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
____ R1 510 Green
____ R3 1K0 Brown
____ R7 4K7 Yellow
____ R8 22K Red
____ R2 51K Green
____ R6 68K Blue
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.