YouKits EK-1A Operation instructions

EK-1A 3 Band CW QRP Transceiver kit 2014
Assemble manual
EK-1A 2014 3 Band (40m, 30m,20m) CW QRP transceiver kit is easy to build, it has SMD finished by the
factory. There are 2pcs of PCB, the main board and display board. To guarantee the building success, the
display board and main board have been assembled and tested including the MCU, LCD and DDS.

EK-1A 2014 part list
Name Description QTY Mark
Encoder 1
Volume adjustment 1K with on/off 1 AF/SW
Volume adjustment 1
Q9 mounts 1 ANT
Battery socket 1 BAT
Power jack 1 +V
Headphone jack 2 PHONE、KEY
I-inductance 10uH 1 L8
Electrolytic capacitors 470uF 2 C15, C39
Electrolytic capacitors 100uF 2 C27, C28
IF Transformer 2 T1 T2
Toroid Black core 1 T3
Magnetic inductance Red core 2 L1、L2
enamel insulated wire
red、yellow 0.5meter
each
Transistor 2078 1 Q9
LED indicator 5mm red 1 LED
relay EA2-12 2 K1
resistor 680ohm 1 30
3mm*8 screw black Secure 2078 1
3mm nut Secure 2078 1
3mm*5 screw black Secure enclosure 10 Countersunk head
insulation pad Secure 2078 1
Insulating particles Secure 2078 1
Display board Assembled tested 1
Main board SMD finished 1
enclosure 1

3 cores need to made by builder:
Magnetic inductance L1: please use yellow enamel insulated wire, about 20cm, make 12 turns.
Magnetic inductance L2: please use red enamel insulated wire, about 20cm, make 10 turns. As above.
T1 transformer is 8:2, please use red enamel insulated wire, about 15cm, make 8 turns as primary. Use yellow
enamel insulated wire, about 6cm, make 2 turns as secondary. Connect primary to the 2 pads connected to
R26 and Q8, secondary to the pad connected to R23 and ground. As below.
Please install all other parts except Q9 and Q10.

Notice：
1. Please notice the direction of Relay K1, must follow the direction on PCB，also the direction of
Electrolytic capacitors C15,C27,C28,C39, never install them in wrong direction.
2. K1, LED, R30, PHONE are all installed at back side of PCB, please check below pic.
3. After installing all other parts, please install the the back cover and secure the Q9 , solder them to the
PCB and cut the extra leads. Then secure the Q9, but use insulation pad and insulating washer then secure
Q10, as below.

Testing:
Double check all the soldering point then connect power and turn it on. If the current is around 80-90mA,
it’s OK to proceed. Current higher or lower than 90mA, there are issues that must be corrected before
processing.
Plug your headphone to phone jack, put signal generator to ANT, put generator with a 5uV signal, adjust
frequency to 7.100Mhz or close to this frequency, put EK-1A on same frequency, now adjust VC to receive a
700Hz beat frequency, then adjust T1,T2 to max the receiver sensitivity.
Please plug your key to Key/Paddle jack, test key, if it’s OK then testing finished. Now we can finish the
assemble.
Secure the back cover with screws, put studs on the display board and then secure the front cover. Install
two knobs, assemble finished.

DDS Calibration
DDS has been calibrated in factory, if a calibration is needed, please follow below:
1. Power off, press and push V/M/SAV and RIT/SET then power on, showing below on screen then release
these two buttons.
2. Waiting for 2 second, display change to below. Put your frequency counter to DDS testing point, the pad
close to R27.
Now the frequency counter reading should be same as screen display (10000.00KHz), please adjust the
tune knob if adjustment needed, pressing V/M/SAV for 2 second, the screen display below release, push
V/M/SAV again to end.
The 10 memory position will also be reset back to factory when you do the DDS calibration.

30M band MOD
30m band only has RX at factory default, if you need 30m TX, connect “A” (right side of R4) on front display
board, then you have 40m 30m 20m RX and TX.
Youkits
2014-12-06