Group build
proposal
Michael G3WOE
MISSION
A £10 radio for
Whitton Members
BITX
Group build
project
A new mission with a Previous Club Projects
•Satellite Award. AO51
worthwhile and tangible •Satellite tracking system.
•CQWW entries (48 hour).
outcome. •CQ WPX contest entry.
•IOTA entry.
To provide a new practical Individual Projects
focus for the club meetings. •EME moonbounce. (G1KAW)
•VLF to USA. (G0MRF)
Why this design?
Good performance at very low cost
Minimalistic design providing really useful
functionality
Uses main components bi-directionally.
Where possible the same components are
used for both transmit and receive.
Interesting design which performs very well
BITX transceiver
Essentially we are building
a transmitter which works
in both directions.!!
IRF510
6w PA Low Pass
Filter
A L U
10MHZ
Mixer/ Sideband Band
Amp Amp Amp Mixer Amp Pass Filter
14 MHZ
Mod Filter
BI DIRECTIONAL
BFO VFO
TX TRANSMITTER
9.999 MHZ 4 MHZ
BITX transceiver
Audio Amplifier
IRF510
6w PA Low Pass
Filter
10MHZ
Mixer/ Sideband Band
Amp Amp Amp Mixer Amp Pass Filter
14 MHZ
Mod Filter
BI DIRECTIONAL
BFO VFO
TX TRANSMITTER
9.999 MHZ 4 MHZ
TO BAL MOD
SCHEMATIC
AUDIO AMPLIFIER
BITX transceiver
BFO and Balanced
Modulator
IRF510
6w PA Low Pass
Filter
10MHZ
Mixer/ Sideband Band
Amp Amp Amp Mixer Amp Pass Filter
14 MHZ
Mod Filter
BI DIRECTIONAL
BFO 10MHZ VFO
TX TRANSMITTER
9.999 MHZ 4 MHZ
The mixing process
10mhz BFO 10mhz carrier Signal we need
UNWANTED IMAGE
AUDIO X = LSB USB
LSB USB
BALANCED MIXER ALSO SUPRESSES THE CARRIER
TO SIDEBAND FILTER
BFO BALANCED MODULATOR
10MHZ CRYSTAL TO AUDIO
SCHEMATIC
BALANCED MODULATOR
BITX transceiver
Bi-directional buffer
amplifier. (I.F. 10Mhz)
IRF510
6w PA Low Pass
Filter
10MHZ
Mixer/ Sideband Band
Amp Amp Amp Mixer Amp Pass Filter
14 MHZ
Mod Filter
BI DIRECTIONAL
BFO VFO
TX TRANSMITTER
9.999 MHZ 4 MHZ
SCHEMATIC
BI-DIRECTIONAL IF AMPLIFIER
BITX transceiver
Sideband filter
IRF510
6w PA Low Pass
Filter
10MHZ
Mixer/ Sideband Band
Amp Amp Amp Mixer Amp Pass Filter
14 MHZ
Mod Filter
BI DIRECTIONAL
BFO VFO
TX TRANSMITTER
9.999 MHZ 4 MHZ
SCHEMATIC
SIDEBAND FILTER. 4X10MHZ CRYSTALS
BITX transceiver
Bi-directional IF Amplifier 2
IRF510
6w PA Low Pass
Filter
10MHZ
Mixer/ Sideband Band
Amp Amp Amp Mixer Amp Pass Filter
14 MHZ
Mod Filter
BI DIRECTIONAL
BFO VFO
TX TRANSMITTER
9.999 MHZ 4 MHZ
SCHEMATIC
BITX transceiver
Mixer/up convertor
IRF510
6w PA Low Pass
Filter
10MHZ
Mixer/ Sideband Band
Amp Amp Amp Mixer Amp Pass Filter
14 MHZ
Mod Filter
BI DIRECTIONAL
BFO VFO
TX TRANSMITTER
9.999 MHZ 4 MHZ
TOWARDS USER
10MHZ IF
TOWARDS
AERIAL 14MHZ
VFO 4-4.4MHZ
SCHEMATIC
MIXER
BITX transceiver
VFO. Variable Frequency
Oscillator. (Tuner).
IRF510
6w PA Low Pass
Filter
10MHZ
Mixer/ Sideband Band
Amp Amp Amp Mixer Amp Pass Filter
14 MHZ
Mod Filter
BI DIRECTIONAL
BFO VFO
TX TRANSMITTER
9.999 MHZ 4 MHZ
TUNING VOLTAGE CONTROL
MIXER
VARIABLE CAPACITANCE DIODE
SCHEMATIC
VFO
BITX transceiver
RF Amplifier
IRF510
6w PA Low Pass
Filter
10MHZ
Mixer/ Sideband Band
Amp Amp Amp Mixer Amp Pass Filter
14 MHZ
Mod Filter
BI DIRECTIONAL
BFO VFO
TX TRANSMITTER
9.999 MHZ 4 MHZ
TOWARDS
AERIAL
MIXER
SCHEMATIC
BI-DIRECTIONAL RF AMPLIFIER
BITX transceiver
Band pass filter. 14mhz
IRF510
6w PA Low Pass
Filter
10MHZ
Mixer/ Sideband Band
Amp Amp Amp Mixer Amp Pass Filter
14 MHZ
Mod Filter
BI DIRECTIONAL
BFO VFO
TX TRANSMITTER
9.999 MHZ 4 MHZ
BAND PASS FILTER
FIRST STAGE OF
LINEAR
AMPLIFIER
SCHEMATIC
BAND PASS FILTER
BITX transceiver
6 watt linear amplifier
IRF510
6w PA Low Pass
Filter
10MHZ
Mixer/ Sideband Band
Amp Amp Amp Mixer Amp Pass Filter
14 MHZ
Mod Filter
BI DIRECTIONAL
BFO VFO
TX TRANSMITTER
9.999 MHZ 4 MHZ
BITX transceiver
Low pass filter
IRF510
6w PA Low Pass
Filter
10MHZ
Mixer/ Sideband Band
Amp Amp Amp Mixer Amp Pass Filter
14 MHZ
Mod Filter
BI DIRECTIONAL
BFO VFO
TX TRANSMITTER
9.999 MHZ 4 MHZ
6w linear
Linear
SCHEMATIC
DO NOT WORRY. THIS IS NOT DIFFICULT WHEN TAKEN STAGE BY STAGE
Preparation
Order PCB’s
Decide on case design
Source larger components, knobs etc.
Create bill of materials
Order parts.
0.001u 2 Capacitor
0.1u 44 Capacitor
100p 3 Capacitor
10p 4 Capacitor
2.2p 2 Capacitor
220p 5 Capacitor
47p 3 Capacitor
560p 3 Capacitor
56p 1 Capacitor
elec 1u 2 Capacitor
elec 50u 6 Capacitor
var 22p 6 Var Capacitor
var 365p 1 Var Capacitor
6.2 1 RESISTOR 1/4W
10 9 RESISTOR 1/4W
22 3 RESISTOR 1/4W
56 1 RESISTOR 1/4W
100 13 RESISTOR 1/4W
220 14 RESISTOR 1/4W
470 3 RESISTOR 1/4W
10k 4 RESISTOR 1/4W
120k 2 RESISTOR 1/4W
1k 14 RESISTOR 1/4W
220k 1 RESISTOR 1/4W
2k2 2 RESISTOR 1/4W
2k2 9 RESISTOR 1/4W
4k7 3 RESISTOR 1/4W
lin 100 1 RESISTOR 1/4W
lin 10k 2 RESISTOR 1/4W
10MHz 5 XTAL
BC546 or 2N2222 14 TRANSISTOR
IRF510 1 TRANSISTOR
2N2218 1 TRANSISTOR
LM386-N1 1 IC
zener 36V 1 DIODE
zener 9.1V 1 DIODE
zener 5.6V 1 DIODE
1N4148 13 DIODE
Microphone 1
Loudspeaker 8ohm 1
Relay 12v 3
QRP
•This q code stands for
LOW POWER
•Hams who use low power
also tend to build their own
often portable equipment.
•QRP followers tend to
focus on homebrew skills
CREDIT AND THANKS TO VU2ESE
“THIS IS THE CURRENT VIEW OF MY WORK BENCH AS ON APRIL
24TH, 2008.
EXCEPT FOR THE TEKTRONIX 465, EVERYTHING IS HOMEBREWED”.
ASNHAR FARHAN
USEFUL PUBLICATIONS
Useful web sites
This presentation will be uploaded to the forum and to the Whitton web site/blog
http://www.phonestack.com/farhan/bitx.html
http://uk.groups.yahoo.com/group/TheWhittonARG/
http://groups.yahoo.com/group/BITX20/?yguid=345589192
http://www.norcalqrp.org
http://www.gqrp.com/
Thank you
G3WOE
