50 Mhz Digital Dial.brd

50 MHz Digital Dial
Introduction
This is a frequency counter using the PIC 16F628 that includes an offset function.
This enables you to measure the Local Oscillator frequency in your rig and subtract
the IF to come up with your carrier frequency.
Designed by DL4YHF and featured on his page at
http://www.qsl.net/dl4yhf/freq_counter/freq_counter.html
The board that I have designed to use 4 Digit 7 segment LED display boards which I
have. They utilize the HD1077O high efficiency displays.
A FET input preamp with two buffer stages is included on the board using mostly
SMD components. If your rig provides enough input to the counter you may bypass
it using JP3 on the board.
I have a number of display boards with displays included and some without. Some
have connecting pins, some don't (you can just solder compent lead cutoffs into the
holes). If you purchase this board and wish to also purchase the display board
please contact me. The display board without the displays is $6. With the displays
and with or without pins is $12.
Constrution Notes
The preamplifier may not be required based on your rigs LO output. If it isn’t there is
no need to populate the board with its components and you may use a jumper on JP3
to bypass the preamp entirely.
 There is one component mounted on the bottom of the board (R100). It is the 10k
resister which pulls the PRGM input high. If you are constantly in program mode
you might have forgotten to install this resistor.
 With Flat side up the regulator is Out/Gnd/In from right to
left looking at the bottom. If your regulator isn’t this
pinout you can turn it to make it work.
 That is all I have for now. If I receive any other questions
I will update this document.

Good luck and 73.
Kevin, W8VOS
[email protected]
50 MHz Digital Dial Parts List
Qty
8
2
2
1
1
1
1
1
2
2
1
1
1
1
2
2
1
1
1
1
1
Value
Name
R1, R2, R3, R4, R5, R6,
220
R7, R8
4.7K
R9, R15
1K
R10, R14
1M
R11
390
R12
10K
R13
240
R16
10k
R100
0.1uf
C1, C2
10uf
C3, C8
0.01
C4
22pf
C5
0.1
C6
9-35pf
C7
1N4148
D1, D2
2N2222
Q2, Q3
20MHz
X1
7805L
IC1
E0028-OB
DIS1
MPF102
Q1
PIC16F628P
IC2
Description
1/8 W Axial
SMD
SMD
SMD
SMD
SMD
SMD
SMD
Resistor 1206
Resistor 1206
Resistor 1206
Resistor 1206
Resistor 1206
Resistor 1206
Resistor 1206
mono cap
Electrolytic cap
mono cap
mono cap
mono cap
trim cap
1N4148DO35-7
2N2222
Crystal
7805L Voltage Regulator
4 Digit Seven Segment Display Board
J-FET
PIC16F628P

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