Ramsey Electronics FR-10 Assembly And Instruction Manual

FR-10 ? 28

FR-10 10 Meter FM Receiver Kit
Quick Reference Page Guide

Introduction to the FR-10 .............. 4

Circuit Description ........................ 5

Parts List ...................................... 6

Simplified Block Diagram .............. 8

Parts Layout Diagram ................... 9

FR-10 Assembly Instructions ........ 11

Schematic Diagram ...................... 14

Testing and Alignment .................. 20

Enclosure Ideas ............................ 23

Troubleshooting Guide ................. 24

Notes for Advanced Users ............ 25

Ramsey Kit Warranty .................... 27

Price: $5.00
Ramsey Publication No. FR-10
Assembly and Instruction manual for:

RAMSEY ELECTRONICS, INC.
793 Canning Parkway
Victor, New York 14564
Phone [phone]
Fax [phone]

Printed on recycled paper

REQUIRED TOOLS

? Soldering Iron (Radio Shack #RS64-2072)
? Thin Rosin Core Solder (RS64-025)
? Needle Nose Pliers (RS64-1844)
? Small Diagonal Cutters (RS64-1845)
? <OR> Complete Soldering Tool Set

(RS64-2801)
ADDITIONAL SUGGESTED ITEMS

? Soldering IronHolder/Cleaner (RS-64-

TOTAL SOLDER POINTS

232

ESTIMATED ASSEMBLY

TIME

Beginner ..............6.8 hrs

Intermediate ........3.9 hrs

Advanced ............2.9 hrs

FR-10 ? 1

10 METER FM

RECEIVER KIT

Ramsey Electronics Model No. FR-10

Check out the 10 meter action with this simple and fun
to build FM receiver. Receive crystal-clear signals from
thousands of miles away! Ten meters is a fascinating
band! Tune the entire 10 Meter band or the VHF low
Police and Fire band.

? Tunes any 5 MHz portion of the 25 to 35 MHz band.
? Excellent performance, less than 1 uV sensitivity.
? Tuned input, low noise preamp stage.
? True Dual-conversion superhet design with 2 pole

Ceramic High IF and 6 pole Ceramic low IF filters!

? Front Panel Volume, Squelch, and Tuning controls.
? Excellent receiver for beginners and seasoned pros!
? Informative manual answers questions on theory,

hook-ups, and uses - enhances resale value, too!

? Add our case set for a finished ‘Pro’ look. Cases match

all Ramsey products.

? Clear, concise assembly instruction carefully guides

you to a finished kit that works the FIRST time!

FR-10 ? 2

RAMSEY TRANSMITTER KITS
??FM-10, 25 FM Stereo Transmitters
??FM-1,2,3,4 FM Wireless Microphones
??PB-1 Telephone Transmitter

RAMSEY RECEIVER KITS
??FR-1 FM Broadcast Receiver
??AR-1 Aircraft Band Receiver
??SR-1 Shortwave Receiver
??AA-7 Active Antenna
??SC-1 Shortwave Converter

RAMSEY HOBBY KITS
??SG-7 Personal Speed Radar
??SS-70 Speech Scrambler
??TT-1 Telephone Recorder
??SP-1 Speakerphone
??MD-3 Microwave Motion Detector
??PH-10 Peak hold Meter
??LC-1 Inductance-Capacitance Meter

RAMSEY AMATEUR RADIO KITS
??FX Series VHF and UHF Transceivers
??HR Series HF All Mode Receivers
??QRP Series HF CW Transmitters
??CW-700 Micro Memory CW Keyer
??PA Series VHF and UHF Power Amplifiers
??Packet Computer Interfaces
??QRP Power Amplifiers

RAMSEY MINI-KITS
Many other kits are available for hobby, school, Scouts and just plain FUN.
New kits are always under development. Write or call for our free Ramsey
catalog.

FR-10 10 METER FM RECEIVER KIT INSTRUCTION MANUAL

Ramsey Electronics publication NO. MFR-10 Rev. E

First printing: January 1992

COPYRIGHT 1992 by Ramsey Electronics, Inc. 793 Canning Parkway, Victor, New York

14564. All rights reserved. No portion of this publication may be copied or duplicated without the
written permission of Ramsey Electronics, Inc. Printed in the United States of America.

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FR-10 ? 27

The Ramsey Kit Warranty

Please read carefully BEFORE calling or writing in about your kit. Most
problems can be solved without contacting the factory.

Notice that this is not a "fine print" warranty. We want you to understand your rights and ours too! All
Ramsey kits will work if assembled properly. The very fact that your kit includes this manual is your
assurance that a team of knowledgeable people have field-tested several "copies" of this kit straight
from the Ramsey Inventory. If you need help, please read through your manual carefully, all
information required to properly build and test your kit is contained within the pages!

1. DEFECTIVE PARTS: It's always easy to blame a part for a problem in your kit, Before you conclude
that a part may be bad, thoroughly check your work. Today's semiconductors and passive components
have reached incredibly high reliability levels, and it’s sad to say that our human construction skills
have not! But on rare occasions a sour component can slip through. All our kit parts carry the Ramsey
Electronics Warranty that they are free from defects for a full ninety (90) days from the date of
purchase. Defective parts will be replaced promptly at our expense. If you suspect any part to be
defective, please mail it to our factory for testing and replacement. Please send only the defective part
(s), not the entire kit. The part(s) MUST be returned to us in suitable condition for testing. Please be
aware that testing can usually determine if the part was truly defective or damaged by assembly or
usage. Don't be afraid of telling us that you 'blew-it', we're all human and in most cases, replacement
parts are very reasonably priced.

2. MISSING PARTS: Before assuming a part value is incorrect, check the parts listing carefully to see
if it is a critical value such as a specific coil or IC, or whether a RANGE of values is suitable (such as
"100 to 500 uF"). Often times, common sense will solve a mysterious missing part problem. If you're
missing five 10K ohm resistors and received five extra 1K resistors, you can pretty much be assured
that the '1K ohm' resistors are actually the 'missing' 10 K parts ("Hum-m-m, I guess the 'red' band
really does look orange!") Ramsey Electronics project kits are packed with pride in the USA. If you
believe we packed an incorrect part or omitted a part clearly indicated in your assembly manual as
supplied with the basic kit by Ramsey, please write or call us with information on the part you need and
proof of kit purchase

3. FACTORY REPAIR OF ASSEMBLED KITS:
To qualify for Ramsey Electronics factory repair, kits MUST:

1. NOT be assembled with acid core solder or flux.

2. NOT be modified in any manner.

3. BE returned in fully-assembled form, not partially assembled.

4. BE accompanied by the proper repair fee. No repair will be undertaken until we have received the
MINIMUM repair fee (1/2 hour labor) of $18.00, or authorization to charge it to your credit card
account.

5. INCLUDE a description of the problem and legible return address. DO NOT send a separate letter;
include all correspondence with the unit. Please do not include your own hardware such as
non-Ramsey cabinets, knobs, cables, external battery packs and the like. Ramsey
Electronics, Inc., reserves the right to refuse repair on ANY item in which we find excessive
problems or damage due to construction methods. To assist customers in such situations,
Ramsey Electronics, Inc., reserves the right to solve their needs on a case-by-case basis.

The repair is $36.00 per hour, regardless of the cost of the kit. Please understand that our technicians
are not volunteers and that set-up, testing, diagnosis, repair and repacking and paperwork can take
nearly an hour of paid employee time on even a simple kit. Of course, if we find that a part was
defective in manufacture, there will be no charge to repair your kit (But please realize that our
technicians know the difference between a defective part and parts burned out or damaged through
improper use or assembly).

4. REFUNDS: You are given ten (10) days to examine our products. If you are not satisfied, you may

return your unassembled kit with all the parts and instructions and proof of purchase to the factory for a
full refund. The return package should be packed securely. Insurance is recommended. Please do not
cause needless delays, read all information carefully.

FR-10 ? 26

If you've enjoyed this kit, be sure to check out the entire Ramsey kit line.
We have a whole series of nifty synthesized VHF FM Transceiver kits
that not only teach state-of-the-art technology, but are fun and easy to
build, too! Call or write for our catalog.

FR-10 ? 3

FR-10 10 METER

FM RECEIVER KIT

Ramsey Publication No. MFR-10

Price $5.00

TABLE OF CONTENTS

Introduction to the FR-10 ............... 4

Circuit Description ......................... 5

Parts List ....................................... 6

Simplified Block Diagram ............... 8

Parts Layout Diagram .................... 9

FR-10 Assembly Instructions ......... 11

Schematic Diagram ....................... 14

Testing and Alignment ................... 20

Enclosure Ideas ............................. 23

Troubleshooting Guide .................. 24

Notes for Advanced Users ............. 25

Ramsey Kit Warranty ..................... 27

KIT ASSEMBLY

AND INSTRUCTION MANUAL FOR

RAMSEY ELECTRONICS, INC.

793 Canning Parkway

Victor, New York 14564

Phone [phone]

Fax [phone]

FR-10 ? 4

INTRODUCTION

There's not a lot to say about using the FR-10 receiver once its been
correctly built and aligned. If 10 meters is "dead" you'll hear little or
nothing. If Ten is "open" there will be an amazing variety of crystal­clear signals from many thousands of miles away.

In the first serious test of this receiver, booming signals from the US
Northeast and Midwest as well as Scotland and Ireland were logged
from a site in Florida! The strength and clarity of GM4DLU in Scotland
was simply astounding! Another listening session logged a station in
Washington, DC conversing with one in Wisconsin via a repeater in
Dallas!

This receiver is a good project for amateurs wishing to become more
familiar with 10 meter FM before choosing a transceiver, or for those
active on 10 who want an inexpensive receiver to take on trips, keep
in a briefcase or to watch for band openings.

Most Ramsey Electronics can be classified as "Skill Level 1" if we use
the old Heathkit guidelines for ease of assembly. That means that our
kits are intended to be successful for first-time kit builders. This FR-10
FM Receiver is best regarded as a "Skill Level 2" project, and should
not be taken lightly, even by experienced, licensed radio amateurs.

Still, this step-by-step manual is written with the beginner in mind,
because we are well aware of the fascination that Ten Meters and its
maze of repeaters holds for newcomers, which means this could be
your very first kit project. The same holds true for those who just want
to peek in on LOW VHF public service communications without the
cost of a scanner. To be honest, we'd like to see first-time builders
start out with an easier kit such as the Ramsey HR-40 Forty Meter
receiver before assembling the FR-10, but we are confident that you
can construct the FR-10 successfully if you follow this manual
carefully and patiently.

Before beginning the project or even studying the circuit description, it
is worthwhile to develop some prior respect for how much receiver is
packed onto the circuit board. The nine semiconductor devices
(diodes, transistors and IC chips) give the equivalent of about 30 or
more transistors and diodes. And, in addition to four inductors, a

FR-10 ? 25

receivers do not offer much PC board space or real need for
customization or other modifications. These receivers do what they are
intended to do at the lowest price that we are aware of for a tunable
VHF FM receiver with squelch, AFC and generous audio output.
Therefore, while we are certainly interested in hearing about significant
performance improvements, we do not recommend casual modification
attempts.

However, there is one practical customization which could be
undertaken by experienced VHF experimenters who wish to take
advantage of the NE602's ability to accept a crystal resonator instead of
the existing L-C tank circuit. The goal would be a one channel repeater
monitor or dedicated packet receiver. Inductor L3 and associated
capacitors would be replaced by the appropriate crystal tank
components. Remember that the crystal oscillator should be planned to
operate 10.7 MHz above the desired receiving frequency. Please do not
attempt such a project unless you have a clear knowledge of oscillator
design and have reviewed and understood the terms of your Ramsey Kit
Warranty. We regret that the factory cannot offer any assistance in
performing this or any other modification, so... you're on your own, but
that's what experimenting is all about!

A helpful article on the Signetics NE602 IC, including a discussion of
crystal-controlled oscillator configurations, was written by Michael A.
Covington with acknowledged assistance from Signetics personnel,
published with good circuit illustrations in Radio-Electronics magazine
for April 1990 (Vol 61, No 4).

A less complex approach to the same general goal, eliminating the
expense of a crystal and the logistics of adding it to the PC board, is to
"undo" the excellent tuning range we designed into your receiver! This
would require selecting appropriate values for C9,C10 and C12 and
reducing the effect of the varactor tuning to perhaps a 100 KHz swing
for fine tuning purposes only. Try reducing C12 to 1 or 2 pF for starters.

Finally, the only pin of the MC3359 not used in our circuit is pin 15, for
scan control. Perhaps you will come up with some fascinating idea for it!

Again, please be sure that you understand your warranty, and that you
understand your receiver and how to keep it working, before attempting
any modifications.

FR-10 ? 24

The Ramsey FR-series FM receivers are among our most widely-used
and popular kits. The circuit itself, assembly and use are "cut-and-dried."
If your receiver does not work, there is probably either an error in
assembly or a defective part. Following is some help in case you
experience difficulty.

Problem: Receiver completely "dead"- no sound at all.
Check the following:

? First, the cable or plug adapter leading to speaker or phones!
? Battery condition and battery wire polarity and soldering at S1.
? Connections associated with U3, the LM386 audio output IC.

Problem: Receiver "hisses", but NO signals are heard, not even a signal
generator 2 inches away.
First, you need to verify that the local oscillator (NE602, L3, etc.) is
operating. Use another VHF receiver or a frequency counter to verify
oscillator operation. Next, make sure that the 10.24 MHz crystal oscillator
is running by tuning a general purpose HF ("shortwave") receiver to that
frequency. If either oscillator is not running, re-check correctness of parts
and solder joints associated with both oscillator circuits. Further signal­path tracing may be necessary to find your problem.

Problem: Very weak signals
If Q1 is defective or incorrectly installed, very little signal energy will
reach the NE602. If Q2 is defective or installed incorrectly, very little of
the NE602's 10.7 MHz output is getting to the MC3359. Also, be sure that
L4 is peaked correctly.

Problem: Considerable frequency drift or shifting
First, make sure that L3 is soldered securely to the PC board. If you plan
to use the receiver "on the go", you may wish to secure the base of the
coil to the board with reinforcing glue. If the receiver drifts, check all
wiring and components associated with AFC Q3 and pin 11 of the
MC3359.

Problem: Squelch does not function
Re-check all connections and components associated with pins 10
through 16 of the MC3359. Check polarity of C27 and D2. C27 sets the
time constant for the squelch circuit.

SOME NOTES FOR ADVANCED USERS

Unlike Ramsey HF receivers and transmitters, the FR-series of VHF

FR-10 ? 5

crystal and two ceramic filters, there are nearly 60 capacitors and
resistors. Surely, all that should result in a decent receiver! You could
easily spend twice the money plus hours of time trying to gather the
equivalent parts from catalogs and still need to make your own circuit
board.

BUILDING YOUR FR-10 KIT

There are just over 200 solder connections on the FR-10 printed circuit
board. That means your work could be 99% excellent and you could
STILL have 2 or 3 cold solder points or solder bridges. Since this circuit
is more sophisticated than a direct-conversion HF receiver or a simple
transmitter, a beginner or casual amateur could have a harder time
tracing a problem due to a poor solder connection. Therefore, PLEASE
take us seriously when we say that good soldering is essential to the
proper operation of your receiver!

? Use a 25-watt soldering pencil with a clean, sharp tip.
? Use only rosin-core solder intended for electronics use.
? Use bright lighting. A magnifying lamp or bench-style magnifier may

be helpful.

? Do your work in stages, taking breaks to check your work.
? Carefully brush away wire cuttings so they don't lodge between

solder connections.

FR-10 CIRCUIT DESCRIPTION

VHF signals from the antenna are amplified through the tuned input
circuit (L1,C3 and L2,C4) by Q1, a microwave bipolar transistor. Q1's
output is fed to the input of the NE602 IC, an efficient single-package (8­pin DIP) mixer-product detector-oscillator. The tunable oscillator section
of the NE602 is aligned to operate at 10.7 MHz higher than the signal
fed and amplified by Q1. For example, to receive 222-227 MHz signals,
the oscillator must tune 232.7 to 237.7 MHz in order for the NE602's
mixing capability to produce a steady 10.7 MHz output signal to the rest
of the circuit. The oscillator frequency is determined by L3 and its
associated capacitors, and varied by the varactor tuning network using
D1 and varied by R1.

The output from pin 4 of the NE602 passes through a ceramic 10.7 MHz
filter, amplified by transistor Q2 and applied to input pin 18 of U2. Q3
provides AFC (automatic frequency control) by keeping the local