QRP Labs Ultimate3S User manual

Ultimate3S: QRP Labs Multi-mode QRSS Beacon Kit
PCB Revision 1
1. Int oduction
Thank you for purchasing the QRP Labs third generation “Ultimate3S” ulti-mode QRSS beacon kit. This
kit is capable of automated transmission of a range of weak signal modes that are capable of worldwide
HF propagation using a fraction of a watt of RF output power. The Si5351A synthesiser module permits
accurate, stable operation anywhere on LF/ F/HF/VHF whilst plug-in low-pass-filter modules allow easy
band changing.
Recommended app oach to building the kit: This is a simple design but there are a large number of
features which provide a great deal of flexibility. Read this WHOLE manual and unde stand it! Follow
the construction section to build the kit. Use a receiver connected to your PC, with a slow-signal decoding
program such as Argo. onitor your signal, experiment and understand the various features before
connecting an antenna! Good pe fo mance depends on p ope set up: see the calib ation section.
This assembly manual must be ead in conjunction with the ope ation manual!
The U3S kit supports the following modes:
•QRSS mode (plain on/off keyed slow CW)
•FSK/CW mode (frequency shift keyed slow CW)
•DFCW mode (dual frequency CW, dit's and dah's on different frequencies)
•WSPR and WSPR-15 modes (Weak Signal Propagation Reporter)
•Slow-Hellschreiber (frequency shifted slow Hellschreiber)
•Hellshreiber (full-speed standard Hellschreiber, and half-speed Hellshreiber)
•CW (plain CW) and fast FSK mode
•Transmitter mode (manual keyed, on/off CW or FSK)
•Customisable FSK patterns
•Opera
•PI4
Other features:
•Si5351A synthesiser controlled output frequency (kit included with the U3S)
•Plug-in low pass filter boards (for all LF/ F/HF bands from 2200m to 10m, plus 6m band)
•16-column x 2-row LCD with backlight, and two-button user interface
•User-programmable (callsign, message, speed, FSK, mode, etc.), settings stored in EEPRO
•GPS interface, for locking the frequency, timing and location information
•On-chip generation of WSPR encoded message (no PC required)
•WSPR maidenhead locator can be generated from GPS-derived latitude/longitude
•Selectable “frame” size, for stacked QRSS reception
•Plain CW callsign identifier at selectable interval
•Produces approximately 250mW RF output on 30m (lower output on higher frequency bands)
•Higher output power by fitting additional PA transistors and/or higher PA supply voltage
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The transmitter is designed to be powered with 5V DC. This could come from a mobile phone charger, wall
wart, or even four 1.5V batteries connected in series with a suitable low dropout regulator. However not all
chargers and wall warts are clean enough for powering the microcontroller. Do not use more than 6V: this
may kill the microcontroller; the LCD may not work properly with more than 5V. Best results will be
obtained with a well-regulated and well-smoothed 5V supply.
2

2. Design
The ATmega328 AVR microcontroller (IC1) is pre-programmed with firmware to control the LCD, buttons,
and GPS interface. The Si5351A Synthesiser module kit includes its own on-board 27 Hz crystal
reference oscillator. On/off keying is handled in software by switching on/off the output stage of the
Si5351A synthesiser IC. The Q1 BS170 OSFET is the power amplifier, producing about 250mW from a
5V supply on 30m (power output varies on different bands). Finally standard 7-element low pass filter plug-
in modules remove harmonics of the transmission frequency.
3. Pa ts List
3.1 Resisto s
R1 100K preset potentiometer, for LCD contrast adjustment (code “104”)
R2 No resistor – space is provided on the PCB only for reducing LCD backlight brightness
R3 No resistor – space is provided for a 100K resistor, if you want to do AVR firmware upgrades
R4 No resistor – space is provided for a 220K resistor, for smoother contrast adjustment
R5 4.7K preset potentiometer, for setting the PA bias (code “472”)
R6 4.7K resistor
3.2 Capacito s
C2, 3 22pF (ceramic, marking 22, or 220)
C1, 4, 5, 6 10nF (ceramic, marking 103)
C7 No capacitor – space is provided for future enhancements
3.3 Inducto s
L1 25 turns, FT37-43 core (black)
3.4 Semiconducto s
Q1, 2, 3 BS170 (note: two BS170 are provided in the kit. Only one needs to be installed in the kit.
For use with higher PA supply voltages, more transistors may be added, i.e. Q2 and Q3).
D1 No diode - provided for use with relay-switched LPF board kit
IC1 Pre-programmed ATmega328 microcontroller
Si5351A Synthesiser module, including 27 Hz reference oscillator
3.5 Miscellaneous
Two push buttons, S1 and S2
16-column x 2-row LCD (HD44780-compatible) with blue LED backlight
Printed circuit board, 80 x 37mm size
Wire for winding toroid
Socket for IC1
20 Hz quartz crystal
Two 10-pin female header sockets
Two 4-pin female header sockets
16-pin female header socket
16-pin male header plug
Four 12mm nylon hex PCB spacers
Eight 6mm 3 screws
Relay RL0 – not supplied, provided for use with relay-switched LPF board kit
3

4. Const uction
4.1 Gene al const uction tips
The kit comes as a main board, plug-in Si5351A synthesiser module, and a plug-in low-pass-filter module
for the desired band. The Si5351A synthesise module and low-pass filte module a e sepa ate kits.
The synthesise and one LPF a e included with the U3S. Please efe to the sepa ate inst uctions
fo const ucting these kits.
Parts placement is defined by the silkscreen printed legend on the PCB, so please observe it carefully,
paying particular attention to the correct orientation of the semiconductors.
The PCB is quite small and the parts are close together. You are recommended to use a low wattage iron
with a fine tip, and fine solder e.g. 1mm diameter or less. Take care not to overheat the PCB and risk
damaging it. A well-lit area and magnifying glass are useful. Be careful not to bridge solder across closely
packed connections. Some of the joints are very close to each other. I recommend checking with a DV to
make sure no solder bridges have been created.
Note that components D1, Q2, Q3, R2, R3, R4 and C7 are not required or supplied in the kit (R2 may be
added by the builder if lower LCD backlight brightness is desired). Q2 and Q3 are not supplied, additional
BS170 transistors may be installed here to increase the output power (see below). IC1 (the
microcontroller) has an IC socket, in case in future you wish to change the microcontroller e.g. for a
firmware upgrade for new features, etc., or in case you wish to program it yourself. Sockets are provided
for the synthesiser module and the low-pass-filter module.
4.2 Const uction steps
Please refer to the parts placement diagram below.
Pay special attention to the orientation of the semiconductors. For IC1, the dimple in the PCB silkscreen
must be aligned with the dimple at the top of the IC socket and the IC.
The order of construction is not important. However, a good principle to follow is to install the smaller
components first, so that the larger ones do not prevent easy access. One suggested order of construction
is described below. I recommend following it carefully.
4

1) Solde in the socket fo IC1.
To avoid confusion or mistakes later, align the
dimple at one end of the socket, with the
dimple illustrated on the PCB. The dimple
should be at the end nearest the right-hand
edge of the PCB.
2) Solde in all capacito s and the qua tz
c ystal (note the e is no C7).
Be careful not to mix up the 22pF and 10nF
capacitors. The two 22pF capacitors are the
ones on each side of the crystal.
3) Fit and solde switches S1 and S2
The switches are in a convenient location to
press with your left and right index fingers
when holding the module in your hands, with
the LCD facing you. However, it is certainly
nicer to fit off-board switches as well, on a
front panel (see later “hardware options”
section).
4) Wind and install the to oid
The silkscreen printing on the PCB shows
vertical mounting of the toroid. If you prefer
horizontal mounting, there is enough space for
it. When winding the toroid, remember that
each time the wire goes through the centre of
the toroid counts as one turn. 35cm of wire
should be enough for 25 turns. Trim the ends
of the wire, scrape the enamel off and tin them
with solder. As an alternative to scraping the
enamel off, the wire ends may be held in a hot blob of solder on the iron tip for a few seconds, and
the enamel will bubble away. Check continuity on the board with a DV .
5) Solde the sockets fo the Si5351A
synthesise module and the low-pass-filte
boa d.
Some care needs to be taken with the
alignment, to ensure that there is a good fit
when the plug-in boards are added. One
method is to build the plug-in modules first;
then use the Si5351A and LPF boards
plugged into the sockets. You can then solder
the pins, ensuring correct alignment.
5

6) Fit and solde R1, the p eset potentiomete
that sets the LCD cont ast.
Be careful not to mix up the presets R1 (100K)
and R5 (4.7K)! The code on R1 is “104”.
It is a slightly tight fit but apply pressure
carefully and evenly, and the pins of the
potentiometer will fit into the PCB perfectly.
Adjust this potentiometer to the fully clockwise position initially.
7) Fit and solde R5, the p eset potentiomete
that sets the PA bias.
Fit and solder the fixed 4.7K resistor R6.
NOTE: the photograph incorrectly shows R5
as 100K ("104"). It should be 4.7K (“472”). Be
careful not to mix up R1 and R5!
IMPORTANT: Tu n the t imme potentiomete all the way ANTI-clockwise, BEFORE applying
powe to the U3S boa d. Please see section "PA bias set-up" below.
8) Solde wi e jumpe s as shown in the
photog aph and diag am below, depending
on you equi ements.
Typical jumper connections are shown in the
photograph circled in yellow, and by red lines
on the parts placement diagram below.
Please ead the "Ha dwa e options"
sections below, to decide which jumpe s to
fit.
The wire jumpers can be made from offcuts from the other components e.g. capacitor leads. When
installing these wire jumpers, I find it convenient to install them as a small semicircular arch,
perhaps 5mm high off the board, as pictured. This is so that later, if they need to be removed (for
different hardware options configuration), you can easily cut the links using wire cutters. It is easier
than un-soldering them.
The W0-W1 and W2-W3 jumpers hard-wire the LPF into the circuit. Note that when a relay is fitted
at RL0, you do NOT connect these two jumper wires. The relay is part of another kit, the relay-
switched LPF board, that expands the capability of the U3S kit to sequence through up to 6 different
bands.
If R2 is installed, in order to reduce LCD brightness, then connect A1-A2 instead of A0-A1 (see
”hardware options” section below). You may decide to connect A0-A3 to use the software-
implemented brightness control.
You may also install a jumper at the +PA and +5V connections at the bottom of the picture below, in
order to power the power amplifier (PA) with the 5V supply. You should leave out this jumper if you
intend to run the PA at a higher voltage. See more details in the gHardware options h section  
below.
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The "Heat" connection should be connected to +5V also, if you are using the OCXO version of the
Si5351A module. It provides +5V to the oven heater, using a thick track on the PCB. This avoids
voltage drop on narrow traces. If you are using the non-OCXO version of the Si5351A synthesiser
module, then you do not need to connect the "Heat" connection.
Also pay attention to the jumpers at R3 and R4 on the right-hand side of the diagram. R3 is an
optional resistor, to be fitted to enable in-circuit-programming for those wishing to update their own
firmware and having the necessary equipment.
If you do not fit a 100K esisto fo R3, then you must fit a wi e jumpe he e as shown.
Resistor R4 is an optional resistor, which is in series with the top of the contrast adjustment
potentiometer R1 and +5V. Typically the contrast voltage required is less than 1V and the
adjustment is rather sensitive. If you wish, you can fit a 220K resistor in this position, which will
make the contrast potentiometer less sensitive to adjust.
If you do not fit a 200K esisto fo R4, then you must fit a wi e jumpe he e as shown.
9) Solde in t ansisto Q1.
If you have purchased additional transistors
for Q2 and Q3 to increase the power output, I
still recommend starting with just the basic,
single transistor, 5V PA supply setup. Get
things working basically first, then later install
the additional transistors. Walk before you try
to run!
The transistors are located at the edge of the PCB with their flat side outwards. This is to allow easy
attachment of a heatsink if desired (for higher voltage and hence higher power operation).
10)Install two 16-way connecto s on the main PCB and LCD.
Install two 16-way connectors on the main PCB and LCD. Either way is fine, but my
recommendation for installing the LCD connectors, is to use the female (socket) connector on the
LCD side and the male (plug) on the PCB side.
7

Be su e to solde the socket to the eve se
of the main U3S PCB!! Not the top side! it
is ve y ha d to fix late , if you get this
w ong!
Bolt together the LCD module and the PCB,
with the 16-way connectors in place but not
soldered. Then when you solder them, you will
ensure perfect alignment. Use the eight 6mm 3 screws, and four 12mm nylon hex spacers, to bolt
the PCB to the LCD.
The combined 16-way plug and socket when
mated together, have a height of a little under
12mm. Therefore it is necessary to have a
gap somewhere.
y suggested method is illustrated to the right
here. Closely mate the plug and socket. Leave
the gap between the male header (plug) and the U3S PCB. I have found this method works
successfully.
As you can see in the photo, the remaining pin length poking through to the component side of the
U3S PCB is short. However, the pins are still present in the holes and solder will fill the holes and
connect to the pins.
At this stage, also solder the pins of the 16-way socket to the LCD module.
4.3 Module assembly
First the microcontroller IC1 should be inserted in its socket. Be sure to align the microcontroller chip
correctly. The dimple on the chip must be at the same end as the dimple on the socket, and the dimple on
the silkscreen legend on the PCB.
Next, plug together the three modules as shown in the following photographs.
8

Ensure that the Si5351A synthesiser module is inserted the correct way round as shown in the
photograph. The Low Pass Filter kit module should be plugged in with the “Out” legend aligned next to the
RF Output connector of the main PCB (see photo).
Impo tant! Upon powe -up, you will need to adjust the cont ast potentiomete R1 to view the LCD
p ope ly. Tu n it fully clockwise to sta t with (befo e applying powe ). Then tu n it g adually
anticlockwise until the displayed text looks co ect. The series of photographs below show the display
with a) fully clockwise; b) fully anti-clockwise; c) adjusted perfectly. When adjusted perfectly, you will see
"Diagnostic ode" message on the screen.
When you see "Diagnostic ode" it means all is well
with the processor and the LCD communication.
When you press the left button, diagnostic mode will
be cleared. Then you should see the flash screen. If
the Si5351A module is correctly built and inserted,
the firmware will recognise it. The text in the splash
screen will say "Ultimate3S". The "S" is important, it
signifies that the Si5351A has been correctly
detected.
If you cannot see any text on the screen even after adjusting the contrast setting, you have a problem.
Please refer to the "Troubleshooting" page on the U3S website (see resources section below).
4. Ha dwa e Options
4.1 Explanation of connections
The table to the right details the purpose of
the connection points around the right-
hand and bottom edges of the PCB. The
pin-spacing is 0.1-inches and a suitable
connector could be used if desired. These
are further described in the following
sections.
Note that the cluster of connections at the
left board edge are for fitting the connector
to the relay-switched LPF board kit. They
can be ignored for now.
Connections A0, A1, A2 and A4 allow options concerning the LCD backlight, as described below. Typically
you should connect A0 and A3, this enables the software controlled backlight control.
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Label G oup Desc iption
5V GPS +5V supply to GPS module
Gnd GPS Ground connection to GPS module
RxD GPS Serial data input from GPS module
Pps GPS 1 pulse per second input from GPS module
R Future No connection – for future enhancements
S2 Buttons Optional external button S2, switch to Gnd
Gnd Buttons Ground for optional external buttons
S1 Buttons Optional external button S1, switch to Gnd
Clk2 Signal Clk2 Si5351A output, 3.3V p-p squarewave
Clk1 Signal Clk1 Si5351A output, 3.3V p-p squarewave
Clk0 Signal Clk0 Si5351A output, 3.3V p-p squarewave
Gnd Power Ground connection to Power supply
Heat Power +5V heater for OCXO/Si5351A module option
+5V Power +5V power supply
+PA Power PA power supply – may be connected to +5V
Key Control “Keying” output: high during transmit
Gnd RF Ground for RF output
RF RF RF output

4.2 Connection fo basic ope ation
For the most basic operation of this kit as
QRSS transmitter using 5V supply, it
needs only a power supply and RF output
connection.
To allow use of a higher voltage supply for
the PA, there are separate connections for the PA voltage and +5V supply. To run the transmitter using the
5V supply, be sure to connect a wire between the +5V and PA pins. This is shown by the short red
horizontal line in the diagram (right).
The "Heat" connection is only required if you are using the OCXO version of the Si5351A synthesiser
module. You must connect it to +5V to power the oven heater.
4.3 Alte native button mounting option
You may use an external pair of buttons to control the kit. The
button input signals are available at the edge of the board,
labelled S1 (left button) and S2 (right button). The buttons
should be of the push-to-make variety. The left button should
be connected between the S1 signal and ground; similarly the
right button should be connected between the S2 signal and
ground. Suitable buttons are supplied in the official QRP Labs
U3 Case and accessories kit.
4.4 Optional connection of GPS module
A GPS module may be connected to the kit, to provide
frequency stability, accurate time, and latitude and longitude
which can be converted to aidenhead locator format for
encoding in the WSPR message transmission.
Check that your module is powered from 5V. any modules
specify a 3.3V supply - in this case you will need to provide an
external 3.3V voltage regulator. Where a 3.3V GPS module is
used, the serial data and 1 pulse-per-second (pps) inputs are
not a problem for the 5V microcontroller on the kit PCB - no
voltage level conversion is required. Some GPS modules may
need a pull-up resistor however. QRP Labs supply a suitable
GPS module that is powered from 5V.
In cases where the location information is not required
(modes other than WSPR) or you wish to enter it manually,
the serial data input can be left unconnected. The 1 pps input is enough for the frequency lock function. A
1pps signal could be supplied from a non-GPS source, such as a laboratory frequency standard. Note that
the frequency locking function can only operate if you have selected a wait period between message
transmission (i.e. a non-zero gFrame h parameter).  
See operation instructions for details on how to configure the GPS interface.
10

4.5 Highe powe output
The kit provides around 250mW of output power using a 5V supply and a single BS170 transistor
(depending on the band). The transistor gets warm to the touch. If higher output powers are desired, this
can be achieved by using a higher supply voltage for the
Power Amplifier (PA). The microcontroller must still be run
at a voltage not exceeding its 5.5V rating (5V is
recommended). To facilitate running the PA at higher
voltages to provide more power, the PA supply connection
is a separate pin.
At higher supply voltages and power outputs, the heat
dissipation in the BS170 will increase and its temperature will be higher. Provision is made on the PCB for
two more transistors in parallel with the first. This will slightly increase the power output even at 5V supply,
but more importantly at higher voltages it should share the heat dissipation between the devices.
It may be necessary to fix a heat sink to the transistors if the temperature rise is excessive. The transistors
are located near the edge to the board to allow a heatsink. Experiment is needed in this area, with PA
voltages up to perhaps 12V.
4.6 LCD backlight options
a) Full b ightness: For basic operation connect A0 to A1 using a wire jumper (made from a
capacitor lead offcut, for example). The blue LED backlight of the LCD module will be at full
brightness. This is shown as the Red line (left). In this case, do not fit any resistor at the R2
position.
b) Reduced b ightness: You may find the LED backlight of the LCD module too bright for
your liking, or if you wish to operate from battery power, perhaps you consider that it
consumes too much current. In that case, fit a wire jumper between A1 and A2, and use a
suitable valued resistor at the R2 position: experiment, e.g. starting at 100-ohms. 180-ohms
has been reported to work well. 220-ohms or 270-ohms may also suit your taste.
c) Softwa e va iable b ightness: The U3 firmware contains a "Backlight" configuration
setting which can be set from 0 (backlight OFF) to 9 (maximum brightness). This is achieved
using pulse width modulation. To enable this setting, you must connect A0 to A3 using a wire
jumper (do not fit any resistor at the R2 position).
d) Switched backlight: If you do not wish the LCD module's LED backlight to be on all the time, then
instead of the wire jumper, you could connect wires to an on/off switch. This could be useful for battery
powered operation, to reduce current consumption. For example, you could switch the display on to set up
the kit, then leave it switched off during operation. The official QRP Labs U3 Case and accessories kit
includes a spare switch which could be used for this purpose.
4.7 Si5351A outputs
For possible use in other projects, the connection points labelled Clk0, Clk1 and Clk2 provide direct
connection to the Si5351A module's outputs. They are 50-ohm impedance and provide a 3.3V peak-peak
squarewave. Do not draw excessive loads from these connections.
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4.8 In-ci cuit p og amming of AVR
If you own an AVR programmer, you can make connections to the U3S to allow updating the firmware
without removing the AVR chip.
In this case, you should fit a 100K resistor as R3, not a jumper link. This is shown enclosed in RED on the
right side of the below diagram. The other connections required to your programmer, are ISO, OSI,
SCK and Res (reset), these are indicated in the RED square on the diagram. The connection layout is
designed to fit a 2 x 5-pin header, to match common AVR programmer cables. Before use, you should
check that the connections match your programmer, because there are several standards in use. This
board is designed to be as flexible as possible. In some programmers the Gnd connection between OSI
and Res is “NC” (no connection). These are also suitable for connecting to the U3S.
Notes:
1) Power needs to be applied to the U3S during programming! When you start programming, whatever
the U3S is doing at that moment will be interrupted.
2) Some constructors have reported that if the relay-switched LPF board is fitted, the relays chatter
because the programming lines are shared with relays 3 and 4, and programming errors. If this
happens with YOUR programmer, you need to either remove the relay board during programming,
or cut the wires to relays 3 and 4 and put a DPST switch in, to disconnect them when required.
3) The physical space at the 2 x 5-pin header is limited. You may not be able to fit your 2 x 5-pin
connector. Please check before trying to install it.
4.9 Highe sensitivity cont ast potentiomete adjustment
The contrast voltage required by the LCD is typically under one volt, but the potentiometer R1 is connected
between +5V and Gnd. Therefore most of the available travel of the potentiometer adjustment is
redundant, and the contrast adjustment is rather sensitive. If you wish to improve this, you may fit a 220K
resistor at R4 instead of the wire jumper.
12

5. Calib ation
This section is REALLY I PORTANT! It is very important to realise that by far the hardest part of any
successful QRSS beacon operation, is tuning the oscillator to the correct frequency. For example, most
30m QRSS stations monitor a narrow 100Hz-wide band from 10,140,000 to 10,140,100. If you are much
outside this, the chances are that nobody will see your signal. It is therefore essential either to adjust your
output frequency using an accurately calibrated frequency counter, or an accurately calibrated receiver.
If you are going to use a GPS receiver module to provide a 1pps signal to the kit, no calibration is required:
the kit will self-calibrate from the 1pps signal.
In the case that you will not be using a GPS signal, you need to calibrate the kit by entering the correct
value of the 27 Hz reference oscillator frequency into the “Ref. Frq.” configuration setting.
It is possible that you have an accurate means to measure the 27 Hz reference oscillator frequency itself
by probing the correct point on the Si5351A module. However most kit builders will not have the necessary
equipment, and such a measurement is not easy to make without itself risking disturbing the frequency.
The easiest method is to set the output frequency to something convenient such as 13.500000 Hz, and
measure it. easurement can either be by using an accurately calibrated frequency counter, or by setting
up an accurately calibrated receiver with Argo and monitoring the output signal frequency that way.
Once you have measured the actual output frequency, you can calculate the required correction to the
27 Hz reference frequency and enter it in the “Ref. Frq.” configuration setting. For example, suppose you
set the output frequency to 13.500000 Hz but you actually measure 13.500075. Your output frequency is
75 Hz too high. Since your output frequency setting is 2 times less than the 27 Hz reference oscillator
frequency, this means that the actual reference oscillator value is 150Hz too high. So enter 27,000,150 in
the “Ref. Frq.” setting.
6. PA bias set-up
Initially the bias trimmer potentiometer R5 should be set all the way anti-clockwise. When you have set up
the software to configure your U3S for some transmission, connect a 50-ohm dummy load (two 100-ohm
resistors in parallel is fine, or a 47-ohm resistor is fine too). onitor the power output. As you turn R5
gradually clockwise, the power output will increase. At some point beyond half way, the power output will
peak, and as you continue to turn clockwise, power will decrease. This is too far! Now your BS170 will start
getting hot. aybe very hot. So back-off a little. y recommendation is to set the power output a little
below the peak setting. A little ANTI-clockwise, from the peak power output setting.
7 Resou ces
Please see the kit page http://www.hanssummers.com/ultimate3 for any information on latest updates and
issues.
For troubleshooting please refer to http://www.hanssummers.com/ultimate3/u3trouble
Further references are listed in the Operation manual.
13

8. Ve sion Histo y
0 14-Jan-2015
•First version
1 26-Jan-2015
•Correction to section 2, Design. Removed incorrect reference to DDS module and keying transistor
Q1
2 03-Feb-2015
•Correction to R5 value, the supplied trimmer is 4.7K (not 5K as previously stated)
14