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Frequency Standard/Reference Kit - SOLD OUT
PDF Instructions [826K] courtesy of Jon, EA2SN



Instructions for building the FREQUENCY STANDARD

INVENTORY all the parts against the parts list.

___ 220p CAP            1  C5
___ 1n                  1  C4
___ 100n                3  C1 C2 C3
___ 6 pin header        1  J3
___ jumper              1  RED
___ PCB                 1  PCB
___ 51                  1  R4
___ 510                 1  R1
___ 1k                  1  R3
___ 4k7                 1  R7
___ 22k                 1  R8
___ 30k pot             1  R5
___ 51k                 1  R2
___ 68k                 1  R6
___ 2N3904              2  Q1 Q2
___ 74HC4040            1  U2
___ 78L05               1  U1
___ TCXO 20 MHz         1  U3

____ Remove the 74HC4040 chip from  the DIP socket on the PCB
____ Remove the 16 pin DIP socket from the PCB
____ Remove any residual Aluminum foil

____ Install the TCXO, matching the DOT on the PCB with the TCXO
     Place (melt) a very small amount of solder on one of the TCXO pads
     on the PCB, not the TCXO.
     Place the TCXO on the Pads and solder that pad in place.
     Solder the remaining pads of the TCXO.

INSTALL ALL FIXED RESISTORS

____ R4    51 Green-Brown-Black-Gold
____ R1   510 Green-Brown-Brown-Gold
____ R3   1K0 Brown-Black-Red-Gold
____ R7   4K7 Yellow-Violet-Red-Gold
____ R8   22K Red-Red-Orange-Gold
____ R2   51K Green-Brown-Orange-Gold
____ R6   68K Blue-Gray-Orange-Gold

INSTALL ALL CAPACITORS
____ C5  220p labeled 221
____ C4  1n   labeled 102
note: Straighten the pins on the blue 100n capacitors and mount flush on the PCB
____ C1  100n labeled 104
____ C2  100n labeled 104
____ C3  100n labeled 104

INSTALL THE 3x2, 6 PIN HEADER
____ J3  6 pin header

INSTALL THE IC1. - This IC is STATIC SENSITIVE.
____ xx  Install Socket for U2
____ U2  Insert the 74HC4040 IC into the socket

INSTALL Transistors and Voltage Regulator
Push the next 3 devices about half way thru the PCB
____ U1, 78L05. match package outline with PCB
____ Q2, 2N3904. match package outline with PCB
____ Q1, 2N3904. match package outline with PCB

INSTALL BLUE POT.
Note: This is a single turn pot. Good enough for calibration.
      The PCB has holes for a multiturn pot. You supply.
____ R5  Install the blue 50K (30K on schematic) pot

INSTALL POWER AND SIGNAL WIRES.
____ Solder power supply wires (yours) labeled "+" and "G" at J1
     Note that power supply voltage range is +7 to +15 VDC
____ Solder RF output wires (yours) labeled "O" and "G" at J2
     Use a twisted pair of wires or small coax like RG174

____ Place red jumper over top 2 pins near C5 and R7 (10 MHz setting)
     The middle pins are for 2.5 MHz and lower for 5 MHz.
     Select whichever you want, but for calibration use 10 MHz.

CALIBRATE THE FREQ REF (using a WWV Receiver)
____ Set a receiver to WWV on either 10 or 20 MHz.
     20 MHz is best for daylight reception and 10 MHz is best at night.
     Not sure about the UK or Europe.
     Power up the Freq Ref. Observe polarity.
     Use a 9v battery or a 12 volt source.
     Let the reference stablize for 2-3 minutes.
     If you hear WWV in your receiver, also listen for the Freq Ref.
     It should be within 1 KHz from WWV. If you can't hear it,
     verify that your Freq Ref is working with an oscilloscope.
     Zero beat WWV with the Freq Ref signal by adjusting R5 until
     the heterodyne is beating at less than 1 Hz per second.



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