7030Bulletins
             
       AOR (UK) Ltd
         
         Unit 9, Dimple Road Business Centre, Matlock, Derbyshire DE4 3JX, 
      England
      Tel: +44 (0) 1629 581222  Fax: +44 (0) 1629 580070

AR7030 Bulletin Page
      Comments from John Thorpe (designer) regarding measurements
      AR7030 spurii list extracted from SM7030 manual
      Frequency stability from cold
      PLL lock times
      Optional filter fitting instructions
      Computer remote control protocol
      RS232 signal meter reading
      Further PC control comments
      INFRARED control information
      Version 2 infrared hand controller (IR7030-2)
      AR7030 'sluggish' behaviour - infrared remote contamination
      Audio coloration
      Filter Calibration
      Sync AM alignment
      Sync AM modification for improved ambient temperature range
      Sync AM use in crowded band conditions
      AGC output - analogue S-meter
      S-meter calibration viewed from the front panel
      Lack of SSB and Sync AM audio
      Audio output stability
      1st I.F. FETS and clamping diodes
      Replacing the SD5400 first mixer
      IP3 bandpass filter modification around 1.7MHz
      Preamp instability
      TCXO frequency reference alignment
      Possible microprocessor related faults
      Removing the microprocessor
      Click encoder replacement - VOL - < >
      Alps click encoder kit
      Replacement of Alps main tuning encoder 
      Replacement of Bourns optical tuning encoder
      Tuning speed
      Die-cast box excluded from production
      LCD backlight brightness
      Noises and AGC pops
      LCD noise
      AR7030 side rail replacement (top case screws stripped)
      Key bounce
      Spurious 'fast charge' LCD message
      AR7030 backup NiCad 
      AR7030 clock 
      BP123 battery option problems with later serial numbers 
      EEPROM corruption of AGC table 
      Power consumption - standby 
      AR7030 AUX / REMOTE accessory power feed 
      FM7030 option 
      DRM modifications 
      Tape record relay specification 
      Unequal audio through headphones at low volume
      Mute / transmit considerations 
      AR7030 and DRM 
      VLF sensitivity 





AR7030 filter calibration
The following describes the operation of the filter calibration routines in the 
AR7030 which will explain the figures observed.  The Filter calibration system 
in the AR7030 serves three main purposes :-

1) to calibrate the filter centre frequency offsets required for LSB and USB 
operation so that the filters give consistent carrier attenuation and tonal 
quality despite widely varying characteristics.

2) to enable additional or changed filters to be incorporated easily, set up for 
optimum operation and identified and selected by the radio operator.

3) to select the appropriate IF tail filter to match the bandwidth of each user 
selected filter.

The system operates by feeding a variable frequency IF signal through each 
filter in turn and monitoring the filter attenuation using the receiver's AGC 
system. The filter is scanned below and above its nominal centre frequency and 
the points where the signal is reduced by 8dB and 20dB are recorded.

The -8dB point is used, rather than -6dB, because the filter's transition slope 
is steeper at this point and with the rather granular measurement of the AGC 
system this provides a more consistent assessment of the filter's
bandwidth. The receiver software then applies a correction to the measured -8dB 
bandwidth to produce a typical -6db figure and to allow for the effects of the 
IF tail filter, which is outside the AGC measurement loop (see the
AR7030 block diagram).

The corrected -6dB bandwidth is used to select the most appropriate IF tail 
filter bandwidth (4kHz or 10kHz) and to provide the entry in the filter 
bandwidth table for user identification. The Filter table order is set by 
sorting these bandwidth figures into ascending order. Note that the calibration 
routine test the filters in the order in which they are installed
in the circuit board, and the filter numbers displayed are not necessarily the 
same as the numbers shown when filters are selected in the FILTER menu.

The -20dB filter frequencies are used to establish the USB and LSB carrier 
positions for each filter. The filter offsets are internally limited to +/- 3kHz 
because there is little need to apply a full USB or LSB offset to the
widest filters, but filters up to 4kHz bandwidth will be set to eliminate the 
unwanted sideband, with a carrier attenuation of 20dB.

An average frequency between the -20dB points is used as the filter centre 
frequency for CW, DATA, AM and Sync modes. The PBS offset display is based on 
this calculated centre frequency rather than the nominal 455kHz centre
of the filters. This allows for manufacturing tolerances and thermal variations.

Because the calibration system shares many common parts with the PBS system its 
frequency range is similarly limited to +/- 4.2kHz. In practice this is not a 
problem because very accurate calibration is only needed for the narrower 
filters used in SSB modes, and the wider filters, used mainly for AM and NFM, 
will tolerate a few hundred Hertz centre offset without any noticeable effect.

Because of these frequency limitations the maximum -8dB bandwidth that can be 
measured is 8.5kHz, which will report as a -6dB bandwidth of 6.7kHz. Any filters 
that are wider than this will all report the same bandwidth. The standard 9.5kHz 
filter is a special case (which is why it cannot be changed) and it will always 
have a bandwidth of 9.5kHz entered in the filter table.
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AGC output - analogue S-meter 
Several people have expressed a desire to add an external analogue signal meter 
to the AR7030 receiver.  The easiest way is to tap into the AGC line and take a 
single wire to an unused pin on the rear panel AUX socket of the AR7030.  An 
Acrobat PDF technical bulletin on this subject has been generated (34kb) - click 
here.
The AGC output is taken directly from the AGC amp so any loading will pull it 
very slightly.  The signal is then fed through a 100k resistor to the input of 
another op-amp paralleled be a 150k resistor to ground.  So keep the load 
resistance as high as possible but there should be no noticeable difference if 
you load it with 470k (just drop a fixed resistor from the 
AGC line to ground and see if it pulls the s meter reading). 
In June 2002, the AR7030 re-mailer discussed external s-meter and Guy Atkins 
posted an Acrobat PDF file initially generated for the JRC NRD525 commenting 
that it may be adaptable for the AR7030.  The file is available here, we offer 
no warranty or support for the data nor do we hold and copyright or claim to the 
material (429kb) - click here.
It is not cost effective for AOR to develop an external s-meter circuit.
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S-meter calibration viewed from the front panel
The following table gives an idea of s-meter reading against input signal fed to 
the 50 OHM aerial socket of the AR7030.
The input is relatively flat across the frequency range of the receiver.  As 
careful attention is given to the AGC calibration during manufacture of each 
radio, results will be very close from set-to-set, maybe within 3dB or so.
This table was generated using a current production AR7030 at 7.1MHz AM with an 
unmodulated signal feeding the 50 OHM aerial socket with WHIP AMP OFF and PREAMP 
OFF.  The test was carried out using FILTER-3, this is the first filter down 
from the 9.5kHz filter
      S1-113dBm0.50uV
      S3-103dBm1.58uV
      S5-93dBm5.0uV
      S7-83dBm15.8uV
      S9-73dBm50.0uV
      S9+10-63dBm158uV
      S9+20-43dBm1.58mV
      S9+50-23dBm15.8mV

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AR7030 IMPROVEMENT OF INTERMODULATION PERFORMANCE
Under extreme reception conditions we have had a report of some intermodulation 
in the area around 1.8MHz. It has been found that there is a slight tailing off 
of IP3 performance in the lower frequency ranges. This is due to the type of 
components used in the 1.7MHz HPF/LPF area of the set. 
A modification to give flat performance from 500KHz to 30MHz can be easily 
carried out. This involves replacement of several surface mount components with 
conventional types.
To carry out this; Remove the top and bottom case halves (4 & 6 screws 
respectively).
Remove the right hand side rail (5 screws). For ease of access, it is also a 
good idea to remove RL3 taking care not to damage any solder pads. 
Remove surface mount components C22 to 27 and L8 to 11.
These should be replaced with Philips 630 series, 100v Med-K ceramic plate 
capacitors and Siemens B78108-T series axial leaded inductors.
Values are as follows; 
C22 1n8(10%)
C23 1n0 
C24 1n8 
C25 2n2 
C26 3n9
C27 2n2
L8 3.3uH (10%)
L9 3.3u
L10 6.8u
L11 6.8u
Crop the leads as short as possible and solder them to the now vacant pads. The 
inductors can be mounted vertically.
Refit RL3 and the case parts. The top case should be fitted before the bottom 
one and the screws only tightened very slightly in order to avoid stripping the 
threads.

Note that most sets will already be fitted with better specification components. 

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RS232 signal meter reading - additional comments
Several commercial organisations are using the AR7030 for signal monitoring 
purposes and wish to accurately log signal meter level.  The information is 
given in the RS232 PROTOCOL LISTING but the subject is fairly complex.  A 
summary of the required process is given here, the text has been generated by 
John Thorpe in response to a commercial request for more detailed guidance 
(November 2001).
Reading the input signal strength from the AR7030 is not too difficult, but some 
maths is needed to convert the level into dBm.

Each set is calibrated after manufacture and a set of S-meter calibration values 
stored in EEPROM in the receiver. This means that the signal strength readings 
should be quite good and consistent. I think that you should get less
than 2dB change with frequency and maybe 3dB with temperature. Initial 
calibration error should be less than +/- 2dB.

I think the sets that you use have been modified for DRM use have some changes 
in the IF stage. This will require that the sets are re-calibrated if you are to 
get accurate results. The SM7030 service kit has a calibration program (for PC) 
and is available from AOR.

The signal strength is read from the AGC voltage within the 7030 so AGC should 
be switched on and RF Gain set to maximum. To read AGC voltage send opcode 02EH 
(execute routine 14) and the receiver will return a single byte value between 0 
and 255 which is the measured AGC voltage.

The calibration table is stored in EEPROM, so the control software should read 
this when connection to the receiver is established and store the data in an 
array for computing.

Calibration data is 8 bytes long and is stored in Page2 at locations 500 (01F4H) 
to 507 (01FBH). Use the PaGE opcode (052H) then SRH, ADR, ADH to setup the 
address, then 8 RDD opcodes to read the data, as below :-

Opcode Hex Operation

PGE 2 052H Set page 2
SRH 15 03FH H register = 15
ADR 4 044H Set address 00F4H
ADH 1 011H Set address 01F4H
RDD +1 071H Read byte 1 of cal data
RDD +1 071H Read byte 2 of cal data
. . . . . . . . . . . . . . . . . . . 
RDD +1 071H Read byte 8 of cal data

PGE 0 050H Return to page 0 for subsequent control operations

The first byte of calibration data holds the value of the AGC voltage for a 
signal level of -113dBm (S1). Successive bytes hold the incremental values for 
10dB increases in signal level :-

Cal data Typical Value RF signal level

byte 1 64 -113dBm
byte 2 10 -103dBm
byte 3 10 -93dBm
byte 4 12 -83dBm
byte 5 12 -73dBm
byte 6 15 -63dBm
byte 7 30 -43dBm (note 20dB step)
byte 8 20 -23dBm (note 20dB step)

To calculate the signal level, table values should be subtracted from the AGC 
voltage in turn until a negative value would result. This gives the rough level 
from the table position. The accuracy can be improved by proportioning the 
remainder into the next table step. See the following example :-

A read signal strength operation returns a value of 100
Subtract cal byte 1 (64) leaves 36 level > -113dBm
Subtract cal byte 2 (10) leaves 26 level > -103dBm
Subtract cal byte 3 (10) leaves 16 level > -93dBm
Subtract cal byte 4 (12) leaves 4 level > -83dBm
Test cal byte 5 (12) - no subtraction
Fine adjustment value = (remainder) / (cal byte 5) * (level step)
= 4 / 12 * 10 = 3dB
Signal level = -83dBm + 3dB = -80dB

The receiver can operate the RF attenuator automatically if the signal level is 
likely to overload the RF stages. Reading the RFAGC byte (page 0, location 49) 
gives the attenuation in 10dB steps. This value should be read and added to the 
value calculated above. 
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Further discussion has taken place on the subject of PC control with the 
designer, the comments may be of assistance to other operators...
As far as I can tell all of the commands and operations work exactly as 
documented so when the client talks of "the set frequency command doesn't work" 
they are obviously doing something wrong. 

Similarly, I am unable to duplicate the effects that they notice with changing 
audio settings after changing modes. There are some issues with the parameters 
that they are changing which I will address later, but first they must sort out 
the basic communication so that the receiver control is as expected. Further 
issues cannot really be sorted until this is working properly. 

Programming issues...

Since I have no Knowledge of what programming system the client is using these 
are only general comments. The receiver control is in 8-bit binary code so any 
communication must maintain all 8 bits (and not truncate bit 7 as some printer 
outputs do). 

It is also essential that no extra characters are added to the output stream so 
check that the software is not adding carriage returns, line feeds, nulls or 
end-of-file markers to the output. If this might be a problem, monitor the 
computer to receiver communication with a serial line monitor or another 
computer running a simple RS232 reading program. 

There is some sample BASIC code in the "AR-7030 Computer remote control 
protocol" document which gives subroutines that cover the commonly used receiver 
settings. Use this as a starting point for your own routines. The published 
routines have been thoroughly tested and work without problems. 

http://www.aoruk.com/pdf/comp.pdf
http://www.aoruk.com/7030bulletin.htm#7030_rs232_s-meter

With all "buffered" RS232 connections it is possible for the computer and 
receiver to get out of step when using two-way communication. For this reason I 
included some "flush input buffer" routines in the sample code. Using these 
ensures that missed characters or extra characters inserted due to noise or 
disconnection do not disrupt communication between the computer and receiver, 
and a recovery after communications failure can be automatic.

Because the receiver's remote control is by direct access to memory and 
processor it is a very flexible system but is also able to disrupt receiver 
operation if incorrectly used. Only a few bytes of information stored in the 
receiver's memory affect S-meter calibration and AOR (UK) hold records of this 
data for each receiver made so that in the event of corruption it can be 
re-programmed. 

See the note that follows regarding AGC calibration.

All other working memory contents can be set to sensible values by a "Set 
defaults" operation from the front panel. Most, but not all, of the working 
memory is re-established by executing a remote "Reset" command (020h) which can 
be done as a last resort after control failure.

Specific parameter settings...

The client describes the correct operations for setting mode and frequency but 
if, as he states, the set frequency command (021h) does not work then this needs 
to be investigated. This may lead to discovering the cause of other problems 
suffered by the client. 

Note that changing the frequency in this way re-tunes the receiver but does not 
update the display on the front panel. A "Display frequency" command is included 
for this purpose.

To set the receiver main volume, three locations need to be written - 
Pg0,01eh,01fh & 020h. Details are in the protocol document, note the minimum 
value (for zero volume) is 15d. The aux channel level change is as described by 
the client and after writing new values into the RAM will need either a "Set 
audio" command or a "Set all" command to make the change. I can find no reason 
for, nor duplicate, the effect of changing mode altering the aux level so this 
effect also needs investigating - maybe the clients "write to memory" is writing 
too many locations ?

To initialise several receiver parameters I would recommend locking the 
receiver, writing all of the required memory data, sending a "Set all" command 
and then unlocking if required. There is no need to send individual "Set" 
commands after each parameter. 

Unless very special requirements are needed (mainly test, setup and alignment) 
the 3 rxcon locations should not be written. When a "Set all" command is sent 
these will be programmed by the receiver firmware to appropriate values for the 
mode, frequency and filters selected. 

Only the parameters that need changing need to be written, all other values will 
be maintained. The locations that the client needs to program for the parameters 
he lists are as follows:- 
  (all page 0)
  frequency frequ 01ah 01bh 01ch
  mode mode 01dh
  volume af_vol 01eh 01fh 020h (values = 0fh 07h 07h for min volume)
  aux level af_axl 023h 024h
  agc speed agcspd 032h
  squelch sqlval 033h
  filter filter 034h
  IF gain ifgain 018h
  RF gain rfgain 030h (value=01h for no pre-amp)
  message wbuff 059h (max 26 bytes)
If the required parameter values are unknown, I recommend setting the receiver 
as required through the front panel controls and then reading the value of the 
memory locations affected using the "read data" operation. 
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Version 2 infrared hand controller (IR7030-2)
The AR7030 has been supplied with an infrared hand controller since its initial 
launch, the part is referred to as "IR7030" and we still carry original type 
controllers priced at GBP  14.99 plus GBP  2.00 inc VAT postage to a UK 
address (correct at Sept'05).

      click the image for a higher resolution JPEG (440kb)From production toward 
      the end of 2005, we will start to use the V2 IR7030 in new production 
      receivers, it will be referred to as IR7030-2. The replacement unit is 
      slightly larger in overall size but has significantly larger buttons (many 
      customers requested this change). 
      The command code is slightly different for the V2 IR7030 (header address), 
      so the AR7030 CPU version of the receiver has to match the IR7030 in use.
      To keep things simple, the original radio firmware for the IR7030 starts 
      with the number "1" (currently 14A and 18B). 
      Firmware to support the V2 IR7030 starts with a number "2" (currently 20A 
      and 20B).
      There is NO DIFFERENCE in features or performance between firmware 1x and 
      2x.

The approximate start point for the processor change is serial number 103670. 
The change in firmware means that the remote controllers are not interchangeable 
unless matched with the correct CPU / firmware. 
We can also supply V2 infrared remote controllers and new microprocessors 
(20A/20B) to any one who wishes to use the V2 controller on earlier production 
receivers.
  The IR7030-2 is priced at GBP  17.95 inc VAT with P&P in the UK being an 
  additional GBP  2.00 inc VAT. 
It is possible to purchase the IR7030-2 with a V2x CPU as a package, you will 
need to replace the CPU though. We will not accept requests for enhanced "B" 
processors in place of standard "A" processors free of charge!!!
  IR7030-2A 
  IR7030-2 version 2 hand controller with a replacement "A-type" CPU for the 
  AR7030 standard radio (firmware 10A - 14A).  GBP  27.95 inc VAT with P&P in 
  the UK being an additional GBP  3.00 inc VAT. 
  IR7030-2B 
  IR7030-2 version 2 hand controller with a replacement enhanced "B-type" CPU 
  for the AR7030 PLUS or when the NB7030 or FPU7030 is used (firmware 14B - 
  18B), no you can't stick it in your standard AR7030 to get extra features!  
  GBP  27.95 inc VAT with P&P in the UK being an additional GBP  3.00 inc VAT. 

  IR7030-2BFPU 
  IR7030-2 version 2 hand controller with a replacement enhanced CPU AND EPROM 
  to equip the standard AR7030 with 400 memories and alpha-tag comments etc 
  (firmware 1xA will become 20B).  GBP  86.95 inc VAT with P&P in the UK being 
  an additional GBP  3.00 inc VAT. 
NB7030 NOTE:
Any one buying an NB7030 will have to advise us which infrared controller they 
have (version 1 or version 2)!
We will post an amendment to the AR7030 infrared protocol listing in the near 
future.
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AR7030 Bourns to Alps click encoder kit
Those wishing to replace the Bourns click encoder may be interested in a PCB kit 
which is now available priced at  GBP 30.00 plus shipping. The kit comprises a 
PCB fitted with two metal cased Alps click encoders, two new knobs and a fitting 
sheet. Tools and technical skill is required for fitting!
A small Acrobat PDF file (63kB) is available detailing the fitting of the kit - 
click here.
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Tuning speed
The tuning rates are given in the AR7030 operating manual technical 
specification section 2, page 33:
2.655Hz in SSB modes, 10.62Hz in AM & NFM modes). 
The minimum tuning step size is quoted in section 5-3, page 9 as:
Increments as small as 2.655Hz 
Infrared control step size rage is stated in section 5-29, page 12 as:
2.7Hz to 50kHz with auto-repeat if the TUNE key is held for more than half a 
second 
Keypad frequency resolution is stated in section 5-39, page 13 as:
+/- 1.4Hz 
The gaining or loosing of a digit is noted in section 6-4c, page 17:
Note: The receiver stores all of its frequencies in binary steps (the AR7030 
doesnt think in decimal!) and as a result the last digit of the displayed 
frequency may gain or loose 10Hz especially if the TUNE keys are used 
repeatedly.  This is because the step size cannot be stored as an exact number 
of kHz.   
Additional comment added 15 May 2002, particularly in respect of use with very 
narrow filters (125Hz)
The Alps tuning encoder has a quoted output of 100 pulses per revolution.  The 
Bourns part used in the AR7030 Plus has a rate of 128 pulses per revolution.  
There is however more to the tuning than manufacturers quoted specification. 
The encoder has two outputs that are 90 degrees out of phase with each other.  
This results in four changes of state that the AR7030 is able to detect and use 
to increment/decrement the frequency by the minimum step size of 2.655Hz with 
each change of state from the encoder.  This gives a tuning rate per complete 
revolution of the tuning knob in SSB mode of 400 x 2.655Hz (1.062kHz) for the 
Alps encoder, and 512 x 2.655Hz (1.359kHz) for the Bourns encoder.  In reality, 
the lack of precision from the Alps encoder results in missed pulses, and the 
ability to carefully tune an individual pulse is very difficult.  Thus despite 
the slight increase in the number of pulses from the Bourns unit per revolution, 
precision tuning is still much easier.  Tuning individual increments does 
however require a fairly steady hand and the best way to tune in very small 
increments is to use the up down keys of the remote control with the step size 
suitably set.
There are other Bourns encoders in the same series, but their availability in  
the UK is limited.  There is a unit that offers 100ppr (little or no UK 
availability) and another that offers 64ppr.  Whilst the latter seems appealing 
to those seeking the ultimate in precision tuning, the gains are sill relative.
To put the whole issue into perspective, for the various types of encoder, 
assuming each produces a good pulse stream, an encoder producing 100ppr equates 
to a rotation of 0.9degrees per minimum tuning increment of 2.655Hz.  An encoder 
producing 128ppr produces a rotation of 0.7 degrees per minimum increment.  
Should the 64ppr encoder be used, it would still only result in 1.4 degrees of 
rotation for each minimum increment.
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AR7030 die-cast box excluded from production
The larger of the die cast boxes is indeed absent from the current production of 
the AR7030 (beginning with serial number 102050). The decision to omit the box 
was taken because of the stress it places on the PCB, particularly around Q47. 
We have always been aware that the level of emission from the DDS system was 
low, however before deciding to omit the box, extensive testing of the receiver 
was performed to check for the presence of any additional spurious radiation 
that may result.
The test proved interesting in that the absence of the box actually slightly 
reduced noise picked up by the receiver in several cases and produced no 
significant change in the level of the known spurii present in the set.
Subsequent production following the run for which this change was originally 
implemented will actually have the mounting points for the large die cast box 
removed but for first production batch following the change the board still has 
the outline and fixing points present. 
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AR7030 LCD back light
The back light and transistor Q77 'divert' approximately 200mA of current away 
from the main 5V regulator. Q77 does most of the work here so even shorting out 
the back light LEDs only makes a few mA difference. No operation appears to be 
affected by this. To do this simply short BLA and BLC on the joints between the 
main and front boards. This is the solder pads on the underside of the radio 
which connect to the PCB area of the volume control... they are accessible just 
be removing the bottom case half with the letter legends printed on the edge of 
the vertical microprocessor PCB. These terminals could be made open circuit but 
the main regulator would have to dissipate the extra heat produced by the extra 
200mA (which it is capable of doing but shouldn't be necessary).
Alternatively, add a resistor between BLA and BLC to divert some of the current 
from the back light LEDs to enable the display to be lit dimly to allow easy 
reading of the figures. I've found a values around 33ohm suitable. Warning; the 
resistor will be passing the majority of the current here and will need to be 
0.5W or more. It will get quite warm. 
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AR7030 TCXO frequency reference alignment
The AR7030 excellent stability is derived from a TCXO at the heart of the 
receiver. This reference is aligned during manufactured using an oven-stabilised 
reference which in tern is periodically referenced to an on-air reference... 
accuracy is extremely good.
Occasionally AR7030 operators comment on a 10Hz to 20Hz displayed frequency 
error on the higher bands, as this does not affect reception in any way, we 
would strongly advice that the reference is left well alone! However, for your 
information, the following alignment information has been extracted from the 
SM7030 service paperwork:
4.1 Reference Oscillator
The frequency stability and frequency accuracy of the entire set, except for the 
real time clock, is dependant on the Reference Oscillator. It consists of a 
temperature compensated xtal oscillator (TCXO) running at 11.13625MHz and a 
buffer stage Q46. It supplies a reference to the CPU, DDS systems and Het 
multiplier.
4.2 Heterodyne Multiplier
The Heterodyne injection signal is derived from the TCXO and multiplied by Q46 
producing a comb of strong harmonics. The fourth harmonic at 44.545MHz is 
selected by the tank circuit TC2, C64 and L29 and fed into the 2nd Mixer, Q20.
The frequency accuracy of the receiver is dependent on a frequency measurement 
of the local oscillator. The meter used for this measurement should have an 
inherent accuracy better than +/- 0.1ppm, and the adjustment accuracy should be 
better than +/- 30Hz. These limits will ensure that the receiver is accurate to 
+/- 0.5ppm.
ADJUST REFERENCE FREQUENCY
Set AR7030 to 30.00000MHz, AM, PBS 0.0 
Local frequency : 75.00000 MHz at TP7 (adjust Q45 TCXO)
Note: If the frequency error is more than a few kHz then it is possible that the 
local osc PLL is unlocked.
Adjust L50 / L51 for 14.0 to 14.3V on TP5.
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AR7030 Audio coloration

There have been a few reports of audio coloration and the matter has been 
investigated at length. WITHOUT AN AERIAL testing produces the most apparent 
difference when switching between USB/LSB especially when using the 2.1 and 
Collins SSB filters, this does not really effect ultimate sensitivity / 
selectivity, the measurement being less than 1dB.
The TCXO reference and AGC calibration table have been cross-checked against our 
records during realignment and confirm that ageing and alignment are not a 
problem. The degree of coloration does vary between AR7030, some are almost 
perfect in this respect but still they vary with temperature from switch-on. We 
have eliminated the most obvious potential problems such as carrier injection 
point & carrier filter, filter measurement resolution (which is 33 Hz resulting 
in any error less than 16.5 Hz), misalignment of TCXO etc. It is simply a 
characteristic which varies between sets. 
We can advise with confidence that the coloration is purely due to filter 
asymmetry... there are effectively 5 filters forming a cascade in the 45 MHz 
I.F., it doesn't take more than 100 Hz asymmetry in any one filter to cause 
"coloration" of audio. 
As the carrier and main audio always pass through the centre section of filters, 
the recovered audio is always good. The AR7030 has particularly been designed to 
offer good close-in strong signal handling, for this reason the user selectable 
(tight) filter is toward the head of the cascade... this provides high 
performance. However in the absence of a signal, wide band noise plus that 
generated in the receiver's I.F. can pass down the I.F. cascade and on to the 
audio amplifier. 
It only takes 100 Hz or so of asymmetry to generate uneven coloration... this is 
not surprising as no ceramic filter is perfect as different physical attributes 
generate each filter edge. As the audio is inverted between side bands, 
accentuation of high tones on USB would become accentuated low tones on LSB. 
Adjusting the PBS just a touch changes the coloration and the AR7030 has been 
designed to ensure that the PBS is held separately in "each" mode.
The signal path is as follows (total of 5 filters):
  1. Two roofing filters 45M1B
  2. User selectable filter
  3. CFU455G2 tail filter
  4. Final tail filter. CFU455IT (4 kHz) for narrow filter selection, or 
  CFU455G2 for wider filter selection.
When using a narrow SSB or narrow AM filter, changing the CFU455IT made the 
largest improvement in audio coloration, however the exact coloration depends to 
some extent on temperature - for this reason it is impossible to be "spot on" 
all the time!
Swapping the standard SSB filter of fitting to a Collins MF2.5 has no real 
effect, but changing the CFU455IT did, the coloration of both side bands became 
quite similar on our test unit.
The effect must be quantified for a set costing GBP 680 + VAT retail for the 
standard unit... The AR3030 generally is much worse under this test with 
different audio coloration obvious even under real signal ECSS tests and 
different s-meter readings between side bands.
The filters are available as spare parts, current prices are as follows 
(carriage extra):
  CFU455IT - (PCB position X10) XCFU455IT/G58 GBP 1.65 inc VAT 
  CFU455G2 - (PCB position X9) XCFU455G2/F33 GBP 1.74 inc VAT 
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AR7030 PLL lock times

The response time of the AR7030 to an input frequency change varies on the size 
of shift and if it crosses over into another VCO range. The actual lock times 
below have been taken from a random set taken from production.

The first PLL lock time has been taken as the time between a frequency change 
instruction being given from the sets microprocessor and a lock signal being 
received back at the microprocessor. 
The second time given is the time taken to receive full audio output (AGC off) 
for the same input instruction.

       Lock signalAudio signal
      Close frequency change (100KHz) 50ms100mS
      Medium frequency change (1MHz)100ms60ms
      Wide frequency change
      (VCO range end to end) 200ms 140ms
      Wide frequency range 
      (change of VCO range)400ms 200ms

Note: An additional time between an instruction being given at the front panel 
and the micro sending an instruction to the PLL are:-

      Approx' 1ms from a frequency change at the main encoder.
      Approx' 80mS from an instruction from the remote IR hand set.

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AR7030 noises and AGC pops

Two customers have reported 'popping' on MW although I cannot say that we have 
duplicated the effect in the workshop (so remains something of a mystery)... one 
customer was in Sweden and the other in Japan.

The Swedish Customer suggested the following component changes:
      Change C104 to 3.3uF
      Short R94 with a jumper

The Japanese customer carried out this change and was happy with the result.

You may notice a change when fitting the UPNB7030 too as an additional filter is 
employed on the UPNB7030 for the spike detection of noise, this will change the 
audio properties to some extent, in fact there is a slight drop in audio 
bandwidth (almost unnoticeable in fidelity) but will help quash high 
frequencies, some customers have commented that they prefer the tone.
The volume, treble and bass controls of the AR7030 are digitally selected by the 
audio amplifier, there are no external components employed, all the features are 
provided directly by the audio amplifier IC.  As the device acts digitally, 
there is a finite number of steps employed.  Unlike analogue tuning controls 
which may be infinitely varied, the audio amplifier switches in steps of 1dB 
and 2dB.  Even the resolution of step size is determined by the audio amplifier 
IC and cannot be altered to provide finer resolution.  It is possible to hear 
clicks and similar anomalies in certain areas of tone and volume setting due 
to the IC switching process, this cannot be eliminated.
 In a similar manner, the FILTER switching momentarily changes the input/output 
impedances of the I.F. chain, in addition the carrier insertion oscillator is 
moved to optimise each individual filter.  A click results from this process 
but cannot be removed.  Furthermore, as the user selectable filter is 
unconventionally placed well up the front of the I.F. path (to provide good 
close-in selectivity), the full audio bandwidth is left to propagate down the 
I.F. chain, any stray noise may appear amplified.  The noise when switching 
filters is more pronounced on earlier versions of the CPU firmware, the routines 
employed in the later releaser have been revised to further reduce 'clicks' when 
switching filters.
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AR7030 LCD noise
The current production (from Y2000 onward) AR7030 has the later LCD fitted, this 
is 'RF quieter' than the original LCD (so does not require the earth strap), of 
course, like all displays, it does still produce noise in some parts of the 
spectrum.  When running from an earthed bench supply, virtually all of the noise 
is eliminated. We would certainly recommend adding an RF earth to your listening 
environment, even a connection to a cold water pipe or central heating radiator 
will be a great improvement, an earth spike (tent peg) when truly remote from 
home.  
The earth strap is NOT fitted to the later LCD type during production, the metal 
display holder is painted which makes adding such an earth strap difficult (the 
benefits are not worthwhile, simply add a good RF earth to the radio earth point 
on the rear case).  Out of curiosity, before changing supplier of LCD, we 
applied an additional earth strap to the LCD (by scratching the paint off)... 
the change in noise level was virtually nil. As the metal surround of the later 
LCD is painted, it has not been practical to apply the additional earth strap 
(but the noise level of the later LCD is generally the same as the earlier type 
with strap fitted). 

AR7030 Earth modification to LCD (not applicable to later LCD types)

The LCD on the AR7030 produced a small amount of noise which can be picked up by 
the radio under certain circumstances. This is most noticeable at lower 
frequencies when using the set with an internal battery pack, a telescopic whip 
and no RF earth. All later sets have an extra earthing strap fitted to overcome 
this problem (from serial number 101713).

To retro fit this extra earthing strap, both covers and the front panel will 
have to be removed. 6 bottom panel screws, 4 top case screws and 4 front panel 
screws (2 on front and 2 behind each fitted with 2 spacers).

Once the front PCB is visible, the earth strap replaces the existing one that is 
fitted from the main PCB to the < > encoder. The new strap is now extended to 
earth the LCD surround as well. 

The new strap is made from a piece of brass shim 5mm X 70mm. Shape the metal to 
form a curve at one end (radius; approx 3mm). Add a thin piece of insulation to 
the outside edge of the radius. The curve can now be slid under the LCD 
screening surround without shorting the LCD contacts (the earth strip hooks 
around the inside edge of the display screening can and sits between this and 
the LCD rubber contact pieces). 

Once behind the LCD screening, the rest of the strip can be shaped over the < > 
encoder and bent around the front panel to enable soldering onto the main board 
earthing point.

The final shape and resting place of the strip will be as shown in the diagram. 
The strip should be trapped between the encoder and the front panel when this is 
replaced.

Replace the front panel and case halves.

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AR7030 side rail replacement (top case screws stripped)
Despite a warning in the AR7030 operating manual and fitting sheets to 'not 
over-tighten' the top case screws, several customers have reported problems 
re-securing the top case because the screws / side-rail threads have stripped.  
It helps to fit the top panel BEFORE tightening the bottom case half.  All 
current production of AR7030 uses 'drilled & tapped' longer screws which helps 
longevity.

There are two ways to 'revive' the top case / side rail fitting:

1 - best method:
Drill the side rails with a 3.8mm drill. Tap the holes with a M4 tap.  Fit 
longer screws (M4x12). Ensure the side rail holes are central to the holes in 
top cover. Ensure all drilling swarf is caught and removed from the radio. 

2 - crude method:
We are not too comfortable suggesting this as a method to resurrect stripped 
threads... remove the side rails from the receiver, belt the side rail (using 
blocks of wood to prevent marking) with a hammer to close the grove a bit more !

We can supply new side rails which are pre-drilled & tapped with appropriate top 
panel screws supplied.  The prices as of 09.04.2001 are as follows:
    Pre drilled & tapped side rail GBP  STERLING 10.40 EACH ex-VAT - 2 required 

    Longer top panel screws for new type side rails GBP  STERLING 0.08 EACH 
    ex-VAT - 
    4 required 
Prices are ex-VAT for export from the EEC, the recipient is liable for any 
import duty & taxes upon arrival in their country (although a charge is unlikely 
due to the relatively low cost involved).
Carriage extra... typically GBP  STERLING 7.00 to North America using small 
packet post by air.
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AR7030 key bounce
A number of reports have been received relating to key bounce, especially when 
switching off the receiver (it switches back on again).  This report is related 
mainly to earlier CPU firmware versions.
There is an anti-bounce routine encoded for the keys within the CPU firmware, 
however this did not take account of a potential for simultaneous 'make' and 
'break' bounce.  The later CPU versions were revised in this area, current 
production is immune from such behaviour unless a defective or very worn switch 
is encountered (it is possible to dismantle and repair a switch on occasion as 
they are built of simple leaf mechanisms only).  Side effects of the key-bounce 
included the set switching back on and menus changing on their own volition (AGC 
and filter values changing).  
If you are suffering from key-bounce and have an early CPU version, we are able 
to re-program the CPU to the latest version with just a handling charge applied 
to cover carriage charges.  Please contact us before shipping your original CPU. 
 Note, we will only upgrade the 'A' standard processor to the current 'A' 
version 14A and the features version to the current 'B' version 18B... in other 
words we cannot supply a free upgrade between CPU types.  This service is only 
available by shipping directly to AOR UK as the HEX files have not been 
released.
Information correct at 08 February 2001.
As the AR7030 front keys age, they become dirtier in operation, cleaning them is 
quite easy but needs some careful handling.  Removal of the switch head 
involves squeezing the two plastic clips on either side of the switch (watch out 
that the spring and inner pieces do not get lost).  Locate the contact plate, 
strangely, only one side is ever tarnished, either reverse the plate or clean 
the dirty side with a fibre-brush.  Reassembly is easy but ensure that all parts 
are offered up squarely so they do not get bent in the process.  Of course it is 
possible to replace the switches but only the tops and 'contacts' need 
replacing de-soldering of the switch would otherwise require complete 
dismantling of the control board.
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Spurious 'fast charge' LCD message
The 'fast charge' message can sometimes appear as a spurious message (when you 
do not have the optional internal battery BP123 fitted). 

Occasionally when a power transient is encountered (thunderstorm), the 
microprocessor 'thinks' it has detected an internal battery but of course it 
needs charging as the voltage measures zero Volts !!!  It then attempts to 'fast 
charge' the phantom battery without success.

The 'fast charge' message will remain on the LCD for about 2 hours... just 
switch the receiver OFF but leave it plugged into power. You cannot cancel the 
message or fool it by switching on/off or unplugging or the 2 hour period will 
simply start over again, patience is required.

There is no harmful effect of the message, ignore it unless it keeps cropping up 
all the time.
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AR7030 backup NiCad

A NiCad backup battery is used to maintain the volatile data of the AR7030 (VFO, 
clock etc).  The AGC calibration table and memory channels are held in EEPROM so 
should not be lost even if the NiCad fails.

It appears that after a few years, occasionally the NiCad does not like to be 
left un-powered for periods in excess of a week or so, they have been known to 
'whisker' and fail... similar to computer BIOS support batteries.

The NiCad is 1/3 AA PCB MOUNTING, the voltage is 1.2V (single cell).  Our part 
number is B0001/I15 and is priced at GBP 1.55 plus GBP 2.00 P&P inc VAT, total 
GBP 3.55 (in the UK).

It is possible to pay using credit card by phone or the SSL page of the AOR UK 
web site, for methods of payment etc have a look at: 
http://www.aoruk.com/payment.htm 

Replacement is fairly straight forward, make sure the set is disconnected from 
supply (not just switched off) as the CPU goes into standby mode while still 
powered and you could really corrupt the operating system if it remains powered.

Be careful not to 'fry' the nearby SMD components, otherwise it is possible to 
remove & replace the NiCad from the inside of the radio cabinet without removing 
the front panel (the hole clearance is large enough).

Occasionally it is necessary to PRESET & TEST to clear the data (if its corrupt) 
using the SM7030 service kit software, in this case, we can usually supply the 
AGC calibration data from our files so that you don't need to re-calibrate the 
receiver (e-mail us with your serial number).
Basically use the 7030TEST.EXE DOS program from the SM7030 service kit (it runs 
in a window fine).
      1) Logon / Setup Debug [ENT]
      1) Logon to receiver [ENT]
      2) Preset and test memory [ENT] - warning, enter 1 to continue [1] [ENT]
      0) Return to main menu [ENT]
      5) IF system & s-meter [ENT]
      3) View / edit 's-meter cal values [ENT]
      1) ENT 60 [ENT]
      2) ENT 10 [ENT]
      3) ENT 20 [ENT] 
      ...
      ...
      10)
      [0] [ENT] [0] [ENT] [10] [ENT]
      In the last section above, substitute YOUR cal values for those in the 
      example.

Carry our a filter re-calibration from the radio CONFIG menu and remember to 
enable any options such as ATTENUATOR step (PLUS unit) and NB7030.

Nothing else should be required... but of course your memory locations will be 
completely empty so you will have to 'manually' start filling your memories 
again.
You can download an extract of the software on this link: click here
NOTE IF USING WINDOWS XP:
If you get an error message while carrying out the preset & test, it may be a PC 
compatibility issue rather than a hardware fault with the radio.
  Presetting memory ..........
  Additional EEPROM .........................
  Checking RTC/RAM
  Error in data after 2 bytes.

  Press ENTER to continue.
The error may by "1 byte" or "2 bytes" depending on how many times you have run 
the software.  This is probably a communications failure due to XP on your PC. 
The 7030TEST.EXE software runs under XP but is rather sluggish.

However, the preset & test part of the program fails on most XP machines 
(presumably due to poor timing / synchronisation). The RS232 serial port on XP 
systems is treated as a network device rather than a hardware/BIOS legacy 
device, even booting XP into a DOS window with compatibility setup or pseudo DOS 
SAFE MODE will not help.

If you have an older PC with DOS_5/6 or Windows_3.1x/95/98/ME it will work fine, 
in the UK workshop we use an old 386/16PC laptop running Windows_3.1, a second 
PC is running Windows_ME.
Otherwise make a W98 boot disk and add the 7030TEXT.EXE utility to the floppy 
disk (you may have to delete the README and CD-ROM drivers from the boot dusk 
for the AR7030TEST.EXE utility to fit).

Boot the XP PC from the W98 floppy and select NO CD-ROM support. Ignore any 
messages about 
the hard drive... you may have to temporarily change the BIOS boot sequence to 
enable you to boot 
from the floppy disk.

When booted, type in 7030TEST and hit enter, you should be able to use the 
software okay.

Afterward, remove the floppy and re-boot the PC as normal.

If you really get stuck, we may be able to place a boot disk in the mail to you 
(it can't be e-mailed as the 
files need to be bootable), a small handling charge would apply.
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AR7030 Clock
The AR7030 displayed clock is referenced from a 32.768KHz crystal, X1 which can 
be found on the rear of the front control panel (remove top cover to view).
It is adjustable by trimming capacitor, TC1 next to it. This is adjusted at the 
time of manufacture and shouldnt need any further adjustment.   
As the emphasis within the radio is towards RF performance, the clock function 
is regarded very much as a secondary function and as such does have its 
limitations.  
The clock crystal is a simple device, it doesnt have any temperature 
compensation or other such circuits to improve its accuracy.
The surrounding ambient temperature, length of periods the set is in use and any 
other factors that alter the temperature within the radio will therefore effect 
the accuracy of the clock. The accuracy of the clock, at best, will always be a 
compromise.
 During production, the clock xtal is set up after several days of use with the 
set at maximum operating temperature. The clock is set slightly fast at this 
point as the radio is unlikely to be subjected to such a high average 
temperature in use after this initial soak test period. Even the most intensely 
used set is likely to be switched off for at least a few hours a day.  The clock 
should therefore keep reasonable time in a set used perhaps a couple of hours a 
day and kept at room temperature when not in use.
Ideally the clock should be set up in the users environment at its average 
temperature. Clearly this is not possible.
During set up, the actual clock period is counted rather than the crystal 
frequency measured. This is not practical in for most people without the use of 
expensive test equipment, so at best, a frequency counter could be used (taking 
care not to pull the frequency). Alternatively, TC1 could be adjusted by trial 
and error monitoring the clock over a fixed period of time.
Warning  TC1 requires very delicate adjustment. The chances are that, after 
adjustment, the clock will be a lot less accurate than before adjustment! 
Proceed with care.           
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BP123 battery option problems with later serial numbers
In the last year two years (2000/2002), we have received a few reports of 
problems with power-up / power-down (LCD behaving strangely) after the BP123 
battery option has been fitted.  Only later serial numbers have produced this 
problem, we assume it is due to component tolerances as there has been no change 
to key components or production methods.  
The 'text' from the bulletin is presented below, the Acrobat PDF file provides a 
simple location drawing for the component position and repeat of text:
      We have had one report (now two) of an AR7030 failing to power down from 
      the front panel when using a BP123 battery option. The fault shows various 
      symptoms, when switching the set off, it may switch itself back on again 
      after a couple of seconds or at worst, lock up completely.  This does not 
      occur when the normal power supply is used with the set. 
      The problem appears to be confined to newer sets.  Older sets have no 
      problem regardless of the age of microprocessor fitted.  Newer sets appear 
      to be OK with 12A microprocessors (an unlikely situation) but may display 
      the problem with 14A, 16B and 18B versions.
      The problem appears to be due to the switch off delay (or its decay) time 
      of the 5V line supplying the microprocessor. No changes have taken place 
      with the programmed delay time, so differences must be due to manufacturer 
      changes or tolerance differences within components in later sets. 
      Different micro batch codes may also be a factor.
      The problem can, however, be easily overcome by the addition of a small 
      delay in the supply switching control line. This is done by the addition 
      of a 22uF capacitor between the junction of R231 / D55 to ground.
      R231 is located close to the battery connector, J11, just in front of 
      relay, RL5. Connect a capacitor between the end closest to D55 and any 
      suitable ground.  Click here for the 11kb PDF file
      Revised text March 2002 
      On some later AR7030s, problems may arise when the optional battery pack, 
      BP123 is fitted. The problem shows up with the symptoms that the set 
      powers itself on and off a couple of times or at worse enters this cycle 
      continuously.
      The problem may show in three ways;
        The set is unable to power itself off from the front panel switch under 
        battery operation. 
        This may also occur when power is removed from the rear panel socket 
        with the set switched off. 
        The set may enter the same state if the power switch is pressed for a 
        very short period of time  this isnt normally be a problem and 
        wouldnt be encountered in normal use. 
      In all of the above cases, the set will recover itself by operating the 
      power switch.
      Do not, however, confuse the problem with simply having a flat battery.
      The reason for the problem is not actually a faulty component but is due 
      to changes in component manufacture used during the various production 
      runs of the AR7030. 
      Two simple fixes can be added if the problem is encountered.
      1) The easiest fix (which is detailed above), which will cure most cases, 
      is simply by adding a 22uf or 47uf capacitor between the junction of R231 
      and D55 down to ground.
      2) A more comprehensive modification is effected as follows;
      Cut the +5C supply track at a point around C212 (next to the rear panel, 
      close to the contrast spindle)  this feeds pins 15 & 16 of Q81, 82 & 83.
      Now add a suitable diode bridging the cut track (suitable points to solder 
      are from the supply side of VR4 and to pins 15 & 16 of Q81 - Anode towards 
      VR4). Fit a resistor across the diode  10k should do. Although virtually 
      any diode will do the job, a 1A shottky device has been used purely 
      because it is an easy size to handle and the resultant voltage drop is 
      relatively small. 
      Fit a capacitor from pins 15 & 16, Q81 to ground  a 220uf will do 
      although a 470uf can be fitted to be really sure. A resistor can also be 
      fitted across the capacitor (10k) 
      This can all be done very neatly with the diode and resistor running under 
      the contrast spindle. The spindle just pulls out while working in the 
      area. A suitable earth point for the capacitor can be found next to R84 
      just above X12  this is a feed through hole, so the cap leg can feed 
      through the board and be soldered on the other side if a small amount of 
      resist is moved from the underside of the board.  

Remember, to switch the AR7030 on/off using battery, the power switch must be 
held for a second or two, not just quickly tapped.
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EEPROM corruption of AGC table
It is possible for the AR7030 AGC table (signal meter calibration) to become 
corrupt if power is removed from the radio while under computer control.  It is 
important that the PC control software is terminated and the radio switched off 
from its front panel switch (do not just pull out the power connector or remove 
supply).  Potentially power transients / brownouts could cause similar problems, 
but this is speculative. 
If the table cannot be read by the microprocessor or does not exist, the radio 
automatically loads DEFAULT DATA so that the receiver at least has a change at 
operating normally  However, if the table exists but is corrupt, it is possible 
that the radio will behave strangely (incorrect signal meter or the attenuator 
switching inappropriately). 
It is possible to re-enter the correct AGC calibration data using the SM7030 
service kit (7030TEST.EXE) software which operates on a PC in DOS mode (it will 
run in a window under MS-Windows). 
It is possible to download a ZIPPED file comprising of a PDF bulletin on the 
subject along with the EXE program and supporting documentation.  Please note, 
the content is subject to copyright (c) AOR LTD 2002 and must not be copied or 
published for any reason other than for addressing the issues outlined here.  By 
downloading and / or using the file, it is assumed in law that you accept this 
condition, the software carries no warranty.  click here (120 kb).
If you are using WindowsXP, take a look at the comments in the NiCad battery 
bulletin - click here
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Power consumption - standby
For critical applications, a few customers have requested power consumption 
figures for operation from the a.c. mains power supply (via power invertors) and 
when running from d.c.
Operation via the a.c. supply
Current drawn from a.c. mains via the AOR standard PSU (230V version used for 
this test):

      With a standard AR7030 connected and switched to standby mode48mA @ 230V 
      a.c.
      With an AR7030 PLUS connected and switched to standby mode49.5mA @ 230V 
      a.c.
      Power supply only with no radio connected46.5mA @ 230V a.c.
      Power supply with an AR7030 in normal operationapprox 70 to 80mA @ 230V 
      a.c.


Operation via a d.c. connection
Current drawn from a 15V d.c. power supply:
      With a standard AR7030 connected and switched to standby mode28.2mA @ 15V 
      d.c.
      With an AR7030 PLUS connected and switched to standby mode48.9mA @ 15V 
d.c.

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AR7030 'sluggish' behaviour - infrared remote contamination
The two items from the subject heading are not identical but are loosely 
connected.
Sluggish behaviour of AR7030
A few reports have been been received suggesting that the AR7030 occasionally 
behaves in a very sluggish manner where button presses and tuning appears to act 
in slow motion with little or no response possible from the infrared remote.  
Luckily we have experienced this characteristic with other consumer products so 
the solution was not difficult to find.
The AR7030 has two infrared remote sensors, one on the front cabinet and one on 
the rear.  Under certain situations, it is possible for the infrared sensor to 
become 'saturated' by energy of a similar waveband, this includes the morning 
(red) sunrise at low angles, the setting sun (red) at low angles and low energy 
RF energised fluorescent lights.
If this presents a problem at certain times of the year / light levels, mask the 
infrared sensor which is facing the light source with a piece of black tape or 
relocate the radio or lamp.
The swamping of infrared causes the AR7030 microprocessor to work overtime 
trying to decode the infrared signals (which it can never do because they are 
not true infrared codes).  This results in the AR7030 responding very slowly to 
other inputs.
Contaminated infrared control hand unit
Recently we received a report (Dec'01) of the AR7030 hand unit not functioning 
correctly, it was sending the same AM/Sync signal regardless of which button was 
pressed.  We suspected that the infrared control had become contaminated 
(someone once dropped one in hot sweet tea - it needed a really good clean 
afterward to restore operation).
Following careful cleaning (carried out by the customer following our 
instructions below - as the unit was out of warranty), normal operation was 
restored to the hand unit, the customer was very happy again.  The text of the 
e-mail is presented below as it may be of assistance to others.  The hand unit 
is relatively inexpensive as a spare part:
  To-date, we have only experienced one similar report. On that occasion, the 
  remote control was 'contaminated' internally causing the keys to operate on 
  their own... the customer purchased a new remote and everything was fine.

  As an experiment in the workshop, if the AM/Sync key is held down, all 
  following keys caused the AM/Sync signal to be transmitted again. This remote 
  sends ONE BURST of signal when the key is pressed then stops sending. If there 
  is no external sign of the key being permanently depressed, consider internal 
  investigation.  On the basis of 'you have nothing to lose'... you may wish to 
  open the remote control and examine the keypad membrane (its not easy to gain 
  access).

  1. Remove the battery cover.

  2. Remove the batteries.

  3. The front / back of the cabinet is held together with lugs, there are two 
  in the bottom, two in the top, one on each side plus numerous smaller lugs.

  Stand the remote on its bottom edge so that the battery compartment is next to 
  the desk top with the front printed letters 'AOR' facing upward and away from 
  you. In the very bottom (below the bottom battery), there are two access 
  points which can be used to prise the rear cabinet from the front cabinet. 
  Generally work around the rest of the cabinet until it is completely apart 
  using a TWISTING action... you will note that the top IR window stops the top 
  cabinet halves from easily separating.

  4. The PCB is held in place by two small lugs on each side-edge. Remove the 
  PCB to access the keypad membrane.

  5. Look for any signs of contamination on the membrane and PCB. We once 
  recovered an IR control after it had been for a swim in hot sweet tea!

  6. While the PCB may be cleaned with isopropyl-alcohol, do not use any 
  chemical to clean the membrane as it is simply carbon printed. If it is 
  contaminated with a liquid, simply clean with water for a very brief period.

  7. Partially reassemble the keypad and PCB so that contact is made with the 
  battery connections. Re-fit the batteries and test. If all is working, 
  re-build the remote and re-test.

  We cannot totally discard the possibility of a fault with the radio itself, 
  but this is very unlikely and would be the very first instance of such a 
  failure. It would be great if you could test the radio with another AR7030 IR 
  or check your IR on another AR7030.

  snip
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AR7030 AUX / REMOTE accessory power feed
The AR7030 has 14V available on the rear panel AUX and REMOTE connectors (refer 
to the AR7030 operating manuals for exact pin-out information).
Both outputs are fed from the same internal supply line via a fuseable 22 OHM 
0.5W resistor (R237), so the total current via the resistor is limited to 100mA, 
not 100mA per connector.

The fuseable resistor is not self resetting, if damage, it will need to be 
replaced.  The resistor is intended to prevent serious damage to the radio in 
the event that the accessory supply is shorted (low voltage directive, part of 
the CE approval).
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FM7030 - VHF stereo FM option
The AR7030 has been designed with a stereo signal path to the front panel 
headphone output and rear panel AUX socket, this was 'designed-in' to allow the 
later fitting of an optional Band-II FM receiver board. Initially there had been 
considerable interest expressed in such an extended coverage board, especially 
in the USA with the Drake SW8 being an example.

The Band-II receive board was intended to address a niche market providing high 
sensitivity and selectivity with RDS ident display offering the Band-II DX'er 
"real performance" instead of using standard Hi-Fi tuners or wide band 
receivers.

Shortly after release however, interest in such a receive board almost 
completely dried up, particularly when considering projected price against 
development cost and the potential small market.

We have been careful not to "promise" the FM7030 option and unfortunately it has 
proven uneconomic to develop - so will sadly not appear.
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DRM (digital AM) modifications
The AR7030 can be modified for reception of DRM signals when used in conjunction 
with a PC for demodulation.  The modifications have been developed by The 
Fraunhofer Institute in Germany and permission has been given for AOR to employ 
the modifications in the AOR AR7030 receiver.
Currently the Fraunhofer DRM PC software is targeted toward broadcasters, so 
features abound but price is relatively high.  Before the end of 2002, we hope 
to see a streamlined DRM PC package at a much reduced price, maybe cheaper than 
50.  Members of the DRM consortium have indicated that they will be publishing 
DRM modification details when the software is released, AOR UK will be providing 
a modification service for the AR7030, prices and full details to be published 
here at a later data.
May 2002.
For further information regarding DRM, please have a look at the AOR UK DRM 
related pages and visit the DRM consortium site at http://www.drm.org 
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Tape record relay specification
The AR7030 has the ability to provide audio for a tape recorder and DC motor 
switching via the rear panel AUX 8-pin DIN connector.  In particular, pin 6 & 
pin 7 provide independent relay contacts (made when a signal is present and 
squelch is open).  The relay 'contact' specification is 24V DC at 1A maximum.  
The AR7030 is NOT intended to switch a.c. mains supply (100 - 230V).
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Unequal audio through headphones at low volume
The line amplifier is used to drive the front panel headphone socket (not the 
main audio amplifier).  The line amplifier drives left and right channels 
independently and supplies both the front panel headphone socket and rear panel 
AUX socket.  The level to the AUX socket can be configured through the CONFIG 
menu.
When using sensitive headphones, you may notice that the left/right volume level 
becomes unequal at low volume settings.  In fact when the audio is turned off 
completely, one channel may still be just audible.  This is due to a small 
amount of cross-talk within the receiver.  To improve the characteristic, lower 
the volume levels in the config menu to 70% or less (the default is 99%).  This 
is a compromise of design and is not considered a serious issue - but a few 
customers have noted the effect.
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Mute / transmit considerations
Pin-1 on the AR7030 AUX socket must be grounded to mute the AR7030 during 
transmit. The mute line performs two functions:
      1) Mutes the audio (it also stops some of the control functions from 
      operating).
      2) Causes the AGC line to go high, this desensitises the receiver. The 
      signal meter 'freezes' close to its previous reading during mute.

Reservations: 
The AGC isn't applied until relatively late in the receivers signal path. The 
front end (SD5400 mixer) is still open to the full RF signal from the 
transmitters aerial.  Designing a circuit to ground the receivers aerial input 
when transmit occurs would be a better solution (in addition to applying the 
mute control).  Useful points would be...
      a) Mute line, normally 5V shifting to 0V when muted.
      b) Pin-34 of the AR7030 microprocessor, inverse of mute live, 0V, 5V 
      muted. This should be capable of providing the switching level for an 'RF 
      mute' circuit.

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AR7030 DRM
For information regarding use of the AR7030 for DRM please refer to the DRM 
page:
DRM - AR7030
DRM - AR7030 and the BBC
The text presented here has largely been extracted from e-mail communications, 
read it in that context.
There has been growing interest in WIDE DRM bandwidths (20kHz), the following 
text may be of interest...
The DRM modified receiver is designed for operation on 9kHz / 10kHz 
transmissions. If 20kHz DRM signals are to be monitored, the 45MHz IF crystal 
roofing filters would need to be replaced, these are not available in small 
quantities so we cannot offer a 'wide DRM' modification at this time. The 
switchable 455kHz filters and the 455kHz tail filter (fixed for AM purposes) 
would also need to be replaced.

Bandwidths for the standard unmodified AR7030 are as follows;

45MHz IF (45M15) crystal filter pair: +/-7.5kHz (3dB).

Switchable 455khz ceramic filters: 455F +/- 6kHz (6dB) or 455D +/- 10kHz (6dB).

Tail filter 455kHz: 455C +/- 12.5kHz (6dB).

Given the band width of the wider of the switchable filters (ignore the 9.5kHz 
displayed filter, this is actually +/-4.5kHz), the main restriction to band 
width is the 45MHz crystal filter pair and possibly to some extent, the 
switchable 455kHz filter.

If the crystal filters overall 15kHz is not wide enough given the allowed 
degradation at the signal edges, it would be easy to widen the band width with 
the use of 45M20 xtal filter pair to open it up to an overall 20kHz. Similarly, 
the 455D could be replaced with a 455C.

Similarly any of the other filters could be substituted for wider versions if 
required. If DRM performance is the only criteria, then it should be possible to 
tailor it to whatever is required (assuming the filters can be obtained in very 
small quantities).

As the comments presented here is untested, it is very much on a 'try it and 
see' basis.

# # #

Further comment

The AR7030 was originally designed with SW listening in mind. The assumption 
being that people would be concentrating on fitting narrower bandwidths rather 
than wider ones (not that wider ones cause any problems). The set was therefore 
configured with a 2nd IF of five moveable filter positions and one fixed filter. 
The fixed filter being approximately 9.5kHz wide.
The sets software/firmware will always place this fixed filter as the last 
filter and label it as 9.5kHz. So even if it is not the widest filter fitted to 
the set it will always come out as the last filter after a filter calibration 
has been run (i.e. filter no. 6 in your set).

Any other filters fitted will then calibrate and be allocated a filter position 
in ascending bandwidth below the 9.5kHz filter. This will always be the case. 
The five 'moveable' filter positions are allowed to display a value between 0 
and 6.6kHz even if of wider bandwidth than 6.6kHz (filter performance is not 
affected by this even if wider bandwidths are fitted)

So even if a 20kHz filter is fitted in one of the five filter positions, it will 
still only display 6.6kHz and get a filter allocation below the 9.5kHz filter.

Until DRM was introduced, this setup worked really well as no-one ever used 
wider filters and the system overcame problems when fitting unusual 
specification and non AOR filters. It makes the set very versatile for normal SW 
use.

The DRM modification design and component choice was done completely external to 
AOR, by the Fraunhofer Institute in Germany. We simply supply the modification 
as designed and specified by Fraunhofer.

Amongst the component changes, the sets overall bandwidth is opened up by 
replacing the 9.5kHz AM tail filter by a 24kHz wide ( +/- 12kHz ) filter (don't 
confuse this with the 9.5kHz filter mentioned previously). The first IF is fixed 
and limited by a filter pair of 15kHz (+/- 7.5kHz).

The other additional DRM filters added are a 12kHz (+/-6kHz) item and a 20kHz 
(+/-10kHz) item, fitted in two of the five moveable filter positions.

These two filters are already wider than the fixed 9.5kHz filter (F6) but they 
will always be displayed as F4 and F5 and show a 6.6kHz bandwidth.

Incidentally, the unmodified filter F3 is a nominal 6kHz filter and will tend to 
display between 6kHz and 6.6kHz (so in some sets this may also show as 6.6kHz).

In short, although several filters may show the same displayed reading, the set 
will always put them in correct ascending bandwidth with the exception of the 
9.5kHz filter which will always be placed in the highest filter position.

In a DRM modified AR7030, the widest filter position is allocated by the set as 
F5. Here the changeable 2nd IF filter is 20kHz wide, the tail filter is 24kHz 
wide, but the limiting filter is the 1st IF filter pair at 15kHz. Therefore 
altering the changeable IF filter to an even wider one would be pointless 
without considering replacing the 1st IF filter pair.
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VLF sensitivity
It is true that the AR7030 will tune down to 0 MHz, the microprocessor is not 
disabled to prevent such tuning, however when you drop below about 6 kHz, the 
receivers local oscillator becomes audible producing near full scale deflection 
of signal meter.  Reciprocal mixing will increase close to the local oscillator 
but  is so clean (when compared to receivers in the same class and many times 
more expensive), it does allow reception well below 20 kHz.
For the above reason, it is not possible to tune to the receiver below 6 kHz 
with a wide filter, you must also bear in mind the mathematics when considering 
wide filters - a negative frequency below 0 MHz cannot be monitored!
The published specification suggests sensitivity down to 20 kHz of (1.9uV/1.4uV 
preamp off/on). 
Further measurements in the UK workshop of a typical unit (in fact several were 
measured) produced a variation of about 6dB at extreme LF due to component 
variation.  Results for 20 kHz, 15 kHz, 13 kHz and 10 kHz are as follows (preamp 
off, switching the preamp on increases sensitivity very slightly but introduces 
additional noise):
      20 kHz SSB S+N/N-96 dBm 3.5uV preamp off
      15 kHz SSB S+N/N-75 dBm 40uV preamp off 
      13 kHz SSB S+N/N-65 dBm 120uV preamp off 
      10 kHz SSB S+N/N-51 dBm 600uV preamp off

Receiving equipment for dedicated LF reception of atmospheric and ground 
movement (earthquake 174 Hz) requires radically different engineering, however 
the AR7030 should produce very useful results down to about 10 kHz.
If the input transformers were to be replaced with more LF specific designs and 
if you were willing to sacrifice the long wire input and whip amplifier, further 
improvements could be made at LF.  The input capacitors and chokes are all too 
small for LF as well and should be replaced.
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performance specification figures indicated are nominal values of production 
units. There may be some deviation from these values in individual units. 
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