If the
desired memory channel is not immediately displayed it may be RECALLED by
keying in the required location.
To recall memory channel “000” while in
memory recall mode, type  [0] [0] [0] there
is no need to press [ENT].
The receiver will monitor whatever
memory channel first appeared when you
entered memory recall mode or your new
selection.
Memory channel review / hunt
The UP / DOWN keys and [DIAL] may be used to review, hunt for and select
memory channels.
From MANUAL mode press [SCAN] to enter memory recall mode then use the
UP / DOWN keys or rotate the [DIAL] to select the required memory channel. 
						

							AR2700 operating manual
36
This is a useful tool for reviewing memory contents and hunting for a specific
channel when you forget where you stored it!  Should you know the number of
the required memory channel, the keypad method of memory recall will be
much faster.
7-4  Transfer of memory channel to VFO
Should you wish to tune away from the memory channel and benefit from not
having to re-enter the frequency, mode, attenuator setting, channel and step,
the data may be quickly transferred from memory to VFO for tuning in
MANUAL mode.
To transfer the currently displayed memory channel to VFO simply press
[SCAN].  The transferred frequency may be tuned using the  UP / DOWN keys
or [DIAL], the tuning step will have also been transferred from memory along
with mode.
If you wish to return to the previous MANUAL VFO frequency rather than
transfer memory to VFO press [MANU] instead of [SCAN].
7-5  Memory over-write
There will come a time when you will want to change the contents of your
memory banks.  The easiest way to change the memory channel contents is
simply to key new data over the top.
For example, let’s assume that you wish to
store a new frequency of 92.7 MHz into
memory bank “0” location “00” (000) which
has been previously used to store
88.3 MHz.
Start by selecting MANUAL mode.
[MANU] to place the receiver into MANUAL VFO mode ready for
frequency entry and memory write.
Key in the new frequency of 92.7 MHz
[9] [2] [MHz] [7] [ENT] to select the desired frequency, the mode and
step size will be automatically set by
the AR2700 microprocessor.
Now to select and over-write an existing
memory location.
Press and hold the [ENT] key for
more than 1.5 seconds to enter
memory input mode.  The legends 
						

							AR2700 operating manual
37
“BANK” and “CH” will flash to indicate that memory input is in progress.
Press [0] [0] [0] to select the memory location you wish to over-write
(000), the stored frequency and new frequency data will alternately flash
on the LCD.
Press [ENT] to over-write memory
location “000”.  The data will be
stored and the display will return to
MANUAL mode.
At any time you may abort the memory
input by pressing the [CLR] key, the
display will return to MANUAL mode.
7-6  [M.DEL] - deleting individual memory channels and banks
The deletion of memory data presumes that you have previously programmed
memory channels which you now wish to delete!  Once you have deleted
memory channel and memory bank data it cannot be restored so follow the key
sequence carefully.
If the sequence [2ndF] [7] is keyed while in memory recall mode or when
stopped on a channel during scan mode, the displayed frequency will be
deleted from the memory bank and the set will move on to the next memory
channel containing data (upward or downward depending upon how
programmed).
For example, to delete memory channel “000” (Bank 0, CHANNEL 00).
Press [SCAN] to enter MEMORY RECALL MODE.  Key in the desired
memory channel which is to be deleted [0] [0] [0].  Key the sequence
[2ndF] [7] to delete memory channel “000”.
The set will remain in memory recall mode and increment to the next channel
which contains data.  To delete the current channel just key [2ndF] [7].  To
return to MANUAL mode press [MANU].
It is only possible DELETE ALL THE MEMORY DATA FROM A SPECIFIC
BANK by first selecting the memory bank (using [2ndF] [SCAN] [DIAL] [ENT])
while in manual mode, switching the receiver Off, then switching the receiver
On again while holding the [7] key.
For example, press [MANU] to place the
receiver in memory recall mode.  Press
[2ndF] [SCAN] then select the desired
memory bank to be deleted using the UP /
DOWN keys, [DIAL] or numeric keypad.
To accept the selection press [ENT].  Now
power the set Off by pressing and
holding the [PWR] key for more than
1.5 seconds.  Switch the receiver back
On by pressing and holding the [PWR] 
						

							AR2700 operating manual
38
key for more than 1.5 seconds and at the same time holding the [7] key.
Release both keys and the display will remain blank for about 2 or 3 seconds.
The receiver will power up and the selected memory bank data will have been
deleted.   It is also possible to delete ALL programmed data by fully resetting
the microprocessor, this will delete all memory, search, pass data etc.
A FULL MICROPROCESSOR reset is accomplished by holding both the
[CLR] and [ENT] keys while switching On the unit using the [PWR] key.
All memory channels, search banks, pass channels etc will be lost and blank.
As a result the search and scan facilities will not operate until new data has
been entered.  Note: It is quite normal for the set to take about 30 seconds
to recover from a FULL reset as all data has to be deleted !!!
(8)  Priority operation
The PRIORITY feature enables you to carry on scanning, searching or
monitoring while the AR2700 checks a special frequency every five seconds
(default) for activity.
The priority checking is accomplished by
momentarily moving to the priority
frequency to see if it is “active”.  If activity
is found, the receiver remains on the
frequency until the signal disappears.  If
no activity is detected, the receiver returns
to the VFO frequency, scan channel or
search bank from where it originated.
The priority facility has a large number of
applications and is particularly useful for keeping an eye on a distress
frequency while scanning or searching another frequency band.
Note: Depending upon the frequency and mode stored as priority, an
audible “click” may be heard when the priority facility is in operation.
This is quite normal and is caused by the internal switching of circuitry
necessary to accomplish the frequency change as two frequencies
cannot simultaneously be monitored by the receiver.
The priority mode is automatically suspended during entry of frequencies via
the keypad, this prevents the receiver from changing frequency while you are
busy programming.
8-1  Entering data into the priority channel
The [PRIO] key is used to select the priority frequency, select the sampling
interval and toggle the priority watch On and Off.
The priority frequency is selected in manual mode using the key sequence
[2ndF] [PRIO], this is referred to as PRIORITY SET. 
						

							AR2700 operating manual
39
For example, to set the frequency 145.500 MHz as the priority channel:
First ensure that the receiver is in manual
mode by checking that the legend
“MANUAL” is displayed on the LCD or by
pressing [MANU].
Enter the required frequency [1] [4] [5]
[MHz] [5] [ENT].
Transfer the displayed data to the priority
channel using the key sequence [2ndF]
[PRIO].
8-2  Activating & deactivating priority
To toggle the priority watch On and Off
press [PRIO], a “PRIO” legend appears on
the LCD to confirm that priority is 
active
and the priority frequency will be
periodically checked for activity regardless
of whether the receiver is in MANUAL,
SCAN or SEARCH mode.  The priority
channel will be checked for activity even if
the current frequency being monitored is
active.
The receiver will return to its previous operation 
only when the activity on the
priority channel has cleared and the squelch closed.
8-3  Programming priority sampling interval
The priority sampling interval is defaulted to five seconds.  The programmable
range is 01 to 19 seconds.
The interval time is programmed with the
key sequence [2ndF] [PRIO] with the
[PRIO] key held for more than 1.5
seconds.  The value may be changed in
one second increments by using the
UP / DOWN keys or  [DIAL] or by keying
in a two digit number via the numeric
keypad.  The new value is accepted by
pressing [ENT]. 
						

							AR2700 operating manual
40
(9)  SCAN - scanning memory channels & banks
The AR2700 has a SCAN mode whereby the contents stored in the MEMORY
CHANNELS ARE AUTOMATICALLY RECALLED AND MONITORED very
quickly for activity - scanned.
* It is important that you do not confuse SCAN and SEARCH modes. *SEARCH mode (covered later in this manual) automatically TUNES THE
RECEIVER THROUGH ALL FREQUENCIES between two specified frequency
limits looking for active frequencies.
9-1  Starting to SCAN, considerations...
It is presumed that you have already stored your favourite and commonly used
frequencies into the memory banks (as per section 7 of this manual).
A total of 500 memory channels are provided which are divided into 10 banks,
each having 50 channels.  The memory banks are identified by the numbers
0,1,2,3,4,5,6,7,8 & 9 and channels numbered from 00 to 49.
Keep your memory banks tidy - for best scan speed
In order to achieve the maximum scanning speed, it is advisable to keep all
similar frequencies and modes grouped together within the memory banks.
The greater the frequency change between memory channels,  then the further
the receiver’s VCO (Voltage Controlled Oscillator) has to travel and the slower
the scan rates.  Similarly, when many changes of mode are called for the more
switching has to be accomplished and the scan speed may be reduced.
Memory channel data may be entered in duplicate into several channels.
This will ensure the channel data is scanned more frequently to increase
the chances of activity being detected.
Should a number of different modes and wide range of frequencies be used,
then the SCAN process may be affected by noise or differences in squelch
characteristic on some frequencies and modes.
9-2  SCANNING a memory bank...
For example, to SCAN the contents of memory bank “0” (channels 00-49)
which have been previously stored with memory data.
There are two ways to start scanning:
Firstly
From “MANUAL” or “SEARCH” modes:
Press [SCAN] to enter “MEMORY RECALL” mode then press [SCAN]
again and hold the key for more than 1.5 seconds to initiate the scan