OCXO AND CLOCK DISTRIBUTION SYSTEM

As used with VE2ZAZ Controller

Jacques Audet VE2AZX

June 2011

Rev. June 2014

Regulator

12V

+16V

INPUT0.4 A to

1.1 A max

10 MHz

+7.3 dBm

15 dB

gain

ZFSC-8-1

MiniCircuits

Power

Splitter 1: 8

+21 dBm

+12 dBm

+12 dBm

+12 dBm

+12 dBm

+12 dBm

+12 dBm

+12 dBm

+12 dBm

+15V

REAR FRONT

Q-Bit

QB-188

+

HI-Pass

Match

9.25 dB

Loss

12

BLOCK DIAGRAM

MV89A

OCXO

Vc

V1

-5 to +5V

smaVref

10K10K

20K

10 MHz set

@ V1 = 0

1K750

250

Scaling

adjust

MV89A OSCILLATOR MODULE

VE2ZAZ GPS CONTROLLER

10 MHz

InputVCXO

CONTROL

VOLTAGE

+5V0 to +5V

Circuit added to provide 1 e -11 tuning resolution with +/- 5 V tuning on VE2ZAZ Controller. It also attenuates and offsets the +/- 5V control voltage to the 0 to +5V range required by the MV89A.The 10K pot allows centering the OCXO at exactly 10 MHz with 0V at the V1 input.This decreases the control voltage dependance on supply variations in the GPS controller.

10K

Gnd

+12V

HI PASS MATCHING CIRCUIT AT THE SPLITTER INPUT

The matching circuit transformsthe Q-Bit amplifier output Z (62 – j1.45 ohms, measured) to a value very close to 50 ohms at 10 MHz.This MAXIMIZES the port to port isolation of the 1 : 8 splitter.

A high pass matching circuit is used to prevent degradation of the return loss at frequencies above 10 MHz.This also MAXIMIZES the portto port isolation at the 10 MHzharmonics.

Return Loss simulation atthe input of the matchingNetwork, around 10 MHz.

Return Loss simulation atthe input of the matchingNetwork, at 10 MHz and above.

Matching Network simulationThe main components are labeled L and C

Vctrl

+16 V IN

+12 V REG

ZFSC- 8-1

QB-188

MV89A

OCXO

X 2.529Cabinet: Hammond 1455T1601

10 MHz

Adj

PI Filter PCB

MATCHING

CKTIN

OUT

GND

MV89A

OCXOVref

Vc

+12V

GND

RF

TOP VIEW

R3

R2

R1

C1

125 1251.5

PCB

PI Filter

1.85

100

Cabinet

SIDE VIEW

spacer

MV89A

OCXO

2.2

2.9

PI Filter PCB

L1

C5

C4

L2

2.00.45

1.6

0.4

1.7

Components

50

9339 washer

120

2 po.

6.5 po.

202

702

POWER 10 MHz OCXO AAZZXX

0.500 in

1.28

2.555

POWER OCXO & CLOCK DISTRIBUTION AAZZXX

OUTPUTS

10 MHz

+ 12 dBm

POWER OCXO & CLOCK DISTRIBUTION AAZZXX

OUTPUTS

10 MHz

+ 12 dBm

L1, L6: Coilcraft 1812PS-333KLB

Remove R7 to R9And insert 5 MHz Notch Filter here

5 MHz Notch Filter

The 5 MHz output was – 45 dB down on my OCXO. See slide 16This notch filter adds more than 50 dB rejection at 5 MHz

Simulated circuit

ISOLATION OUT 1 TO OUT 2

ISOLATION OUT 1 TO OUT 4

ISOLATION OUT 1 TO OUT 8

S11 AT HI-PASS MATCHING OUTPUT

S11 AT HI-PASS MATCHING OUTPUT

Sine Output at Splitter OUT

MV89A

OCXO 10 MHz+7.3 dBm

Vc

V1-5 to +5V

smaVref

10K10K

20K

10K

10 MHz set

@ V1 = 0

1K750

250

Scaling

adjust

Scaling and Frequency Adjust Circuit

MV89A Homemade PCB

Completed System

MV89A

8 to 1 Splitter

Matching

Supply

FilterAmplifier

As Used with VE2ZAZ Controller

Rear View

Without Controller, Vc IN is shorted

OUTDOOR GPS ANTENNA

PVC Pipe 1 ¼ in.

3 in Pipe CAP

Note added short length of pipe inside

PVC Adapter

3 in. to 1 ½ in.

PVC Adapter

1 ½ in to 1 ¼ in.

Bulkhead Feedthru

SMA to N

Galvanized Steel Plate

To hold the GPS Antenna

Bulkheag Feedthru

SMA to N Mounted on

PVC Adapter

1 ½ in to 1 ¼ in.

PVC Adapter 3 in. to 1 ½ in.

and SMA to N

Bulkhead Feedthru

GPS Antenna with a short length Of RG-174

Mounts on top of PVC Adapter 3 in. to 1 ½ in.

Completed Antenna

attached to the Roof Side