QRPproject Blue Cool Radio User manual

Rev:Nobember 20. 2006
1
The blue cool Radio BCR
© QRPproject Motzener Straße 36-38 12277 Berlin http://www.QRPproject.de Telefon: [phone] e-mail: [e-mail]
Manual written by : FIservice Peter Zenker DL2FI email:[email protected]e

Rev: November 20 2006
2
Welcome to start assembling your BCR - Blue Cool Radio. We divided the
complete kit into functional groups which can be tested individually after
assembling. Please follow the manual while assembling because each group
except the first one need the groups built before to be tested. The follow
up inside a group also is not by chance but follows logical and safety rules.
Besides this rules we tried to make it easier for you by using a graphical
coordinate system. Behind all parts you find the coordinates of the part, in
the placement plans you find the same system as a drawing. Following the
coordinates will make it easy to find the correct place for any part.
The first group to be built ist the voltage regulator section
Group 1 Voltage Regulation
BCR should be powered by a 12 Volt power supply or a package of 10 AA
NiMH cells which also give 12,0 V (Working range is 11 to 15 V). Most
stages in BCR work at stabilzed 8 V. We desided to use 8V to protect a
batterie package against low voltage which may destroy it. The choosen
regulator IC 7808 needs 9,5 V to work properly, a NiMH pack with ten AA
cells never should be used below 9,5 V.
The seperate 5V Regulator generates the supply for the central PIC
Processor which controlls the BCR.
Start at the upper left corner at coordinates A/2
Find IC 6, an 78L05 Integrated Circuit in a TO92 housing. It´s flat side
must be positioned as shown in the drawing. As allways good in RF
technique, do not solder it with
„long legs“, the lower part of the IC
should be not more the 2-3 mm
above the PCB.
[ ] IC6 8L05 TO92 A-2, solder
Tantalum Caps are polarised The PLUS side is marked either with a plus sign
(+) or a bar. Also the longer leg identifies the PLUS side. Most Tantalum
caps look like a drop.
[ ] C90 1uF 35V Tantal A-2
[ ] C91 1uF 35V Tantal A-2
Go ahead at F/5 in the lower right corner. The blocking caps often have a
right angle edge in their legs. Please take the time to rework this with a
long nose plier to make it possible to place them very flat to the PCB. If
they are placed to high above the PCB this will cause failures.
[ ] C87 100nF (104) H-4
+-
Akku 12V,intern
Bu4
12V,extern
Ladebuchse
Si1
C87D16
S2
IC5IC6 C88C89C90C91
+12V+8V+5V
Ein-Aus
100nF
1N5402
1uF1uF 780878LO5 1uF1uF

Rev:Nobember 20. 2006
3
[ ] C88 1uF 35V Tantalperle E-5
[ ] C89 1uF 35V Tantalperle E-5
Attention: The following Diode must be placed the right way. The Kathode
of a Diode is marked by a band. If the Tyoe of the Diode is completely
coded by bands, the thickest one markes the cathode. Place the band
according to the placement plan.
[ ] D16 1N5402 G/H-5
IC5 is a voltage regulator in a TO220 Housing, which can handle about 1
Ampere at the desired Voltafe. It must be screwed directly to the PCB´s
ground plane. Because the metall plate of the IC is Ground, we need no
isolation. The printing of the IC looks to the upper side. Before installing
bend the 3 legs 90 degrees down just behind its body. Use a small
screwdriver to get a soft bent.
Screw the IC to its place before you solder it. However, it shoud lay flat on
the PCB to enable the heat to flow away.
[ ] IC5 7808 TO220 F-5
[ ] S2 Toggle Switch 2xUmupright Typ MS500 G-5
[ ] Si1 Fuse Holder G/H-5
[ ] Bu4 DCBU 2,1-PR DC Jack 2,1mm H-4/5
[ ] Si1 Put a fuse into the holder.
Now recheck all your work to find eventually solder failures. Use an
Ohmmeter to check the resistance between the switch and ground, it must
be in the range of several Kilo Ohm.
Connect a power supply. Best choise is a Laboratory supply with adjustable
current limit. Connect it to Jack BU4. Dont short the BCR Fuse with a wire,
there have been others burning their project, you better should not do so.
If you didn´t see any smoke, you now can test your work.
[ ] Test the 8 Volt stabilized line. A good access point is the solderlug at B/
5 (see picture)
[ ] Now the 5V stabilized. You find a solderlug in B1 for good access.
If both Voltages are stable at 8V and 5V +/- some percent, go ahead to
group 2, the controller section.

Rev: November 20 2006
4
Group 2 Controller Section
This section we call the digital heart of our BCR. All functions of the radio
are controlled by the Common PIC Controller. If the controller is in
function, it gives you some internal tools as an advantage: The controler
side tone enables testing the AF part, and the Controllers RF part gives us a
complete signal Generator to
test the IF section later on.
[ ] R63 not used with green
display
[ ] R54 220R 1Watt D-1
[ ] D15 1N4148 C-1
[ ] R56 1K C-1
[ ] R55 2M2 C/D-1
[ ] R62 6,8K C/D-1
[ ] R61 3,3K C/D-2
[ ] R59 1K C-1/2
[ ] R57 2,7K C-2
[ ] R58 4,7K C-2
[ ] R60 22k C-2
[ ] C86 10nF (103) C-2
[ ] C77 10nF (103) C-2
[ ] Q5 4,0MHz Resonator C-1/2
[ ] C84 1,5uF C/D-2
(This one must be installed
lying, with legs bent down by
90 degrees, otherwise you will have trouble with the display later on.
[ ] C83 1,5uF 63V Folie Also Lying D-1/2
[ ] C85 10nF (103) B-2
[ ] C80 1000pF(102) B-2
[ ] C79 1000pF (102) B-2
[ ] C78 1000pF (102) B-2
[ ] R52 100R A-2
[ ] C76 1000pF (102) B-2
[ ] C81 100nF (104) B-1/2
[ ] R53 100R A/B-1/2
[X] C82 100nF SMD 0805 Bottom
[ ] Bu1 3,5mmStereo Jack A-1/2
The following trimmer
potentiometer must be placed
at the bottom side of the PCB
[ ] P7 5K PIHER PT6 A/B-1
Now solder the socket for the PIC
and the socket for the display.
Carefully think what you are
doing, before you solder them,
especially the big PIC socket is
the hell to desolder if it is wrong.
Look at the PIC socket (PLCC
socket). One of its 4 corners
shows a 45 dgree angle. This corner must be placed into the lower left
corner as can be seen in the picture below. Place the socket on the part side
of the PCB. Again compare the 45 degree corner with the drawing. All pins
must find there way into their holes easily without forcing the socket . If it
is at its place, hold it with your fingers and control at the solder side if all
pins found their way
through the PCB. If this is
ok, firmly press the socket
against the PCB and solder
two pins at diagonal
corners. Recheck if the
socket is placed absolutely
flat on the PCB. If not,
resolder the 2 pinst while
pressing the socket down.
If it is ok, solder carefully
all remaining pins.
Use bright light and a
magnifier to controll if all
pins are soldered properly.
[ ] IC4 Socket PLCC44 B/C-
1/2

Rev:Nobember 20. 2006
5
Now the socket for the display. It helps a lot, if you use the display itself as
a justify tool. Take the display, a 16pin connector male and a 16PIN
connector female plus 4 of the 12mm spacers and the small 2mm Screws.
Do not solder yet.
Place the 16pin female connector into the mainboard.
Plug the 16pin male connector into the female connector
Place the display on the upper pins of the male connector. The ends of the
pins look through the holes of the display. Now mount the 4 spacers at all 4
corners of the display between main board and display. Fasten all 4 screws
while holding the display. 16pin connectors must be as exact as possible in
a 90 degree angle on to the mainboard. If this is ok, solder the pins at the
bottom of the mother board and the display board. The ends of the
connector Pins will just flush with the PCB but this is ok because the boards
are throughplated. Start with the outer pins, check again the right angle. If
ok, solder the remaining pins.
[ ] Disp1 16 PIN male, straight A/B/C-1
[ ] Disp2 16 PIN female straight A/B/C-1
[ ] DiSP3 LCD-Display DEM 16216 SYH-LY
[ ] Remove the Display and put the Display, screws and spacers to a safe
place.
Now the C-Mos Transistors. Remember, they are extremly ESD sensitive. Use
ESD tools or decharge yourself by touching a metal ground plate.
(Drawing = first picture section 2)
[ ] T16 BS170 C/D-2
[ ] T17 BS170 C/D-1 There ar e only a few parts left: :
[ ] L10 33mH radial Choke C-2/3
[ ] P8 10K Potentiometer SMC-10-V
B/C-3
[ ] DG1 Shaft encoder ALPS
A/B-3
To complete the controller section, you
now need the DDS Modul. If you got it ready built and tested from
QRPproject, go ahead to the next page where the connectors are installed.
Otherwise assemble the DDS Module now.
Assembling the DDS Modul:
If you have own expierience in soldering SMT parts, you may start
immediate. If not, I recommend to read something about SMT soldering or
to ask an OM with some expierience.
Start with IC1. Adjust it carefully above the Pads, the Dot mus show to the
Callsign upper left corner. Solder to edge pins, controll the pposition again
and solder the remaining pins.
[ ] IC 1 AD9834
Now the other parts from left to rights:
[ ] C1 100nF 0805 [ ] R1 150R 0805
[ ] C2 100nF 0805 [ ] R3 10R 0805
[ ] R2 10R 0805 [ ] C4 10uF Tantal Gr. B
[ ] C3 10uF Tantal Gr. B [ ] C6 100nF 0805
[ ] C5 100nF 0805 [ ] C9 10nF 0805
[ ] C10 100nF 0805 [ ] R4 6k8 0805
[ ] C7 100nF 0805 [ ] C8 10nF 0805
[ ] R5 220R 0805 [ ] R6 220R 0805
[ ] C11 39pF 0805 [ ] L1 1,8uF 0805
[ ] C12 5,6pF 0805 [ ] C13 68pF 0805
[ ] L2 1uH 0805 [ ] C14 5p6 0805
[ ] C15 39pF 0805 [ ] C16 10nF 0805

Rev: November 20 2006
6
Now turn around the PCB. Here you will install the Clock Oscillator and the
3 connectors.
Solder first the integrated Clock. Take care to place the sharp edge to the
upper right corner as shopwn in the picture.
[ ] Clock oscillator
Now mount the 2x2pin and 1x3 pin male connectors. They are placed at the
side where the clock is and soldered at the side where the DDS is. Adjust
them to a 90 degree angle before soldering.
[ ] ST1 connector 2 Pin male
[ ] ST2 connector 3 Pin male
[ ] ST3 connector 2 Pin male
Starting her,e same prodedure for
both, ready made and self soldered
DDS Modules:
Place the female connectors into their
holes, place the modules into the
connectors, adjust the modul on the
connectors and solder.
[ ] ST1 2 PIN female, 90degrees angle
on Mainboard, solder from solder side.
[ ] ST2 3 PIN same
[ ] ST3 2 PIN same
Now place the PIC processor itself into the socket. Find at first the 45
degree side of the PIC. This side must look to the inner part of the PCB.
Dont force too much power while pressing the PIC into the socket, it must
find its place very smooth.
[ ] IC4 PIC16F877 PLCC + B/C-1/2
[ ] Reinstall the Display
[ ] Install the DDS Module
Check all your work with a magnifier for shorts and unsoldered Pins. If this
is ok, apply 12 Volt and start testing of section 2.
After power on, adjust Contrast Pot P7 (on solder side of the PCB) to make
the signs in the display readable. If so, swith power off an on again.
The display should show it´s initial sequence for a short time: Blue cool
Radio and the Firmware revision e.g. 1.14. After the initial frequency it
should show VFO A and B both at 7030 kHz.
At St3 RF- 0ut you will find the RF output of the DDS. Though the
controller is in receive mode, the generated RF is calculated: Display
frequency plus or minus RF depending on the band. You may control it with
a receiver or a counter if you want so. Because most of you will play with
the controller menue, we go on with the description of the Firmware now.
How to use the DDS_BCR
Press the Shaft encoder short: Change Rate sequential 10Hz, 50 Hz, 1kHz
If you are in „Radio“ mode, 100kHz rate is added. Change of rate is
signalized by a short beep (later on, if the AF is installed) Rate is displayed
by decimal point /resolution of the shown frequency.
Press shaft encoder long (> 1s) The display will switch to MENUE.
By turning the shaft encoder, you scroll through the menue
Menue:
0 break Leave the menue without changing anything
1 VFO A/B Switch between VFO A/B
2 Band 0 80m (only available with built in 80m Option) Switch to 80m by
pressing the shaft encoder. Actual frequency of actual band will be

Rev:Nobember 20. 2006
7
stored.
2 Band 1 40m Switch to 40m by pressing the Shaft encoder. Actual fre-
quency of actual band will be stored.
3 Band 2 30m Switch to 30m by pressing the Shaft encoder. Actual fre-
quency of actual band will be stored.
4 Band 3 20m Switch to 20m by pressing the Shaft encoder. Actual fre-
quency of actual band will be stored.
5 Band 4 17m Switch to 17m by pressing the Shaft encoder. Actual fre-
quency of actual band will be stored.
6 Band 5 Radio Switch to Radio (Braoadcast) by pressing the Shaft enco-
der. Actual frequency of actual band will be stored. In Radio Mode TX is
inhibited and 100kHz steps is added.
7 light on/off Backlight on / off. If you see ON in the display, pressing the
shaft encoder will switch to ON. If you see OFF in the display, pressing
the shaft encoder will switch to OFF
8 light auto Backlight automatic. If ON, any touch of the Dial will switch
the backlight on. Backlight switches to off automatically after 2 s inacti-
vity
9 SETUP start of the SETUP Menu
10 keyer Internal keyer electrinic ON /OFF
11 memory read Reads memory. The PIC stores up to 20 Frequencies (num-
ber 01 to 20, shown in the upper left corner of the display. Each Memory
place stores Bandnumber plus Frequency for VFOA and VFOB. With the
shaft encoder you can choose the memory number, the content of the
memory is shown in the display. Cancel stops the operation. There are
two ways to choose the memory contents:
1. Shortly pressing the shaft encoder (only 1 beep) overtakes the stored
frequencies into VFO A/B and switches to the band.
2. Pressing the Shaft encoder long overtakes the frequencies into the VFO
and starts the SCAN function. During Scan the Controller stops for any
recognized signal for a short time. Touching the CW key or the Shaftenco-
der stops scanning at this frequency. Scan allways goes from A to B so
Frequency A allways must be lower then frequency B. ATTENTION: Use
only logical values, otherwise the controller will „hang up“ . If you run in
such a situation the only way to get out is the „Set Default“ function.
12 memory store Write top Memoryr. Choose the Memory like in Menue 12.
Store the actual VFO and Band information by pressing the Shaft encoder.
Any content in the memory will be overwritten.
13 tune. Switches the transmitter to TUNE. During TUNE power and SWR
are displayed.
14 split 1k DDS switches VFO A to receive only and VFO B to transmit only.
TX VFO starts exactly 1 kHz above the RX frequency. The Shaft encoder
now changes only the TX frequency, RX stays stable
15 split 2k DDS switches VFO A to receive only and VFO B to transmitt
only. TX VFO starts exactly 2 kHz above the RX frequency. The Shaft
encoder now changes only the TX frequency, RX stays stable
16 rit Rit on /off. If ON, Row 1 in the display shows RX frequency, row 2
shows TX frequency, original frequency of row 1 was copied to row 2
while switching. Shaft encoder actuates only the RX, TX stays stable.
Paddle in combination with the Shaftencoder:
SPOT: Press shaft encoder end Dot Paddle at the same time. Sidetone is
activated, rate switched to 10 Hz. With the shaft encoder you can adjust
a received CW signal exactlxy to your sidetone which makes your BCR
transceive.
TUNE Press shaftencoder and Dash paddle at the same time. Controller
switches to „TUNE“ mode
SETUP
Go to Menue, choose Setup.
0 Setup break Ends setup Menue, causes hard reset of the controller.
1 DDS-Takt Here you can adjust the clock oscillator. Valu is shown as Hex
Number. ATTENTION: if you store a complete wrong value here, the DDS
will not work any longer. Pressing the Shaft encoder will cause cursor to
go from left to right. Left side are the coarse bits and right side the fine
bits. Right of the lowest bit you will find left, save, cancel. At start the
DDS generates 6075,000 Khz +/. some Hz depending on the Clock fre-
quency. By variing the Hex Number, you can change the generated Fre-
quency until it is exactly 6075,000 kHz. You do this by comparing it with
a good counter or by zerobeating „Deutsche Welle“ at 6075kHz in a
shortwave Radio ( establish a link between DDS Modul and a radio. Tune
the radio to Deutsche Welle. You will hear the DDS as a tone if it is not
exactly at the same frequency. Now tune the DDS until the tone is zero.
If you got the DDS to the correct frequency, use SAVE at the right side to

Rev: November 20 2006
8
store the calibration factor into memory. From now the DDS will generate
very exactly th echoosen frequency
2 ZF (Hz) Here you can adjust the exact IF. The DDS at starting point
generates the estimated IF of BCR which is a little bit lower the the Xtal
frequency (that´s typical for ladder filters). The frequency is shown in the
display in decimal values. The complete procedure is described in the IF
section of the manual.
3 S-Meter Eich S-Meter calibration Menue
1. : No Antenna, Antenna jack open or Dummyload installed (S0). Hex-
value is shown. Press shaft encoder, menue will jump to point 2
2: Apply 50uV ato the Antenna jack, measured Hexvalue is shown. Press
Shaftencoder and leave th eMenbu by SAVE. The Pic will calculate the S-
Meter curve now and store it into memory.
4 pitch Frequency of the sidetone can be choosen by the CW speed poty.
Last stored value shown in the display. The choosen tone frequency must
be aligned with the BFO Frequency during IF adjustment to be transceive.
6 set default This is the „SOS“ point, if all fails. Set default fills all memo-
ries with logicak values. All adjustments will be lost.
Coose „0 Setup break“ to leave the setup Menue

Rev:Nobember 20. 2006
9
Group 3 AF Section
There are only a few parts in Section 3. It represents the AF Amplifier for
both, the received Signals and the TX-sidetone. The AF Amplifier is designed
to drive standard low impedance stereo headphones. Loudness of the
sidetone can be adjusted independent from receiver loudness by trimmpot
P4.
Start with installation of IC3 because it´s easier to be installed if space
around is free of other parts.
[ ] IC3 LM386 B-3/4
[ ] C4110nF Foile spaced 5mm B-4
[ ] R28 10K upright B-4
[ ] C44 10uF 35V rad. B-4
[ ] C40 100uF 16V rad. B-3/4
[ ] C43 47nF (473) B-3
[ ] C36 220nF Foil spaced 5mm
C-3/4
[ ] R29 4,7R upright B-3
[ ] C42 100uF rad. B-3
[ ] R26 120R upright
C-3
Install fullowing diode
also upright. There is a
convention to place
the cathode (banded
side) to th eupper end.
The body is placed inside the printed
circle in the placement plan.
[ ] D11 1N4148 B/C-2/3
[ ] R27 100K upright B-3
[ ] C37 1uF rad B-2/3
[ X] C38 4,7nF SMD 0805 bottom of
PCB
[ X] C39 4,7nF SMD 0805 bottom of
PCB
[ ] R23 270R upright A/B-3/4
[ ] Bu2 3,5mm Stereo Jack A-2/3
[ ] P3 10K Potentiometer SMC-10-V
B/C-4
[ ] P4 10K PT6 Trimmpoti C-3
Remember ESD safety rules if you
install th etransistor!!
[ ] T8 BS170 B-3
[ ] S1 Toggle Switch 2xUm A-3/4
If you again have checked your Work with a magnifier to find possible shorts
and forgotten solder points, you need a headphone and a key to test this
group. If you use a paddle, it must have a 3,5mm Stereo plug with
following connections: Paddle: Tip = Dot, Ring = Dash, Back = Ground.
Handkey (Pumpkey) : Tip and Ground,don´t connect the ring. Switch power

Rev: November 20 2006
10
on and press the key or the dot paddle. You should here the sidetone.
Adjust the level by P4. Go ahead with section 4.
Baugruppe 4 ZF Verstärker / BFO
The FET amplifier T3 together with the transformer Dr4/C16 acts as coupler
to couple the impedance of the Ladderfilter to the selectiv amplifier T4/T5.
As far as we know, the design of the following cascaded IF Amplifier by
Peter, DK1HE is absolutely unique and new. You will enjoy it´s features after
your BCR is ready built.
Transistors T4/T5 are in terms of DC serial cascaded and use half of the
Voltage (4V) each. The commen collector current is adjusted by R14 to
about 3,5mA which is significant low compared
to two seperate driven singel Amplifier stages.
By T6 easily the current through the complete
chain can be varied and by this, the Gain factor
of T4/T5 that means the gain of the IF amplifier
can be regulated. In Terms of RF the amplifier
works conventional. C20/C21 decouple both
stages. T4 does not work with the low input
impedance T5 but its working resitance is the
resonate circuit L4/C9 which gives us much
higher gain per stage.
Output of T5 is working with the resonate
circuit L5/C24. By damping resistors R13/R18
the total unregulated gain is adjusted to about
70 dB.
The IF signal is inductiv coupled by L5 to the
following product detector T7 and diode D10.
D10 has to do 2 jobs: 1. it is used as AM
Detector if BCR is used in AM with BFO switched
off and 2. it generates the AGC Voltage directle
from the IF without an extra amplifier. The AGC
curve can be adjusted by P5.
D10 generates a negative voltage which is
proportional to to the IF Voltage. The neagtiv
voltage reduces the base current of T6 in
conjunction with the fieldstrength of the
received signal, so the total collector currend
and total gain decrease. 0dBm (220mV) at the antenna can be kept by the
AGC without any distortions. Because D10 is used with a negativ Voltage,
eben very small signals can start the AGC. By its negativ temperatur
coefficient D10 compensates the tempereratur sensible base-emitter
junction of T6. The AGC works stable over a wide temperature range.
CW and SSB denodulation is done by the MOS tetrode T7. To keep the
number of parts low, it is designed as a self oscillating mixer. The BFO
Quatz is oscillating with an offset of 500-900 Hz. Behind the Lowpas R24/
C35 there is an AF signal, which can be handled by the AF amplifier.
ZF-Vorverst.
ZF-Verstärker
ZF-Verst.-Regelung
+8V
AGC-Spannung
0,2-1V
+8V
T3
T4
T5
T6
D10
P5
C11
C14
C15
C16
C17
C18
R8 R9 R10
R11R12
R13
R14
R15
R16
R17
R18
zu CPU
A
A
C19
C20
C21
C22 C23
C24
C25
C26
C27
C28
L4
L5
1
2
3
4
1
23
4
Dr3- 100uH
Dr4- 33uH
Dr5 - 100uH
0,47uF
50k
1N4148
47nF
47nF
150p
18Wdg 6Wdg
6,8nF
470k
270R
BC550
BF199
BF199
47nF
47nF
8k2
12k
47nF
entfällt
150p
3k3
12k
33pF
47nF 47nF
2Wdg
18Wdg
3k9
270R
1k
150pF
47nF
47nF
2k2
BF244A
Baugruppe ZF-Verstärker / BFO
C92
22p
BFO
AM Signal

Rev:Nobember 20. 2006
11
So far the theory of this
new IF Amplifier design,
let´s start to asemble it
now.
Start in the lower right
corner in D5
[ ] C11 150pF (151) D-5
[ ] R8 270R upright D-5
[ ] R9 1K upright C/D-5
[ ] C16 39pF (390 or 39) C-5
[ ] C17 47nF (473) C-5
[ ] C14 47nF (473) C-4/5
[ ] Dr4 33uH SMCC C-5 see picture right!!
[ ] R10 2k2K upright C-5
[ ] Dr3 100uH SMCC C-5
[ ] R11 12K upright C-5
[ ] R12 3,9K upright C-5
[ ] C15 47nF (473) C-5
[ ] C25 47nF (473) B/C-5
[ ] C19 150pF (151) B-5
[ ] R13 3k3 B-5
[ ] R14 270 R upright B/C-5
[ ] C26 0,47uF 35V Tantalum C-4/5
[ ] R15 470K B/C-4
Remember ESD rules while installing the following transistors, they are very
sensitive against electrostatic discharge.
Attention: The suffix in a type is essential, it makes the difference. Never
interchange BF244B and BF244A, they are really different. This rule is true
for all European BF, BC, BD type transistors.
[ ] T4 BF199 C-5
[ ] T3 BF244A C-5
[ ] T6 BC550C B/C-4/5
In the next step you will find the first coil. Because all over the world Radio
Amateurs are telling sad stories how difficult it is to make such coils, i will
describe the „how to make coils „ a little bit broader to show you, that
there is nothing secret nor complicated.
In american kits torroids are preferred. In Germany for long times only
cylindrical and shielded cylindrical coils have been used. Both types have
advantages and disadvantages and that´s the reason that in our designs we
use both types. The main advantage of a Coil you will use in this section is
its low footprint. Compared to a torroid it is allmost a halfe place you need
because it must be tuneable and Torroids can only be tuned if you use an
extra variable cap. In our BCR we use a special type of encapsuled variable
Coils. They are named „Bobin“ coil. The body to put the wire on is made
out of ferrite, you see it in the picture at number 4. We wind the wire on
this form not as a single layer but just „as it comes“ The only essential is,
that the number of turns must be correct. The complete Bobin consists of:
1. Shield cap 2. Holder for the ferrite cap made from plastic,
3. Ferrit cap with an outside thread 4. Bobin Body,
5 socket with 5 Pins.

Rev: November 20 2006
12
To prepare the Bobin take the Body, give
a drop of superglue between the snap in
part middle of the socket and snap the
body to the holder. Give the glue a
chance to dry before you go on with the
coil. In the mean you may install some
further parts of section 4.
[ ] DR5 100uH SMCC B-5
[ ] C20 47nF (473) B-5
[ ] C22 47nF (473) B-5
[ ] R16 12K upright B-5
[ ] R17 8,2K A/B-4/5
[ ] D10 1N4148 A/B-4
[ ] C92 22pF (22j) A/B-4
[ ] C27 6,8nF (682) B-4
[ ] P5 50K PT6 Trimmpot B-4/5
[ ] T5 BF199 B-5
So, the glue should be dry, let´s start with
the coil.
Look at the Coil from the upper side and
hold it above the left picture. 2 Pins at
the left side, 3 pins at the right side.
At both the upper and lower side of the
socket, you will see a notch. This notch is
the way the wire has to go if it crosses
from the Socket Pins to the Bobin Body.
Lets´s start:
Sling one end of the wire as it is (no
solder) 3 times around PIN 1. This 3
turns around the pins schould be directly
below the socket, about 1-2cm Look at the picture left, it shows the Bobin
socket from the bottom side to make clear, how the wire is fastened to the
pin. The Pins are very rough so the wire will hold in place.
Now up through the notch to the Bobin Body and clockwise 18 turns
around the body. You will end with turn number 18 just behind PIN 2, go
down through the notch and wind 3 turns around PIn 2 the same way you
did it at PIN 1. Cut the wire leaving a little tail of abt 1-2 cm again.
Thats all, the Resonate winding is finshed. L4 needs a coupling winding This
consists of 2 turns. Start at PIN 3 again with 3 turns around the pin very
next to the body, go up throuh the gap and wind clockwise 2 times around
the body. You will end at Pin 4. Go down through the notch, 3 times
around PIN 4 and cut the wire you dont need for this coil 1-2 cm behind
the pin. This coil is ready, except it has to be soldered now. The easiest way
to do is to hold it with the PINs upside in a vice to have both hands free.
Clean the tip of your solder iron carefully. Now touch the 3 turns around a
Pin with the solder tip and at the same time with thin solder. Temperature
of the solder iron should be between 350 and 400 dreges Celsius. Wait 1-3
second until the solder flows and remove the iron. The laquer on the wire
normaly momentary is cracked and she copper is tinned to the Pin. After
soldering the 4 pins cut of the wire tails and check your work with an
ohmmeter. Result must be: about zero ohm betwen 1/2 and 3/4.
If this is ok, you can prepare the rest of the coil. Take the blue plastic
holder and the ferrite cap and screw the cap into the blue plastic holder. Do
the first turns without a tool, use your finger. Try to do it without too
much power. The ferrite and the plastic
must be in one axis. Try two turns
forward, one backwart several times.
Doing it this way, you will get a nice
threat into to plastik making later
adjustment of the coil easier. Now place
the coil on its place with the 5 Pins
through the holes in the PCB. Adjust the
coil to stand exact upright and solder the
Pins, do not use to much solder. Carefully
check that no extra solder is to see at
the upper side at the pins which could
cause a short to the shield.
2
1
3
4Bobin
Body
3 Turns just below the socket

Rev:Nobember 20. 2006
13
Place the prepared blue plastic with its ferrite
cap on the the coil. Place the shield can over
the plasitk, The two noses of the shield should
go through their corresponding holes in the
PCB, but do not solder the shield now.
[ ] L4 Neosid 7.1 F10b B-5
Reson. Winding: 18 turns 0,1 mm laquered wire
Coupl. winding: 2 turns 0,1mm laquered wire
Now finish group 4:
[ ] C35 47nF (473) A-4
[ ] C30 82pF (82p or820) A-4
[ ] R24 10K upright A-4
[ ] R22 1K upright A-4
[ ] C31 47nF spaceing 5mm (473) A-4
[ ] C33 47nF (473) A-4
[ ] C28 10pF (10p or100) A/B-4
[ ] R21 150R upright A-4
[ ] R20 100K upright A-4/5
[ ] R19 5,6K upright A-5
[ ] DR10 47uH SMD bottom A-5
[ ] C23 47nF (473) A-5
[ ] C24 150pF (151)
A/B-5
[ ] C29 2,5-60pF Foil variabke cap
7,5mm black A-5
[X] R18 not used
A/B-5
[ ] C32 10uF 35V rad.
A/B-4
[ ] C34 100uF 16V rad.
A/B-4
The Dual Gate MOS T7, BF981 is very
sensitve against ESD remember the ESD rules. The picture left shows the
pinning as you you see it from the upper side, orinting readable. It will be
installed exactly as you see it here. The little Dot in the drawing remarks the
long drain pin. Bent all 4 pins carefulle downwards 90 degrees, and place
the transistor into it´s holes. If all is ok, you still can see the type-print,
otherwise you have bent the pins the wrong direction. Solder all 4 pins from
the solder side (bottom of PCB)
[ ] T7 BF981 Attention, ESD rules!!! A-4
The Quartz must be soldered a little above the PCB to prevent it against
getting shortened by solder at its bottom. Easiest way to to is to use a cut
of from a resistor temporary between the PCB and the quartz. Dont forget
the to remove the cutof after soldering the quartz
.
[ ] Q4 4,915MHz HC49U A-4/5
Next to the Quarz you will see a little rectangular soldered pad. This is to
ground the housing of the quartz. Solder a resistor cutoff to this pad and
solder the other end to the quartz housing at about half the height of the
housing. Soldering at the quartz housing is easier, if you clean the solder
place with a glass hair brush or similar tool.
[ X] C18 47nF SMD0805 bottom C-5
[ X] C21 47nF SMD 0805 bottom B-5
Last thing in this section is coil L5.
Wind 18 turns between pin 1 and 2 as you learned it for L4. The coupling
this time has 6 turns instead of 2. Wind 6 turns between Pin 3 and 4
[ ] L5 Neosid 7.1 F10b A/B-5
Resonate winding: 18 turns 0,1 mm laquered wire
Coupling winding: 6 turns 0,1mm laquered wires
Thats all. The IF Amplifier is ready built and rady to be
tested. Before testing, again check your work with the
help of a magnifier and a bright lamp. All ok?
Connect a Headphone. Connect a piece of wire to point
X as shown in the drawing below. Dont solder, just plug
it into the hole. The other end lay without electrically
contact on the DDS Modul. This will grab some RF from
the DDS output to the IF amplifier. The upper end of the

Rev: November 20 2006
14
Ferrit caps of L4 and L5 should be about 1-2 mm below the copper shield.
Now switch on your BCR. Go to Menu, Setup and into the ZF section. The
default frequency stored by us is 1kHz below the Xtal frequency, that is the
normal value for this type of ladder filters. Because there is no Xtal filter
built in, the absolute frequency is not very important in this moment. In
the headphones you should hear a signal now. The frequency depends on the
trimmer C29. You may have a look at the AGC Voltage: connect a Voltmeter
to the upper end of R14 and ground. Range 0-2 V. Switch off the DDS in the
Menue. Adjust Trimpot P5 to abt 0,2V. Now again switch on the DDS:
Menue, Setup, ZF. The voltage at R14 should increase. You may adjust L4/
L5 now for maximum reading, but the final adjustment will be done later on
after the Ladder filter has been installed.
Switch off your BCR and remove the link wire. Go ahead with section 5
Group 5 DDS Signal preparation,
Mixer, IF buffer and Ladder Filter
[ ] C48 1000pF (102) E-3
[ ] C47 10nF (103) E-3
[ ] R33 1M upright E-2/3
[ ] R36 100R upright E-3
[ ] R34 47k upright E-3
[ ] R35 1K upright E-3
[ ] C49 100nF (104) E-3
Attention, place the notch of the socket to the right side as shown in the
picture .
[ ] DIL 14 socket D/E-3
Dont install the IC now, this will be done if the sectrion has been
completed! [ ] Dr1 100uH SMCC C/D-2/4
[ ] C13 47nF (473) C-4
[ ] Dr2 100uH SMCC C-4
[ ] C3 47nF (473) D-4
[ ] C4 100nF (104) E-4
Take care for the notch!
[ ] DIL 14 socket D/E-3/4, do not
install the IC itself!
[ ] C9 47nF (473) D/E-4
[ ] R4 1K uppright E- 4
[ ] R5 82R upright D/E-4
Remember: The Quartz must be
installed a little bit above the PCB!
[ ] Q1 4,915MHz HC49U D-4/5
[ ] Q2 4,915MHz HC49U D-5
[ ] Q3 4,915MHz HC49U D-5
[ ] Remove the help wires you used to install the Xtals!
Left and right next to the Quatzfilter there are holes to connect the
enclosures of the Xtals to ground. Use a piece of wire and solder it between
ground connection points and quartz housings. Solder at half the height of

Rev:Nobember 20. 2006
15
every quartz, cleaning with a glass brush or similar tool makes soldering at
the Quartz housing easier.
[ ] Quarzhousings to ground.
[ ] R25 6,8K supright D-4
[ ] C8 150pF COG (150p or 151) D-4
[ ] R6 56K upright D-5
[ ] C12 47nF (473) C/D-5
[ ] R7 56K upright D-5
[ ] C10 150pF (150p or 151) D-4/5
[ ] P6 10K Potentiometer SMC-10-V C/D-4
The following diodes do not have the standard glas or plastic housing but
are built into a TP92 Transistor housing. They look exactly like a little
transistor with only 2 legs plus a very short 3rd leg in the middle. If you
install it, take care to leave a little distance between the PCB and the short
3rd leg to avoit shortening the two solder pads.
[ ] D8 BB112 D/E-5
[ ] D9 BB112 D/E-5
Attention, Transistors are ESD sensitive.
[ ] T11 BF199 E-3
[ ] T2 BF244B D/E-4
Now another coil. L3 which is very similar to the others:
Resonate winding: 18 turns 0,1mm laquered wire between PIN 2 and PIN 1
Coupling winding 4 turns 0,1mm laquered wire between PIN 4 and PIN 3
[ ] L3 Neosid 7.1 F10b D-4
You now may install the IC into their sockets. Don´t interchange them,
apply the notch to the correct side (according to the placement plans, both
nothes look to the right side. ATTENTION: remeber ESD rules!!
[ ] IC1 74HC04 D/E-3
[ ] IC2 74HC4066 D/E-3/4
All ok? Dont forget to recheck your work with a magnifier. Please do not let
out this step. OK, I know you are doing a good job here, but > 90 % of kits
I get for support fail due to soldering failures!
The BCR Receiver now is nearly complete. AF and IF are ready installed, the
mixer is on board, only stage missing to be ready to receive signals is the
„Frontend“ with Preselector and Low Pass filter. However, you can test the
complete IF part now. The link we used in the section before this time is
not needed because the Mixer does a direct connection between IF and DDS
Generator.
As you know, the BCR RX and TX frequency are generated in a different way:
in TX mode the DDS VFO is working directly on the end frequency, in RX
mode the DDS is shifted by the IF frequency. To make the RX listening on
the correct frequency, the IF frequency mut be known exactly to the PIC to
calculate the shift. The middle frequency of Ladderfilters in principle is
somewhat lower the the frequency of a single Quartz. With the help of the
integrated IF generator, we now must find the individual middle frequency
of your BCR.
Attach the headphones and powersupply.
Attach a Voltmeter at the upper end of R14. (If you own an needle
instriment, use it. A Digital Voltmeters will do the job also, but with a
needle Voltmeter it´s more comfortable because you better see tendencies
while adjusting).
• Adjust the ferrite caps of L3, L4, L5. The upper end of the cap should be
abt 1-2 mm below the copper can.
• Switch S1 to SSB ( toward Display = AM)
• Adjust C29 to it´s half capacity position (you can see the plates through
the foil)
• Switch on your BCR.
• Adjust P6 counterclockwise to its end, then back abt 10 degrees clockwi-
se.
• Adjust P5 to about 200mV at R14. Switch to AM. You will see a diffe-
rent, lower reading. The difference should not exceed 100mV. Leave the
switch in AM position.
• Go to Menu, Setup, ZF. The display shows the actual generated IF fre-
quency. Your Voltmeter should read more or less increased Voltage now.

Rev: November 20 2006
16
Change the Generator frequency to lower frequency in small steps and
watch the Voltmeter carefully to find the maximum voltage. The maxi-
mum represents the midpoint of the filter curve. Leave the Generator at
this frequency.
Now adjust L3, L4 and L5 also to Maximum. If all 3 coil are adjusted,
readjust the generator frequency. Repeat the procedure 3-4 times until all
adjustments get stable
Switch S1 to SSB. You should hear two tones in the headphone. One of them
has a stable frequency, it is the sidetone generated by the pic. The other
tone can be varied in it´s frequency by C29. This tone is the result of
mixing the IF signal with the BFO in the product detector. The frequency
represents the shift between IF Frequency and BFO frequency. ( if you
dont hear the sidetone, you probably didn´t adjust it´s loudness in the AF
section, do it now)
If you hear both tones, adjust the BFO Tone. While turning C29 around
you will find zerobeat, that´s the point where IF and BFO are at the same
frequency, resulting in a zero Hertz tone. At both sides of zerobeat you
will find the same audible tone, this are the two sidebands. Adjust C29 to
the side of greater capacity until it has exact the same frequency as the
sidetone. If it is adjusted correctly, both tones will be heard as 1 tone
with a little jamming on it. Leave the menue by choosing „save“ at the
right side of the display.
Grroup 6 LPF, RX Frontend,
Preselector
In this section you will complete the
receiver. After finishing, you will be
able to use it as an RF Receiver.
Attention: If you plan to install
the 80m Option, pay attention to
special advise at some places.
[ ] C73 10pF (10p) F/G-1 [ ] C74 47nF (473) F-1
[ ] C75 47nF (473) F-1 [ ] D12 BAT42 o.ä. F/G-1
[ ] D13 BAT42 o.ä. F/G-1 [ ] R48 39K upright F-1
[ ] R49 39K upright F-1 [ ] R51 100R F/G-1
[ ] R46 100R upright G-1 [ ] R47 100R upright G-1
[ ] R50 1K supright G-1 [ ] C64 1nF (102) G-1
[ ] C72 330pF COG (331) H-1 [ ] C61 1nF (102) G-2
[ ] C70 100p COG (101 o.100p) H-2 [ ] C71 470pF COG (471) H-2
[ ] C69 220pF COG (331) H-2 [ ] C6 47nF (473) G-2/3
[ ] D3 1N4148 G-3 [ ] C62 1nF (102) G-2
[ ] C7 47nF (473) F/G-2/3 [ ] C65 470pF COG (471) F/G-2
[ ] BR1 0 Ohm bridge G-2 [ ] Rel1 DIP-Relais 1xUm 12V F/G-3
[ ] Rel2 Relais bistabil 5V NAIS TQ2-L-5V G/H-2
[ ] Rel3 Relais bistabil 5V NAIS TQ2-L-5V G/H-1/2
Do NOT install the following parts if you plan to install the 80m
Option. If so, go ahead next page to build the Current transformer
which is used by BCR to measure SWR and power later on.
[ ] C68 470pF COG (471) F/G-1
[ ] C67 680pF COG (681) F-2
[ ] C66 180pF COG or Styroflex) (180p /181) F/G-2
[ ] D1 1N4148 F-2/3
[ ] D2 1N4148 F-2/3

Rev:Nobember 20. 2006
17
Building the current transformer and the SWR/Power measuring unit.
You now will handle the first torroid in this kit. It is the smallest one you
have to deal with, it is only 4,5x1,9x2mm and it is made from N30
material, that´s a ferrite. Wind exactly 22 turns trough the ring. I know,
there ares some mistery tales about torroids to hear in the field, but it is
absolutey easy. Just count INSIDE the ring, thats the hole secret. Spread
the 22 turns over the whole ring. This is the secondary winding. The primary
winding consists of only 1 turn. Actually 1 turn does not look like a turn
because it is only a piece of wire through the ring, but that is the trick with
torroids: because all the magnetic field is concentrated inside the ring, it
doesn´t matter what happenes at the outer side of the ring. You may use a
cut of from a resistor to form the primary, because it is easier to solder
then the laquered wire. However, solder the 1 turn primary firs and the thin
secondary after it because you may damage the thin wire if you do it
opposite.
[ ] Tr3 Ringkern N30 4,5x1,9x2 G-1 prim.1 turn 0,5mm wire / sec.22 turns
0,1mm laquered wire.
Ok, that was for training purpose ;-)
If you have done the small transformer with success, you will not have any
problems with the Low Pass Filter Torroids.
ATTENTION: Do not wind or Install L6 and L7 if you plan to install the
80m Option. use the description of L6 only as reference for L9
L6 is a simple Torroid coil wound with 0,4mm laquered wire. If you look at
the holes on the pcb for L6, you will see, that you must take care to wind
these Torroids in the correct direction to meet the layout. How? If you feed
the wire from back to front through the ring, wind the next turns clockwise.
If you feed the wire front to back through the ring, wind the next turns
counterclockwise. The picture shows such a torroid with 8 turns.
OK, lets start. Wind L6 on a yellow Torroid. Count inside the ring, wind 13
turns 0,4mm laquered wire. All turns should be
tautly (tight?) on the ring, if all 13 turns are
made spread them over 2/3 of the ring.
The enamel wire supplied with the kit can be
heat-stripped. A good method to do this is to
place a small amount of solder (a „blob“) on the
end of your soldering iron, then insert the wire into the hot solder
for a few seconds. Avoid scraping insulation off with a razor blade, as this
may nick the wire. Strip and tin the leads of the toroid before you mount it
to the board. You should remove the enamel from the leads up to about 3
mm from the core. You should see only bare wire (no insulation) on the side
to be soldered. Now install the torroid. While soldering hold it tigh against
the board to give it a stable position. Do NOT glue the Torroid to the board.
[ ] L6 Amidon T37-6 13Wdng 0,4mm CuL F/G-2
Now L9, it is wound the same way as L6. Use the same direction for the
winding, use the 0.5mm wire.
[ ] L9 Amidon T37-6 (yellow) 11 turns 0,5mm CuL H-2
The next 2 Torroids must be wound the opposite direction due to the
geometrie of the board. We didn´t do this to annoy you, the geometrie is
the result of some RF rules which claim the wire length of coils to be as
short as possible.
Do not wind L7 if you plan to install the 80m option, use text as
reference forr L8.
Make L7: L7 gets 17 turns of 0,4mm laquered wire on a yellow ring.
Attention, take care the geometrical aspect. If you wind from back to
front, this time wind counterclockwise. If you wind front to back, this time
wind clockwise.
[ ] L7 Amidon T37-6 yellow 17 turns 0,4mm wire F/G-2
To make L8 use the same technik as for L7, but use 0,5mm wire.
[ ] L8 Amidon T37-6 yellow 10turns 0,5mm wire H-2
Ok, now some remaining parts and this section is complete. Remember how
to handle BB12 diodes, avoid shorts by placing them too close down to the
board.

Rev: November 20 2006
18
[ ] D4 BB112 F-3
[ ] D5 BB112 F-3
[ ] D6 BB112 E/F-3
[ ] D7 BB112 E/F-4
Attention: Do NOT install C1 and R3 if you plan to install the 80m
Option!
[ ] C1 3,3pF RM 5mm!! (3p3) E/F-3
[ ] R3 1K upright E-3
[ ] C5 47nF (473) E-5
[ ] R1 68K F-3/4
[ ] R2 68K F-3/4
[ ] C2 47nF (473) F-4
[ ] T1 BF244B E-3/4
The potentiomer P1 must be installed at
C/D 3, there is no extra placement
drawing for this.
[ ] P1 10K Pot SMC-10-V C/D-3
Now again two Bobin coils. You remember them, do you? L2 is easy, it has
only a resonate winding, no coupling winding.
[ ] L2 Neosid 7.1 F10b 11 turns between 1 and 2 0,1 CuL E-3/4
L1 again with two windings. 11 turns between Pin 2 and PIN 1 und 2 turns
between PIN 4 and PIN 3
[ ] L1 Neosid 7.1 F10b F-3
Res. Winding 11 turns 0,1 mm
Coupl. Winding 2turns 0,1 mm
Install the coils plus Ferrit Caps plus shield, do not solder the shield yet.
IF you install the 80m Option, put away this manual now and switch
to the 80m Options manual. You will come back if you have installed
the 80m option.
If you have allready built the 80m Option or if you dont want to use
80m, go on here:
Take a piece of RG174 50 Ohm coax
abt 4-7 cm long. Remove about 1cm
of the insulation at both ends .
Solder one side to a BNC jack and the
other end to the points shown in the
drawing.
As usual, check your work to find
shorts or missing solder points. I
understand, that you are hot to hear
the first signals now, but DO THE CHECK FIRST. Use a Magnifier and bright
light.
Done the check??
OK. Connect your headphones and the power supply.
Preselector Pot to left end, Filter Pot right end, Mode switch to AM
switch your BCR on.
Goto Menu
Choose Radio.
If not changed by yourselfe, the DDS by default is set to 6075 kHz, the
Frequency of „Deutsche Welle“ which should be heard all over Europe very
loud. Outside Europe or if you dont like Deutsche Welle, set the DDS to
another frequency of your choice where a strong BC AM station is working.
You should hear this station now in the headphone.
Attach you Voltmeter to R14 and ground and adjust L1 and L2 „coarse „ to
maximum AGC Voltage. Fine tuning will be done later. The peaks will not be
very sharp.
Now switch to CW/SSB and choose 40m by the menue. Use a dipmeter or a
Signal Generator to produce a 40m signal, couple the signal to the BNC Jack
If you dont have a Signal Generator or a dipper, you may do the following
at a real Antenna with a signal of another HAM.

Rev:Nobember 20. 2006
19
Adjust the Preselector Pot to noise maximum. This is extrem sharp, only a
mm with the knob. Adjusting the Preselector needs some training because it
is so extrem sharp. If the preselector is adjusted, find the Signal with the
VFO. If you do not find it, increase the signal a little bit for the first time.
Now disconnect the generator because this lowers the actual Q of L1 which
makes it harder to adjust. Use some 10cm wire attached to the inner
conductor of the BNC jack as a very short antenna and couple the signal to
this antenna. It must not be loud, it must just be audible.
Adjust L1 and L2 using a nonconductive tool to maximum of AGC Voltage.
Redo adjustment several times using the smallest possible signal. During
adjustment do NOT change the Preselector Pot.
All ok?
Its on your own, what you will do next: listening into the bands or build
the TX parts. I heard from some QRPers that stey stopped soldering for
severals days, while they were playing with their new BCR receiver
However, the TX part does not leave too much work because some groups
are used in the RX as well so they are still built.

Rev: November 20 2006
20
Group 7 Transmitter [ ] R32 10K E-5
[ ] R31 100K E-5
[ ] C45 0,010uF E-5
[ ] R30 3,3K upright E-5
[ ] C46 47nF (473) E-5
[ ] C50 10nF (103) E-4/5
[ ] R39 27R upright E/F-5
[ ] C94=820pF at PCB solder side
parallel to R39 (MODification)
[ ] Dr9 47uH SMCC E/F-5
[ ] C52 10nF (103) F-4/5
[ ] R37 47K upright E/F-4
[ ] R38 330R upright F-4
[ ] R42 680R upright F-4
[ ] C51 47nF (473) F-4
[ ] C53 47nF (473) F-4
[ ] R40 10K upright F-4/5
[ ] C55 470nF Foil spc 5 G-4
[ ] D14 1N4148 G-4
[ ] R45 47R upright G-4
[ ] Dr8 47uH SMCC H-4
[ ] C60 100nF (104) H-4
[ ] C59 1uF Foil space 5 H-3
[ ] C58 10uF 35V rad. H-3
[ ] R41 3,9K upright F-5
[ ] R43 180R upright F-4/5
[ ] R4410R F-4
Attention: ESD rules !!
[ ] T12 BF199 E/F-4/5
[ ] T13 BF199 F-4/5
[ ] T9 BC546B E-4/5
[ ] T10 BS250 E-5
The driver Transistor must be mounted
on the little plastic socket you find in
the kit.
[ ] T14 2N4427 +plastic socket F-4
[ ] C57 47nF (473) F-3/4
The choke for the TX will be wound on a ferrite
because the TX current would be too high for a
standard SMCC choke.
We use an FT37-43 ferrite for the Choke. Again
take care to meet the geometrical
requirements, remember to count the turns
inside the ring.
[ ] Dr7 Amidon FT37-43 10turns 0,5mm
laquered wire F-3
Prepare Dr7 by using the „blob „ method as
you did it in the LPF section.
[ ] C54 47nF (473) G-4
[ ] C56 47nF (473) G-4
Now a new thing, a transformer wound on a double hole core, a so called
PigNose. Because this is new and bacause I know that often mistakes where
made with pignoses, I will give a detailed description how to do. It is easy,
but you must know some facts.
The transforme is used to transform the high output impedance of the
drivers collector to the low input impedance of the PA Base. So we need a
step down transformer. Because it must work between 3,5 and 18 MHz, it
must be a broadband transformer. Such broadband transformers usually are
wound on Ferrite materials which give us high
inductivity with minimum number of turns which
results in low capacity between the turns.
Lay the pignose flat in the table, the holes looking
left to right as you see in the drawing right.
See how a complete turn in a pignose is formed:
Upper left to upper right
and back