80 Meter Band VCXO Kit (for Universal Receiver)
The parts in this VCXO Kit are designed for 80 Meter reception from ~3,553 to ~3,563 kHz (without C7).
The 10 MHz IF used in the Kit makes it a good candidate of DDS operation.
The Kit includes the following parts/items:
L1 FT37-61 36T#30Red
L2 FT37-61 14T#27Red
L3 FT37-61 16T#27Red
T1 T37-1 (Blue) 31T#30Red::4T#27Red
C3 180pF NPO (marked 181J)
C20,21 120pF NPO
C6,8 47pF NPO (marked 470)
C9 4p7
C14,15,16,17 680pF NPO (marked 681)
X5 13.56 MHz VCXO Crystal
X1,2,3,4 Matched 10.000 (filter center ~ 9,995.6 kHz)
35 inches Red #27 magnet Wire
40 inches Red #30 magnet Wire
Install all the below parts in the order given.
_____C3: Install 180pF Capacitor (marked 181J)
_____C6,8: Install 47pF VCXO Feedback Capacitors (DO NOT INSTALL IF USING A DDS)
_____C9: Install 4p7cap - this cap expands the VFO coverage from ~3,529 to ~3,563 kHz - DO NOT INSTALL IF USING A DDS
_____C12: Install 100n Capacitor - ONLY IF USING A DDS
_____C14,15,16,17: Install 680pF Capacitors - establish crystal filter bandwidth
_____C20,21: Install 120pF BFO Capacitors; because of 0.1 inch lead spaing, install in the left and center holes
Wind and install all Toroid Inductors. Wind all wires on the toroids clockwise.
_____T1: Install RF Bandpass Transformer.
Cut 20" of #30 red wire and tightly wind 31 turns on T1, a Blue T37-1 toroid
Cut 6" of #27 green wire and wind 4 turns
Trim the #30 red wires to one inch.
Trim the #27 green wires to half inch.
Tin/solder the wire ends to the base of the toroid using a hot solder pencil.
Spread the turns over most of the toroid.
Install T1 with the #30 wires into the outside (upper and lower) holes on the PCB
and the 4 turns #27 wire thru the center holes for T1.
Pull the wires tight on the bottom of the PCB and solder, then trim.
You should be able to straighten the toroid to match the outline on the PCB.
_____L1: Install Series tuned Inductor
Cut 24" of #30 red wire and tightly wind 36 turns on L1, a black FT37-61 toroid
Trim the #30 red wire to one half inch.
Tin/solder the wire ends to the base of the toroid using a hot solder pencil.
Spread the turns over most of the toroid.
Install L1 on the PCB
Pull the wires tight on the bottom of the PCB and solder, then trim.
You should be able to straighten the toroid to match the outline on the PCB.
_____L2: Install Series Tuned VCXO Inductor (use holes A & C) DO NOT INSTALL IF USING A DDS
Cut 12" of #27 red wire and wind 14 turns on L2, a black FT37-61 toroid
Trim the #27 red wire to one half inch.
Tin/solder the wire ends to the base of the toroid using a hot solder pencil.
Spread the turns over most of the toroid.
Install L2 on the PCB
Pull the wires tight on the bottom of the PCB and solder, then trim.
You should be able to straighten the toroid to match the outline on the PCB.
_____L3: Install Series Tuned BFO Inductor
Cut 12" of #27 red wire and wind 16 turns on L3, a black FT37-61 toroid
Trim the #27 red wire to one half inch.
Tin/solder the wire ends to the base of the toroid using a hot solder pencil.
Spread the turns over most of the toroid.
Install L3 on the PCB
Pull the wires tight on the bottom of the PCB and solder, then trim.
You should be able to straighten the toroid to match the outline on the PCB.
_____X5: Install 13.56 MHz VCXO Crystal - DO NOT INSTALL IF USING A DDS
_____X1,2,3,4: Install 10.000 MHz IF Crystals