Instruction manual

ManualsBrandsRamsey Electronics ManualsAmplifierPA1

PA-1 • 1

2 METER RF POWER

AMPLIFIER KIT

Ramsey Electronics Model No. PA1

• Works with any radio; mobile, fixed or handheld

• 8 to 10 times the power gain: 10 watts out for every 1 watts in, 20 watts

out for every 2 watts in, 30 watts out for every 3 watts in!

• Easy connection to a radio

• Operates on 12 - 14 volts DC, draws a maximum of 5 amps

• Just add a T-R relay, case, Pre-amp if desired and connectors

• Informative manual answers questions on theory, hookup and uses -

enhances resale value, too!

• Maximum output of 35 - 40 watts, max drive of 8 watts

• Mounts in any small aluminum case, which then will act as a heatsink

• Yes, this is the amplifier that’s been reviewed in all the Ham magazines!

• Clear, concise assembly instructions carefully guide you to a finished

kit that works FIRST time!

Give your handheld a big boost with this economical power

amplifier kit. Thousands have built and enjoyed this kit; one

magazine review even said, “probably the best bargain in Ham

radio!”

Summary of content (16 pages)

PAGE 1
2 METER RF POWER AMPLIFIER KIT Ramsey Electronics Model No. PA1 Give your handheld a big boost with this economical power amplifier kit.
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PARTIAL LIST OF AVAILABLE KITS RAMSEY TRANSMITTER KITS • FM10, FM25B FM Stereo Transmitters • FM100 Super Pro FM Transmitter • MR6 Model Rocket Tracking Transmitter • AM1, AM25 AM Transmitters RAMSEY RECEIVER KITS • FR1 FM Broadcast Receiver • AR1 Aircraft Band Receiver • SR2 Shortwave Receiver • HFRC 10 MHz WWV Receiver • SC1 Shortwave Converter RAMSEY HOBBY KITS • SG7 Personal Speed Radar • SS70A Speech Scrambler •TG1 DTMF Tone Grabber • BS1 “Bullshooter” Digital Voice Storage Unit • AVS10 Automatic Seque
PAGE 3
Ramsey Publication No. PA1 Price $5.00 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR 2 METER RF POWER AMPLIFIER KIT TABLE OF CONTENTS Kit Building Tips ............................... Parts list ........................................... Assembly.......................................... Parts Layout Diagram ...................... Schematic Diagram .......................... Testing ............................................. Troubleshooting ............................... Transmitting-Receiving ............
PAGE 4
PA1 AMPLIFIER All of us at Ramsey say THANKS for your interest in building the world's most popular 2 Meter amplifier project. Successful construction and installation of your PA1 amplifier can give your handheld 2 Meter transceiver an RF power boost beyond the performance of many fixed and mobile units.
PAGE 5
KIT BUILDING TIPS Use a good soldering technique - let your soldering iron tip gently heat the traces to which you are soldering, heating both wires and pads simultaneously. Apply the solder on the iron and the pad when the pad is hot enough to melt the solder. The finished joint should look like a drop of water on paper, somewhat soaked in.
PAGE 6
ASSEMBLY DIRECTIONS: ❒ 1. Simply EXAMINE the PA1 circuit board. Notice which way is up or down in accord with our published drawing. Notice that ALL components are surface-mounted (tack-soldered) to one side of the PC board. There are NO component-mounting holes! ❒ 2. Taking care that your soldering tip is clean, pre-tin all mounting pads on the board. You are using enough heat if the solder flows VERY easily and remains shiny. That is the only acceptable result.
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PA-1 • 7
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❒ 5b. Tack-solder C1, one of the Mica compression trimmer capacitors, using enough heat for a solid, good connection. ❒ 6. Install C3, the other compression trimmer, just like C1. ❒ 7a. Bend the leads of C2, the round trimmer capacitor, at right angles so that it can also sit in a level and flat position. The two leads at one end go to the ground plane, and the single lead goes to the pad with C1. ❒ 7b. Install C2. ❒ 8. Install C4, just like C2.
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❒ 11a. Using the #18 enameled wire, wind a 5-turn coil for L3. The inside diameter is also 1/4", the turns should be close-wound, and the ends should be 1/4-inch long. Using a small knife or sandpaper, scrape the insulation from each end, tin the bare ends with solder, and gently bend the ends as needed so the coil sits in its position correctly and neatly. ❒ 11b. Install L3. L3 side view ❒ L 3 to p v ie w 12a. The RF choke consists of a ferrite bead with 6 holes.
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make a suitable HEATSINK for Q1 and install it before proceeding. A piece of heavy aluminum or copper the same size as the PA1 circuit board will work fine. Even when securing Q1 to such a heatsink, do not use too much force. Observe the correct orientation of Q1 on the actual circuit board when mounting it to the heatsink. The collector lead (output side) has a 45-degree cut that is plainly visible. ❒ 14. Pre-tin both the upper and lower surfaces of all four leads of power transistor Q1. ❒ 15.
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INITIAL TESTING Required for testing: 1 to 5 watt 2 Meter transmitter or transceiver. 12 volt DC power source, 5 amp minimum. RF wattmeter suitable for VHF use. Correct cables and connectors. 50-ohm 30-50 watt dummy load (use antenna for testing only in accordance with appropriate frequency selection, transmission ID procedures). • • • • • DC voltage may be applied to the PA1 at all times. As a Class C amplifier, it draws current only with RF drive. For the first test, use just 2 or 3 watts of RF drive.
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TRANSMIT-RECEIVE ["T-R"] SWITCHING CONSIDERATIONS: T-R switching of a single antenna with a 2 Meter transceiver and the PA1 RF amplifier may be accomplished in any of these ways: • 1. Internal connections to your transceiver, making use of its built-in T-R switching circuit or relay. • 2. External T-R relay controlled by transceiver microphone switch or relay line. • 3. RF-activated T-R switch such as the Ramsey RFS-1 kit. • 4. PIN-diode T-R switching.
PAGE 13
CUSTOMIZING YOUR PA1 INSTALLATION: Since it's up to you to supply the enclosure, connectors and any desired operating conveniences, it's likely that each one of those thousands of PA1s in use today has its own personality. For some good ideas, take a look at "Turn Your HT into a 40W 2M Mobile Rig" by N8KDD in 73 Magazine, December 1989.
PAGE 14
A NOTE FOR EXPERIENCED BUILDERS ON LINEAR OPERATION FOR SSB, AND OTHER EMISSION TYPES: Please undertake this conversion ONLY if you understand the theory and practice involved. Otherwise, please get help from another ham experienced in amplifier design. This conversion changes the power transistor form Class C to "biased on" Class B operation. The transistor is not under warranty as we've already explained, and improper configuration can easily damage it.
PAGE 15
PA1 WARRANTY NOTICE: The PA1 kit is the only item in the entire Ramsey product line that is not covered under any warranty. Because of the variety of ways in which this kit can be constructed and mounted mechanically, we cannot offer any kit repair service. So, if this kit appears too complex for your abilities, please return it for a complete refund. The PA1 kit is designed for the advanced builder who appreciates the convenience of having all the hard-to-get parts available from one reliable source.
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PA1 2 METER RF POWER AMPLIFIER Quick Reference Page Guide Kit Building Tips ................................ Parts list ............................................ Assembly .......................................... Parts Layout Diagram ....................... Schematic Diagram .......................... Testing .............................................. Troubleshooting ................................ Transmitting-Receiving ..................... Customizing ......................................