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16 db Gain, 1 db Noise Figure
•
Runs on 9 to 15 VDC
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Hi-Q tuned input to reduce
•
overload
Small size to fit in any rig
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The most popular preamp kit in
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the USA!
Easy 15 minute assembly
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Perk up your reception on 220 MHz with this easy-to-build and install kit.
Works well with any radio - especially effective in repeaters. Rugged design
using a microwave transistor outperforms units costing triple the price!
220 MHz
LOW NOISE
PREAMP
KIT
Kit No. PR20
PR20—1
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Table of Contents
Related Manuals for Ramsey Electronics PR20
Summary of Contents for Ramsey Electronics PR20
- Page 1 Perk up your reception on 220 MHz with this easy-to-build and install kit. Works well with any radio - especially effective in repeaters. Rugged design using a microwave transistor outperforms units costing triple the price! 220 MHz LOW NOISE PREAMP Kit No. PR20 PR20—1...
- Page 2 INTRODUCTION TO THE PR20 LOW NOISE PREAMPLIFIER A “preamplifier” gives an initial boost, measured in decibels, to the level of a signal before it is further processed by tuned circuits, filters, amplifiers, mixers, detectors, or other circuit stages. Preamps may be designed for either RF or audio use and may be either tuned or broadbanded.
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Page 3: Circuit Description
R1 and R2. The actual circuit is about as simple as they come. Maximum gain and freedom from oscillation are accomplished by the quality of workmanship in parts installation and I/O connector wiring PR20—3... -
Page 4: Other Components
PARTS SUPPLIED WITH PR20 KIT CAPACITORS 2 2 or 2.2pF disc capacitor (C1,2) 1 10pF disc capacitor (C3) 1 100pF disc capacitor [marked 100 or 101] (C4) 1 .01uF disc capacitor [may be marked .01, 103, or 10nF] (C5) RESISTORS... - Page 5 RAMSEY PR20 PRE-AMP PARTS LAYOUT NOTE FOR PR-20: Disregard C6 PR20—5...
- Page 6 PR20 PRE-AMP ASSEMBLY PROCEDURE Soldering nine parts to a PC board is not a big job, but good performance of the PR20 requires attention to keeping all leads as short and neat as possible. The order of parts installation is not critical for this and other small kits, so the purpose of the following suggested order of assembly is just to make it as easy as possible for you to get the parts placed correctly on the first try.
- Page 7 8. Install C1, 2 or 2.2pF (marked 2 or 2.2). C1 is the antenna input coupling capacitor. 9. Install L1, the shielded coil. L1 fits only one way, with the three thin leads oriented toward Q1. This coil has metal mounting tabs; use plenty of heat to solder these. PR20—7...
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Page 8: Input And Output Connections
RF connectors you wish to use. For the neatest installation, it is good practice to pre-tin the coax ends before soldering to the PC board. Plan your probable applications with as much foresight as possible so that you don’t spend more on cable adapters than you did on the kit! PR20—8... -
Page 9: Testing And Adjustment
Even though this sounds like unneeded advice and common-sense knowledge, we should remember that most of today’s receivers are in transceiver configuration, and that all it takes is one accidental push of a button out of habit, or an inadvertent bump of a keyer, to destroy a preamplifier. PR20—9... - Page 10 DPDT power switch with one pole controlling voltage and the other pole connecting the input and output of the PR20 when the DC supply voltage is in the “OFF” position. This setup is very practical when you want to switch the preamp in and out of a receiver antenna line.
- Page 11 A 220 MHz “ACTIVE ANTENNA” For situations where a simple indoor receiving antenna is needed, the PR20 preamp will add considerably improved performance to a whip antenna adjusted to 1/4 or 5/8 wave. And, for a very well engineered true active antenna for both HF and VHF at a break-through low...
- Page 12 Standard replacements: ECG10 or SK9139. You may, of course, order replacement 2SC2498 transistors from the Ramsey factory in Victor, NY, but we are pleased also to give you this pipeline to your own local electronics parts dealer if 2SC2498 replacements are needed. PR20—12...
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Page 13: Troubleshooting Guide
TROUBLESHOOTING GUIDE The only possible causes for malfunction of the PR20 are faulty or incorrectly installed parts. Re-check your work. Transistor replacement information is provided. Poor performance such as oscillation can be caused by bad parts-mounting (excessive lead length of resistors or capacitors). Erratic operation will be traced to poor input, output, or voltage connections, or a faulty solder connection. - Page 14 THE RAMSEY PR2: THE ULTIMATE BROADBAND PREAMPLIFIER After you find out how practical a well-built PR20 can be for 220MHz operating, you will be quite impressed with the “all bands” higher gain (also with very low noise) plus the convenient AC power supply, BNC I/O connectors and LED ON-OFF indicator of the Ramsey PR2, available factory-wired.
- Page 15 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. 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.
- Page 16 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. Published by Ramsey Electronics, Inc. Copyright 1994 All rights reserved. Ramsey Electronics, Inc.