Ramsey Electronics FX Series User Manual

220 MHZ AMATEUR PLL
SYNTHESIZED FM
TRANSCEIVER 220 - 240
Ramsey Electronics Model No. FX-223
Published in Three Sections:
• FX-series General Reference Information
• Kit Assembly Phase I: Circuit Stages A through F
• Kit Assembly Phase II: Circuit Stages G through TX
Plus:
• Fold-out Schematic Diagram
• Synthesized - no crystals to buy !
• Perky 5 watt RF output
• Dual conversion sensitive receiver with crystal and ceramic IF filters
• PACKET ready ! Dedicated packet interface connector on back!
• 12 Channels, expandable to as many as you want - programmed with
diodes !
• Easy 4 evening assembly - need only a voltmeter and another rig for
testing
• Fantastic manual teaches as you build, rig is assembled in bite-sized
sections that are tested as you build - your kit will work first time !
• Rig operate over 20 MHz of band, great for snooping out of band !

Ramsey Electronics FX Series Specifications

General

Brand	Ramsey Electronics
Model	FX Series
Category	Transceiver
Language	English

Summary

FX-223 General Reference Information

IMPORTANT NOTICE

Provides critical operational and safety information for the FX-223 transceiver.

SPECIFICATIONS FOR THE RAMSEY FX-223

Details the technical parameters and capabilities of the FX-223 transceiver.

INTRODUCTION to FX-series VHF Transceiver Kit Assembly

Offers an overview of the kit's philosophy and design approach for builders.

A MESSAGE TO HAM RADIO BEGINNERS:

Guidance and encouragement for newcomers to ham radio building.

DC POWER SUPPLY CONSIDERATIONS :

Essential advice on selecting and using appropriate power sources for the transceiver.

ENCLOSURE & HARDWARE CONSIDERATIONS:

Discusses options and recommendations for housing and finishing the transceiver.

THE RAMSEY CFX TRANSCEIVER ENCLOSURE KIT:

Details the components and assembly of the optional CFX case kit.

GUIDE TO PC BOARD I/O CONNECTIONS:

Explains the purpose and connection points for various jacks and features on the PC board.

MICROPHONE & SPEAKER INFORMATION

Details compatible microphones, speakers, and audio connections.

A FEW ANTENNA CONSIDERATIONS

Provides advice on selecting and building antennas for VHF operation.

VHF PACKET DATA OPERATION

Describes how to set up and use the transceiver for packet radio communication.

FX-223 CIRCUIT OVERVIEW

Provides a high-level explanation of the transceiver's main circuit blocks and functions.

KIT ASSEMBLY: PHASE 1

Stage A: DC Power Regulation & Distribution Plus Packet Data I/O Connector

Covers installation of power input, regulation, and the packet data connector.

Stage B: Receiver Audio Amplifier

Details the assembly and function of the audio amplifier stage for the receiver.

Stage CR: Integrated FM Receiver

Explains the dual-conversion superhet receiver circuit using the MC13135 IC.

Stage DR: Receiver, Tuned RF Input and Preamp

Covers the RF input and preamplifier stages for signal reception.

Stage E-F: Transceiver VCO with Buffer Stages

Describes the assembly and function of the Voltage Controlled Oscillator and its buffer stages.

KIT ASSEMBLY: PHASE 2

Stage G: Understanding and Building the PLL Frequency Synthesizer

Explains the PLL synthesizer IC, its concepts, and assembly.

Stage H: Building and Programming the Diode Matrixes

Covers frequency programming using diode matrixes and understanding their function.

Stage M: Microphone Amplifier and PTT Circuit

Explains the microphone amplifier and push-to-talk (PTT) switching.

Assembly Stage "TC": Preparing Transmitter Coils, RF Chokes

Instructions for preparing specific coils and RF chokes for the transmitter.

Assembly Stage "TO": Programming Standard Repeater Offsets (- 1.6 and + 1.6 MHz)

Covers programming standard repeater offsets for transmit.

Stage TX: Transmitter Buffer, Driver and Final

Details the assembly of the transmitter buffer, driver, and final output stages.

THE RX/TX OFFSET PROGRAMMING MATRIX

TRANSCEIVER PLL ALIGNMENT (May also be done before Step TX35)

TEST PROCEDURE:

Step-by-step instructions for aligning the PLL and verifying transmitter functions.

BUILDING THE LOW PASS FILTER PC BOARD:

TRANSMITTER COMPLETION AND TUNEUP

IMPORTANT:

Critical notes and warnings before proceeding with final transmitter setup.

FX-223 TECHNICIAN’S NOTES

VCO & PLL Faults:

Transmit Section Faults: