JUMA TRX-2 User manual

JUMA TRX-2 Operating Manual
5B4AIY Firmware Version 1.07m
The TRX-2 is an all-band QRP transceiver utilising a direct digital synthesiser and employing
quadrature phase-shift detection in a direct-conversion arrangement for both transmission and
reception, and capable of USB/LSB and CW modes of operation.
This document describes the operation and setup of this equipment using firmware version
1.07m, software modifications and changes made by Adrian Ryan, 5B4AIY.
It assumes that you have already performed the various hardware setup adjustments covering
receiver AGC threshold setting, optimisation of sideband suppression, transmitter final
amplifier bias current adjustments, amplifier gain compensation and microphone level setting.
Front Panel Controls
Control Description
PWR
This button is used to power-up and power-down the transceiver, as well as several secondary
functions. To power up the transceiver, briefly press the button. The display will illuminate
and a sign-on message will be displayed:
JUMA-TRX2 v1.07m
OH2NLT OH7SV
After a short delay, the current frequency bands in use will be displayed either as:
IARU Freq Bands
or:
USA Freq Bands
Then the main display will be shown.
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To power down the transceiver, press and hold the power button, and a message will be
displayed showing a count-down to zero. At this point the display will clear, the backlighting
will be turned off, and the button can be released.
During the count down period the current user settings are being written to the EEPROM. If
the button is released during the count-down, it will be aborted, and the previous operation
will be resumed.
During normal operation, a brief press of the power button will toggle locking the VFO
frequency. Note that this simply disables the VFO tuning knob, the receiver frequency can
still be changed by pressing either the VFO button or using the Rapid Band Switch feature.
The power button is also used to acknowledge and cancel any alarms. If an alarm cannot be
cancelled, then press and hold the power button for 500 mSec and you will enter the
emergency shutdown mode. Release the button and the transceiver will immediately shut off.
In this mode it will bypass saving the user settings in favour of a rapid power down. For full
details of the alarms, please refer to Annex F.
If the power button is pressed and held whilst powering up, the system setup menu will be
selected. The various operations and settings are fully covered in the System Setup section of
this document. To exit the setup menu without making any changes, press and hold the power
button to power the transceiver down.
CW Speed
This knob controls the speed of the internal keyer, or, can be used as a receiver squelch
setting. The operation of this knob is controlled by a setting in the User Configuration menu,
which is covered in the User Configuration section of this document.
MIC
The microphone/PTT switch is connected to this socket by means of a 3.5mm stereo jack.
The wiring is:
Tip : Microphone/Line input
Ring : PTT switch
Screen : Ground/Shield
The PTT switch requires a dry contact closure to ground, or an open-collector connection
capable of sinking 0.5mA from +5V.
The microphone is normally expected to be an electret, and there is a bias voltage of +5V via
a source resistance of 5.7K. If a dynamic microphone is used, a DC blocking capacitor should
be wired in series with the tip connection. Most dynamic microphones have an impedance of
about 400Ω, for optimum speech quality and low frequency response, a capacitor of at least
2µF should be used. If using an electrolytic capacitor, wire the +ve to the tip of the plug.
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DISPLAY/CONFIG
This multi-function button is normally used to control the transceiver’s display. In the receive
mode the normal display has the S-meter, either as a numeric or graphic indication at the top
left of the screen, followed by the mode indicator, (LSB/USB/CW/Tune), and the receiver’s
filter, Wide (WID), Medium (MID), or Narrow (NAR).
A brief push of the DISPLAY/CONFIG button will over-write the mode and bandwidth with
the PWR display, which is only active during either transmit or tune operations. The next
brief push will display the SWR, again only active during transmit or tune. The third push
will show the current DC input voltage, the next push the transmitter’s final amplifier’s drain
current, also only active in transmit, and finally back to the normal display.
If the button is pressed and held, after a short delay you will be presented with the User
Configuration menu. This is more fully covered in the User Configuration section. To exit
from this menu, press and hold the button until a long beep is heard, then release.
AF GAIN
This is the normal volume control.
MODE
This multi-function button has four functions:
Mode Selection
The primary function is that of selecting the operating mode. A brief push will select in turn
LSB, USB, CW, or the Tune function.
Memory Copy
This function allows you to copy the contents of any active VFO to the User VFO Memory
bank.
To access this function, press and hold the MODE button until you hear a long beep. The
display will alter as shown above. To copy from the active VFO to a memory, rotate the VFO
knob clockwise, the direction arrow will point right, and the right-hand VFO memory
designator will increment. In the example above, the active VFO is A, whose frequency and
mode is displayed on the lower line, and is being copied to VFO memory P.
Copy VFO-A to VFO-P
Copy VFO memory J to active VFOA
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To copy from a VFO memory to the active VFO, turn the VFO knob anti-clockwise, and the
source will decrement until you get to VFOA. The direction arrow will reverse showing that
the direction of the transfer is from the VFO memory to an active VFO. In the example
above, VFO memory J, whose frequency and mode are displayed on the lower line, is being
copied to the active VFO, A.
When the MODE button is released, the copy operation will be completed.
Fast User Configuration Page Select
As there are now 21 configuration pages, this feature allows you to rapidly select the desired
configuration page. For details, see the User Setting Configuration section.
Reset Defaults
If this button is held and then the transceiver powered up, the system defaults can be restored
without the necessity of using the System Setup facility. With the transceiver off, press and
hold the MODE button, and briefly press the power button. Wait until the screen displays the
message asking whether you wish to restore the factory defaults. Release the MODE button.
A momentary push of the MODE button will restore the defaults, a momentary push of the
FILTER button will abort the selection, and return you to normal operation.
RIT
A brief push of this button will toggle the Receiver Incremental Tune On/Off. When on, the
lower right-hand portion of the screen will display the current offset frequency up to a
maximum of ±1kHz, controlled by the RIT knob.
If the Include RIT feature is enabled in the User Setup, then the frequency display will show
the actual receiver frequency including the RIT shift.
A long push of this button will invoke the Rapid Band Selection feature.
Frequency Display Including RIT Offset
Rapid Band Select In Use
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If this is invoked, the top line of the display will show the band to be selected, from 160 – 10
metres. If the current receiver’s frequency is within an amateur band, then the selection will
display this band, and the lower frequency display will show the selected frequency. If the
frequency is not within a recognised amateur band, then the out-of-band indicator will show
on the main display, and the 160m band’s frequency will be shown, as illustrated above.
The frequency displayed can be either a default band-centre, or a user stored frequency. These
user frequencies are in addition to those stored in the 26 VFO memories that are also
available, but whereas the VFO memories can store any frequency, the user frequencies can
only be valid amateur band frequencies relative to the current frequency band setting
corresponding to either IARU Region 1, or the US bands.
To select an amateur band, simply rotate the VFO tuning knob which will cycle you through
all the available bands from 160 through 10 metres. When the RIT button is released, the
selected frequency will be used along with the mode stored.
Note that this rapid band switching facility is disabled in both the Split mode of operation and
if the transmitter is keyed either with the PTT switch or a key. It is also inoperative in the
Service and User Configuration modes.
To save a favourite amateur band frequency, please refer to the FILTER button operation.
FAST/VFAST
This button is used to select the various tuning rates that are available. A brief press will cycle
through the Slow (S) Medium (M) and Fast (F) tuning rates, corresponding to tuning rates of
1Hz, 10Hz, and 100Hz.
A long push will select the Very Fast (V) tuning rate of 10kHz. To exit the Very Fast mode,
briefly press the button, and the default Medium 10Hz tuning rate will be selected.
VFO/A=B
This button selects which VFO will be used, as well as several secondary VFO related
functions.
If the operating mode is set to A/B + Split in the User Configuration setup, then a brief
push of the button will cycle through the VFO-A, VFO-B, and Split modes. In the Split mode
the receive frequency and mode is stored in VFO-A, and the transmit frequency and mode in
VFO-B.
In the Split mode, the rapid band switch and user frequency select/store operations are
inhibited. It is highly inadvisable to change frequencies in this mode for obvious reasons. In
order to do so, select either VFO-A or VFO-B.
To copy the VFO-A frequency to VFO-B, select VFO A, and press and hold the VFO button
until you hear a long beep, and the display will show:
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To copy the VFO-B frequency to VFO-A, first select VFO-B, and press and hold the button,
and a similar display will be shown except that the source will be VFOB, and the destination
will be VFOA.
If the button is pressed and held whilst the Splt is displayed, this is the same as VFO-A to
VFO-B.
If the User Configuration setting is for from 3 to 26 memories, then these can be selected
sequentially by a brief press of the button, or if the button is held, they can be selected by
rotating the VFO tuning knob. The last frequency/mode used for the selected VFO will be set.
Any frequency in the range 0 – 30MHz can be stored in the 26 VFO memories.
FILTER
This button is primarily used to select the receiver bandwidths, but also has a secondary
function of storing user frequencies.
A brief press of the button will cycle you through the Wide, Medium, and Narrow filter
bandwidths. The actual bandwidths employed are adjustable via the User Configuration
Menu.
A long press of the button will store the currently displayed frequency and mode into the user
band memory. There are 9 such memories, one for each amateur band, and they are selected
by the Rapid Band Switch feature assigned as a secondary function of the RIT button.
To use this feature, the User Configuration Band Switch setting has to be set to the User
mode. In this mode, the current frequency can be stored. Note, only frequencies within a
recognised amateur band can be stored. If an attempt is made to store an invalid frequency the
top line of the display will show:
Out Of Band!
Split Mode Copy, VFOA to VFOB
Saving A Frequency To A User Band
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Similarly, if the Band Switch setting is in the Default mode, then the display will show:
Not In User Mode
If the Band Switch setting is in the Locked mode, then the display will show:
User Mem Locked!
A successful storage operation will display the message:
Saved to: nnn
where nnn will be replaced by a band from 160 – 10.
In this manner it is possible for the user to preset favourite frequencies for each amateur band,
and to retrieve them on demand. By selecting the Locked mode, these frequencies can be
protected.
System Calibration & Setup
It is assumed that the initial adjustments and settings have been made.
To enter the System Calibration & Setup menu, turn the transceiver off, and then press and
hold the power button until the message:
JUMA-TRX2 v1.07m
Service Mode
is displayed. To cycle through the various setting screens, briefly press the DISPLAY button.
Set Reference Oscillator Frequency
Default: 180000000Hz
The DDS is fed with the output of the precision crystal oscillator, and in the current models is
a packaged component with an output frequency of nominally 30MHz. The worst-case
tolerance for this oscillator is ±100ppm, which translates to a possible error of ±3kHz at
30MHz, and since this oscillator’s frequency is internally multiplied by 6 in the DDS chip,
this can be as high as ±18kHz at 180MHz.
To correct this, the reference frequency can be set to the frequency resulting from a x6
multiplication of the crystal oscillator’s actual output frequency.
In order to determine the necessary calibration factor, an accurate frequency counter is
essential. If you have access to a counter which has an accuracy of better than at least ±1ppm,
then measure the output frequency of the oscillator using the 10 second timebase, making at
least 10 measurements. Average the results to 2 decimal places and multiply by 6. Round this
figure to 1Hz, and this is the frequency to which the reference oscillator should be adjusted.
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It is also possible to use a less accurate frequency counter if you can tune to a standard
frequency transmission. These are usually maintained to an accuracy of better than 0.1ppm.
For an example of how to use this method, please refer to Annex B.
The range of the input setting is checked, and there is an adjustment range of ±20kHz.
Anything outside of this figure is cause for extreme suspicion regarding the crystal oscillator.
Even adjustment settings of more than ±10kHz would warrant further investigation as the
vast majority of these oscillators have a basic frequency accuracy at room temperature of well
within the stated worst-case figure.
Supply Voltage Calibration Factor
Default: 5300
The microprocessor chip uses an internal 12-bit A-D convertor, and this in turn is referenced
to the +5V logic supply. Assuming that the regulator chip is exactly at +5V, this gives an
incremental digital step size 5mV. This is the basic resolution of the digital meter. Use an
accurate digital multimeter and measure the supply voltage at the transceiver’s input, and
adjust the calibration factor to achieve a display as close as possible to that measured.
The accuracy of the internal measurement system has been enhanced with this version of the
firmware, and the incremental quantisation steps are now such that it should be possible to set
the voltmeter to exactly match your measured value
The range is checked, and values from 4000 – 6000 are acceptable, although values
significantly different (more than ±250) from the default value suggest that the logic voltage
should be checked, and investigated.
RF Amplifier Drain Current
Default: 2400
Using an accurate ammeter, measure the current drawn by the amplifier when supplying 10W
in the Tune mode to a dummy load. The value is usually in the range of approximately 2.0 to
2.5A Note that the ammeter only measures the amplifier’s drain current. Using an accurate
ammeter measure the current drawn in the receive mode, and subtract this value from the total
current drawn in the transmit mode. Adjust the calibration factor to achieve the closest match.
The default value is usually satisfactory. The limits are from 1200 – 3600.
Forward Power Calibration Factor
Default: 3550
Using a dummy load, and an accurate power meter, set the transmitter’s output in the Tune
mode using the CARR control on the main board to a forward power of 10W. Adjust the
calibration factor to achieve the closest match. The limits are from 1500 – 5000.
S-Meter Calibration Factor
Default: 1920
This adjusts the accuracy of the S-Meter display, and requires careful consideration. Early
transceivers had a JFET type SST112 used for the AGC amplifier in position TR4 of the
variable gain amplifier A4-B on the main board. Later transceivers had a substitute device
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type PMBFJ112, and the threshold voltage of this transistor differs from that of the SST112.
This leads to a significant difference in the two calibration settings.
In both cases, the adjustment procedure involves terminating the receiver in a 50Ωdummy
load, rotating R53 fully anticlockwise to achieve maximum gain, and then carefully rotating
clockwise until the audio noise just starts to decrease. This is the AGC threshold.
Using a signal generator inject an S9+40dB signal, 5mV, !33dBm, and adjusting the
calibration factor until either the numeric S-Meter just indicates S9+40dB, or the graphical S-
Meter just fills the horizontal display. Then lower the signal to S9, 50µV, !73dBm and by a
combination of R53 and the calibration factor adjustments try and achieve the best
compromise between full-scale and S9 for the two signal levels.
Since the threshold voltage of the two transistors is significantly different, early transceivers
are likely to have calibration factors close to the default, whilst later units will be in the range
of about 3,500 – 4,000. The limits are from 1,000 – 7,000.
Beep Time
Default: 50mS
This adjustment determines the time of all the audio annunciator signals. Adjust the value to
your preference. The range is checked, and values from 0 – 100mS are allowed. If the value is
set to 0, no audible annunciation will occur.
High SWR Trip Limit
Default: 3.00
This is a new feature as part of the alarm sub-system. If the SWR exceeds the trip limit, an
alarm will be generated and displayed on the main screen. The limit can be set from 1.00 –
5.00. Although a setting of 1.00 may seem odd, it allows you to check that the alarm is
working. Set the limit to 1.00, and exit from the System Calibration menu by saving the
settings.
Connect the transceiver to a dummy load, select Tune, and press the PTT switch. If the alarm
is working, then you should see a blinking message “HIGH SWR” on the top line of the display,
along with a beep. To cancel the alarm, release the PTT switch, and briefly press the PWR
button.
Switch off, and reselect the System Calibration menu again, and reset the SWR Trip to a
suitable value.
Overcurrent Trip
Default: ON
This allows you to enable or disable this alarm. If the alarm is disabled, then the following
page will be skipped, although its settings will be retained, and can be adjusted if the alarm is
enabled.
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Overcurrent Trip (Adjustment)
Default: 2.5A
This is a new feature. Adjust the limit to a suitable value. The default is usually satisfactory.
The value can be set from 1.5A – 3.0A. Temporarily setting the trip to 1.5A allows you to
verify that it is working.
As with the SWR test, save the calibration settings, using a dummy load and the Tune mode,
press the PTT switch. The top line of the display will show the blinking message
“OVERCURRENT”, there will be a beep. Release the PTT switch and briefly press the PWR
button to cancel the alarm. Switch off and reselect the System Calibration menu and reset the
trip to a suitable value.
Note that the current measured is that of the final amplifier. The internal fuse is rated at 3.5A,
and since the transceiver’s logic and display sections can consume up to 400mA, the normal
trip limit of 2.5A represents a conservative safety margin. Under some circumstances,
especially if you are attempting to obtain the maximum power out of the transceiver, then it
may be necessary to set the limit to the maximum permissible, 3.0A. Be aware however that
with the logic and backlighting current as well, this is running very close to the fuse rating.
Overvoltage Trip
Default: ON
This allows you to enable or disable this alarm. If the alarm is disabled, then the following
page will be skipped, although its settings will be retained, and can be adjusted if the alarm is
enabled.
Overvoltage Trip (Adjust)
Default: 14.5V
This is a new feature. Adjust the limit to your preference. The range is from 14.0V – 15.0V.
Undervoltage Trip
Default: ON
This allows you to enable or disable this alarm. If the alarm is disabled, then the following
page will be skipped, although its settings will be retained, and can be adjusted if the alarm is
enabled.
Undervoltage Trip (Adjust)
Default: 11.0V
This is a new feature. Whilst the transceiver will continue to operate down to quite low
voltages, when operating portable from Gell cells most manufacturers recommend
terminating the discharge when the terminal voltage falls to 10.5V.
The transceiver can be set to warn you with a blinking “UNDERVOLTAGE” display and a beep at
any voltage from 10.50V – 11.50V. Note, in addition to this final warning, there is a pre-limit
warning which occurs at a voltage 100mV higher than this setting. This will display the
blinking alarm message: “Low Batt Voltage”, and beep.
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