2 METER RF POWER AMPLIFIER KIT Ramsey Electronics Model No. PA1 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!" · · · · · · · · · · 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! PA-1 · 1 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 Sequential Video Switcher · WCT20 Cable Wizard Cable Tracer · MD3 Microwave Motion Detector · ML Music Lights Kit · LC1 Inductance-Capacitance Meter RAMSEY AMATEUR RADIO KITS · HR Series HF All Mode Receivers · QRP Series HF CW Transmitters · CW7 CW Keyer · 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. PA1 2 METER RF POWER AMPLIFIER KIT INSTRUCTION MANUAL Ramsey Electronics publication No. PA1 Revision 1.1 First printing: December 1994 COPYRIGHT 1994 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. Printed in the United States of America. PA-1 · 2 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 .................... Customizing ..................................... Installation ........................................ Operating Your PA1 ......................... Warranty........................................... 5 5 6 6 7 11 11 12 13 13 13 15 RAMSEY ELECTRONICS, INC. 590 Fishers Station Drive Victor, New York 14564 Phone (585) 924-4560 Fax (585) 924-4555 www.ramseykits.com PA-1 · 3 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. BEFORE you begin building your PA1, we ask you to read the warranty information on page 14 and think about a few details in advance: The PA1 is a true "Ham Radio" kit project which presumes the expertise that goes along with your license. You need to know how to "tack solder", wind simple VHF coils per our directions, and how to finish your PA1 with suitable enclosure, connectors, T-R switching and I/O wiring. The Ramsey RFS1 RF-sensing T-R switch kit is available as an easy companion kit for the PA1. The Ramsey PR10 Low Noise Pre-amplifier Kit can be worked into your final T-R installation to boost those hard-to-copy signals. We ask you to understand that the VHF Power Transistor that is the heart and soul of this circuit cannot be guaranteed beyond careful tests by BOTH the manufacturer and our technicians. Because this expensive transistor can be damaged by either incorrect soldering OR incorrect physical mounting, there can be NO warranty on this part unless your own additional test BEFORE ANY soldering and mounting shows a clear defect. Use of a VHF power output wattmeter is essential to correct adjustment of the PA1. If you decide, before beginning any assembly of your PA1 kit, that this project is not quite what you're ready for, you may return the complete, unassembled PA1 kit to the Ramsey factory. OR, if you are ready to join the thousands of hams world-wide who enjoy the PA1 as the most economical possible HT improvement for the highly-popular 2 Meter band, we will be happy to guide you through every construction step in the spirit of the "Learn-As-You-Build" philosophy for all Ramsey Kit manuals for the new millenium. PA-1 · 4 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. Electrical part installation - when parts are installed, the part is placed flat to the board, and the leads are bent on the backside of the board to prevent the part from falling out before soldering. The part is then soldered securely to the board, and the remaining lead length is then clipped off. PA1 PARTS LIST: 1 1 1 1 1 1 2 2 2 1 PA1 Printed circuit board BLW40 or SD1272 RF Power Transistor Length of pre-tinned #18 wire (for L1,L2) Length of #18 enameled wire (for L3) Length of #24 wire (for winding 6 hole RF choke ferrite bead) 6 hole RF Choke ferrite bead (black cylinder) (to be hand-wound) 100 pf mica compression trimmers (rectangle shaped) (C1,C3) 60 pf variable trimmer capacitors (round shaped) (C2,C4) 47 or 56 pf ceramic disc capacitors (C5,C6) .01uf ceramic disc capacitor (marked .01 or 103 or 10 nf) (C7) PA-1 · 5 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. A smooth build-up of solder thickness is fine and will make parts installation even easier. 3. The power transistor will be installed as a later step. Right now, simply position it in place and observe how far its flat leads extend toward the input and output pads. Scribe a line into the tinned pads at each end of these two leads as a guide to the amount of pad space required by the transistor. NOTICE THE ORIENTATION OF THE TRANSISTOR'S COLLECTOR LEAD! Set the transistor aside for now, safely. 4. In installing the coils leading in and out of the transistor's pads, the idea is to stay on the other side of your marks, so that the transistor can be installed flat and neatly on the board. 5a. Examine C1, one of the mica compression trimmers. Neatly re-form the two outer tabs at right angles so they form "feet" which permit the trimmer to sit level in its correct position. Make sure the inner pins do not touch the PC board. PA1 PARTS LAYOUT DIAGRAM PA-1 · 6 PA-1 · 7 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. Now that you are accustomed to how easy good tack-soldering can be, and you can see some finished work on your PC board, this is a good time to begin making and installing the three coils and RF Choke. 9a. Cut a 1" length of #18 tinned bare wire and form it as shown, making a gentle loop around a tool handle. 9b. Install L1 using a pair of needle-nose pliers to hold it as you solder it in place. Let one end cool before soldering the other. L1 from 1"inch of bare wire 10a. Use another length of #18 tinned bare wire to make a 1-turn 1/4"-diameter coil. Spread the turn itself to 1/4" and trim the leads to approximately 1/4". Bend the ends as needed so that the coil sits in position as shown on the board. 10b. Install L2 the same way as you did with L1 in step 9b. L2 side view L2 top PA-1 · 8 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. It is easily made by passing or "lacing" 5 turns of the #24 bare wire through its holes. This will fill 5 holes with a lead coming out at each end. (Note that trying to fill the 6th hole would cause both wire ends to come out of the same end of the ferrite bead.) Trim the ends to 1/4" and bend as needed for neat installation. RFC 1 12b. Install the RF choke. 13. Install bypass capacitor C7, .01 uf (marked .01 or 103 or 10 nf) from the DC voltage pad to the ground plane. VERY IMPORTANT: PLEASE READ! The RF Power Transistor MUST be mounted to its heatsink (usually the metal case enclosure) B-E-F-O-R-E it is soldered to the circuit board. This is necessary for the sake of your investment as well as the health of the transistor. It is VERY easy to crack the transistor's case and break off the leads if you attempt to tighten the nut AFTER soldering. As has been explained, Ramsey Electronics' warranty on this transistor covers ONLY fresh, nonsoldered units which prove to be electrically defective before any installation attempt. So...NOW is the time to decide how you are going to enclose your PA1. If that decision is still to come and you wish to experiment with the performance of the PA1 before designing a finished accessory such a "docking booster", then PA-1 · 9 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. After reviewing the mounting information, mount Q1 to its heatsink or section of metal enclosure. 16. After double-checking the orientation of the collector lead, solder all four Q1 connections. 17a. The final circuit-wiring steps consist of the CORRECT installation of two small 47 or 56 pf disc capacitors. This step is more critical than many builders may realize, because excess lead-length of C5 and C6 will reduce power output and induce feedback! The bodies of C5 and C6 should fit snug against Q1 and you should see little or no capacitor wire lead at all! 17b. Install C5 in accord with 17a. 17c. Install C6, just like C5. FINAL PC BOARD WIRING BEFORE TESTING: 18. Solder the 12-volt DC power line connections. 19a. Use good-quality coax terminated to fittings for your own application. 19b. Install coaxial input and output lines. Take a moment now to review your work. Touch up any solder joints that need to look smoother and shinier. This effort can actually improve performance as well as make you proud of your work and enhance the resale value of your amplifier. There should be NO evidence of excessive wire length or roughlooking solder joints. PA-1 · 10 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 v ...