MFJ Enterprises 8100w World Band Receiver Manual
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MFJ-8100 World Band Receiver 1 MFJ-8100 World Band Receiver Table of Contents For Beginners Page 2 Just a Bit of History Page 2 Back to Today and the Future Page 3 A Simplified Explanation of How it Works Page 3 For Experienced Hams, Enthusiasts and Engineers Page 4 Receiver Controls and Connections Page 6 Understanding and Using the Regeneration Control Page 7...
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MFJ-8100 World Band Receiver 2 Instruction Manual written by Dan F. Onley, K4ZRA Copyright 1993 by MFJ Enterprises, Inc. All Rights Reserved.
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MFJ-8100 World Band Receiver 3 For Beginners Youre about enjoy a versatile shortwave receiver which employs a circuit concept that is as classic as the 1920s but which uses modern engineering that takes advantage of the advanced capabilities of todays electronic components. This shortwave radio is designed to let you listen to a great variety of international broadcasts. You can choose from five different frequency bands so...
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MFJ-8100 World Band Receiver 4 receiver kits offered by the major radio companies of several decades ago. (The fondest dream BACK THEN of most of these radio builders was to be able to afford to move up to a superhet communications receiver. Their fondest memory TODAY is that very first receiver kit.) From the late 1970s through the 80s, as consumer electronics and new ham radio equipment became more sophisticated so very...
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MFJ-8100 World Band Receiver 5 To put it very simply, a detector converts radio energy from an antenna into audio energy, i.e., a sound which you can hear. A detector can be as simple as a crystal diode, which is the heart of the simple crystal radio. If youve ever heard unwanted radio signals on a stereo, telephone, PA system or intercom, you can assume that some part of those devices has acted as a detector to convert a nearby...
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MFJ-8100 World Band Receiver 6 Why use a REGENERATIVE circuit for a kit new for the 1990s? A fair question, but the MFJ-8100 is not like any regenerative HF receiver youve ever used before! Our GOAL determined the design and circuitry of this receiver. We wanted the following features: GOOD reception of BOTH shortwave AM and CW-SSB Ease of kit-construction for newcomers Reasonable price A quality look and feel...
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MFJ-8100 World Band Receiver 7 with an RF gain pot that has little effect on frequency or regeneration. __ Manageable, tame regeneration control circuit. Regeneration begins smoothly with no pop and has a comfortable adjustment range. The result, we think, is a receiver design which bridges the classic simplicity of regeneration to the performance demands of the 1990s. Heres how we did it: In brief, the circuit uses RF...
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MFJ-8100 World Band Receiver 8 To prolong useful battery life, R13 limits current draw by the LED (CR1) to minimum reasonable visibility as an on-off indicator.
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MFJ-8100 World Band Receiver 9 RECEIVER CONTROLS AND CONNECTIONS Most of the controls are self explanatory. However, it is very important to understand the correct use of the Regeneration Control and the two internal trimmer adjustments of the receiver. BANDSWITCH (SW1) This quality rotary switch selects any one of the 5 tuning ranges from A to E indicated on the tuning scale. TUNING (C1) The Tuning knob controls an...
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MFJ-8100 World Band Receiver 10 REGENERATION RANGE TRIMMER (R20) Ordinarily, this trimmer is adjusted only after kit construction or in the unlikely event that any of the FET transistors are replaced. This adjustment assures smooth regeneration over all five of the tuning ranges. See Construction Phase 5. DIAL CALIBRATION TRIMMER (C5) This one-time internal adjustment is made with a miniature screwdriver in order to...