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2 METER FM 5 WATT
TRANSMITTER KIT
Ramsey Electronics Model No.
Here's a simple hard-working transmitter that's ideal for
repeaters, Fox-hunts, remote bases, Packet - you name it! Why
tie up a whole transceiver to just use the transmitter? Fun and
educational to build - you'll be on-the-air in an evening!
•
Direct, true FM for excellent voice and data quality.
•
Both Data and mike audio inputs
•
Solid 5 watt RF output - add our PA-146 for 40 watts
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Crystal controlled with 146.52 MHz crystal included
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Built-in test points for easy tune-up. Align with any
digital multimeter - tuning tool included, too!
•
Runs on 12 - 14 Volts DC at less than 1 amp
•
Easy assembly and hook-up
•
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!
FT146 • 1
FT146
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Summary of Contents for Ramsey Electronics FT146
- Page 1 2 METER FM 5 WATT TRANSMITTER KIT Ramsey Electronics Model No. FT146 Here's a simple hard-working transmitter that's ideal for repeaters, Fox-hunts, remote bases, Packet - you name it! Why tie up a whole transceiver to just use the transmitter? Fun and educational to build - you'll be on-the-air in an evening! •...
- Page 2 Ramsey Electronics publication NO. MFT146 Rev. 1.3 First printing: February 1992 COPYRIGHT 1992 by Ramsey Electronics, Inc. 590 Fishers Station Drive, 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.
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Page 3: Table Of Contents
Price $5.00 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR FT146 FM RECEIVER TABLE OF CONTENTS ntroduction to the FT146 ....4 Circuit Description ......5 Parts List ........6 FT146 Assembly Instructions ..8 Testing and Alignment ....19 Power Supply Considerations ..21 Verifying RF Power Output .... - Page 4 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.
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Page 5: Circuit Description
FT146 CIRCUIT DESCRIPTION Basic overview: The FT146 is a crystal controlled FM transmitter that uses a varactor modulated crystal oscillator followed by a 9 times frequency multiplier and power amplifier. Test points are built-in for easy alignment. -
Page 6: Parts List
"C". A class C amplifier draws no current unless it is driven, so there is no need to switch the later stages on and off. FT146 2 METER FM TRANSMITTER KIT PARTS LIST Capacitors: 2 or 2.2 pf disc capacitor (marked 2 or 2.2 or 2K or 2.2K) [C17] 4.7 or 5 pf disc capacitor (marked 4.7 or 5 or 4.7K or 5K) [C21]... - Page 7 5/16" x 20 bolt (to wind coils on) 1 1/2 feet enameled magnet wire 1 1/2 feet tinned buss wire Required, not supplied: 12 volt DC power source at 1 amp minimum Microphone Dummy load or suitable antenna Enclosure such as the Ramsey CFT FT146 • 7...
- Page 8 RAMSEY Learn-As-You-Build KIT ASSEMBLY: There are over 200 solder connections on the FT146 printed circuit board. That means your work could be 99% perfect and you could STILL have 2 or 3 cold solder points or solder bridges. Since this circuit is more sophisticated than a...
- Page 9 17. Install C34, 10 uf electrolytic capacitor. Remember to observe correct polarity. 18. Install C37, .001 uf disc capacitor (marked .001, 1 nf or 102). 19. Install R17, 47 K ohm (yellow-violet-orange). 20. Install C40, .001 disc capacitor (marked .001, 1 nf or 102). FT146 • 9...
- Page 10 36. Install R26, 10K ohm (brown-black-orange). 37. Install R5, 47K ohm (yellow-violet-orange). 38. Install C24, 100 pf disc capacitor (marked 100 or 101). 39. Install C30, 470 pf disc capacitor (marked 470 or 471). 40. Install R8, 270 ohm (red-violet-brown). FT146 • 10...
- Page 11 44. Install C27, 15 pf disc capacitor (marked 15 or 15K). 45. Install trimmer capacitor, C43 (black body with orange top). This trimmer is used for setting the FT146 exactly on frequency. 46. Install Y1, crystal. This is the "heart" of the FM transmitter, producing the initial signal which is multiplied and amplified up to the final transmitted signal.
- Page 12 This lead towards 74. Install C31, .001 uf disc capacitor (marked .001 or 102). 75. Install C17, 2 or 2.2 pf disc capacitor (marked 2 or 2.2). Nine parts need handmade preparation before installation in the transmitter RF FT146 • 12...
- Page 13 Each coil core is 2 1/2 turns and will appear to be 3 turns if viewed from the top. enameled wire tin ends 3 turns through center enameled wire tin ends FT146 • 13...
- Page 14 FT146 • 14...
- Page 15 FT146 • 15...
- Page 16 Wire sits flat 95. Install L10, small ferrite (not a scrap component lead) against board bead RF choke you wound earlier. PC board 1/2 inch 96. Install C6, 100 pf disc capacitor (marked 100 or 101). FT146 • 16...
- Page 17 VHF performance. This part is different from other metal can transistors in that the case is connected internally to the emitter rather than the collector. This provides much higher gain at VHF frequencies. FT146 • 17...
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Page 18: Testing And Alignment
Icom/Yaesu/Radio Shack microphone plugged into jack J2. This completes our assembly of the FT146 two meter FM transmitter. Now's a good time to give your masterpiece a good going over, being especially alert for any: •... - Page 19 L11: 4 turns 2. Rotate modulation control R13 fully counter-clockwise. 3. Apply 12 volts to the FT146 transmitter board. Its a good idea to fuse the power to the FT146, 1 to 2 amps will do. 4. Connect a proper 50 ohm dummy load to antenna connector J1. In a pinch, a light bulb may be used - see the section "Verifying Transmitter RF...
- Page 20 C43 for exactly 146.520 MHz. If you do not have such equipment, use a receiver with a center tune meter. This completes the alignment of your FT146. The PC board should be mounted into a protective enclosure to guard against accidental contact. The Ramsey CFT case set provides an ideal, perfectly sized and matched case for your FT146.
- Page 21 8.2 ohm load to the transmitter. Because of this, the transmitter may act "flakey" when tuning up into a light bulb, and by all means you should not consider a light bulb an accurate indicator of the FT146's performance!
- Page 22 This proceedure will lead us to the final amplifier stages where we can pretty much do a thourough visual inspection. Common problems to look for are solder bridges or interchanged capacitors - FT146 • 22...
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Page 23: Microphone Considerations
MICROPHONE CONSIDERATIONS During assembly, the FT146 was jumpered for using an Icom style microphone plugged into the mike jack J2. You may also use the rear panel 5 pin DIN jack, P1. If you decide to do so, change the "Audio In" wire jumper to go between A and B. -
Page 24: Crystal Requirements
CRYSTAL REQUIREMENTS The FT146 transmitter uses a crystal at 1/9 the final carrier output frequency. This is a fairly common type of crystal that is found in many of the older "rock- bound"... - Page 25 LED, controls, antenna and microphone connectors. [B]: Order from RAMSEY ELECTRONICS: Most RF and VHF transistors, coils, crystals, PIN diodes, varactor diodes, trimmers, IC chips. [C]: U1 is a common dual op-amp made by many manufacturers and is commonly stocked by most parts stores.
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Page 26: Parts Layout Diagram
FT146 PARTS LAYOUT DIAGRAM FT146 • 26... -
Page 27: Ramsey Kit Warranty
'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... - Page 28 • Digital Multimeter Ramsey M133 Price: $5.00 Ramsey Publication No. FT146 Assembly and Instruction manual for: RAMSEY MODEL NO. FT146 2 METER FM TRANSMITTER KIT RAMSEY ELECTRONICS, INC. 590 Fishers Station Drive Victor, New York 14564 Phone (585) 924-4560 FT146 • 28 Fax (585) 924-4555 www.ramseykits.com...