Assembly details
1.
If you have NWT, Scope or RF voltmeter - we recommend to build the Receiver step by step starting
from building and adjusting of bandpass filter, then T1, crystal filter and then build VFO and other
elements. It would help to easily adjust the receiver during the first power on.
2.
If have no such devices, than build the Receiver by accurately soldering the elements according to
diagram.
Element
Assembly details
Inductance
photo
L2&L3
and
L1&L4–
bandpass filter
L2, L3:
5mm shell – 2pcs.
Wire 0.12mm. 45 turns (9
turns in each section).
(length of wire ~100cm).
Using a knife clean the
ends of wire and fix them
on pins by solder pen.
L1 & L4
Wire 0.12mm. 3 turns.
Over L2, L3. In the middle
of existing winding. Using
a knife clean the ends of
wire and fix them on pins
by
solder
pen.
Put the shields and ferrite
cores to inductors.
~9,3µH of L3
and L3 (in the
middle of a
core)
L5 – VFO
T50-6. 36 turns. Wire 0.35-
0.4 mm
~5.1µH
Transformer T1
toroid T37-2, wire 0.28mm
(length ~40cm). 39 turns.
Start of the winding is pin
3; the end of winding is pin
4.
Then, do one more winding
over the existing winding.
3
turns
by
0.35mm.
Connect the ends to Pin 1
and pin 2
~6.2µH
Prepare the Receiver to first power ON
1.
Connect R8 and R12 potentiometers and 8 Ohm speaker or headphones to board.
2.
Power on the Receiver by ap12V to input pin.
3.
If everything is OK (nothing heating, the current is <50mA), then apply +12V to “+12V RX”
input pin.
4.
Make sure that nothing heating and current is <100mA. You should listen to noise in speaker
(test volume by R12) and the noise of air should be changed while tuning by R8.
Calibration
1.
VFO
needs to get its working range: 5.070 - 5,370 It is comfortable to do by using the frequency
counter – connect it to VFO Out (2 pins on board). By tuning L5 coil and trimmer resistors R7, R9
and capacitor C21 do the range 5.070 - 5,370 MHz.
