User manual MFJ 269 SWR

[. . . ] MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer MFJ-269 SWR HF/VHF ANALYZER TABLE OF CONTENTS Warning: READ SECTION 2. 0 BEFORE ATTEMPTING TO USE THIS PRODUCT! INTRODUCTION 1. 0 DESCRIPTION MFJ-269 SWR HF/VHF ANALYZER TABLE OF CONTENTS Warning: READ SECTION 2. 0 BEFORE ATTEMPING TO USE THIS PRODUCT 1. 0 INTRODUCTION DESCRIPTION 1. 1 Typical Uses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1. 2 Frequency Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. 3 A Quick Word About Accuracy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. 2. 0 POWER SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. 1 External Power Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. 2 Using Internal Batteries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. 2 Using Rechargeable AA Type Batteries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. 4 Using conventional AADrycell Batteries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. 2. 5 Blinking "VOLTAGE LOW" display warning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2. 6 "Power Saving Mode" (Sleep mode). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. 0 MAIN MENU AND DISPLAY . . . . . . . . . . . [. . . ] Impedance (Z) is still described as the length (magnitude) of a line representing the complex impedance. (This is the same Z as given in other functions. ) Besides Z, an angle between zero and 90 degrees is shown. This angle represents the phase difference between current and voltage at the terminals of the analyzer. When a reactance is present, voltage and current are no longer in phase (or exactly out-of-phase) and so the phase angle increases from 0 degrees to a maximum angle of 90 degrees. The angle becomes 90 degrees when the load is a pure reactance, and zero degrees when the load is a pure resistance. 20 MFJ-269 Instruction Manual HF/VHF/UHF SWR Analyzer This analyzer will determine the angle in degrees, but it will not describe the load reactance specifically as either capacitive or inductive. It is a simple matter to determine the direction by adding a small amount of reactance in series with the load and watching the angle change. If the angle decreases, the load reactance is opposite to the sign or type of test reactance. If the angle increases, the load reactance is the same sign as the added reactance. 5. 4. 1. 2 Series Equivalent Impedance This "ADVANCED 1" display sub-mode is reached by pressing the GATE button once while in the "Magnitude and Phase of Load Impedance" mode. This mode displays the series equivalent impedance of the load. This is the most common form used to describe antenna system impedance. In this mode, the load impedance is described as a resistance in series with a reactance. In order to cancel the reactance without changing the resistance, a reactance of the opposite type and same reactance value must be connected in series with the load at the point of measurement. The digital display shows SWR, resistive part of load impedance (Rs=), and reactive part of load impedance (Xs=). The IMPEDANCE meter displays the impedance (Z in ohms) while the SWR meter displays 50 ohm referenced SWR. Series equivalent impedance display examples: 1 4 . 0 9 5 M H z > 3 1 7 . 1 5 9 8 M H z 3 . 2 R s(Z> 1 5 0 0 ) s W R s= 5 0 X s= 6 2 s W R R With impedances in the above left-hand display, resistance would remain 50 ohms, reactance would go to zero, and SWR to 1:1 if an opposite-sign reactance of 62 ohms was connected in series with the feedline at the point where the measurement was made. Note: Every series impedance has a parallel equivalent counterpart. A series impedance of Rs 50 Xs 62 is equal to the parallel equivalent impedance of Rp 126 Xp 102 ohms. This analyzer can make that conversion in this mode by pressing the GATE button. See 5. 4. 1. 3 5. 4. 1. 3 Parallel Equivalent Impedance Pressing the GATE button twice from the Magnitude and Phase of Load Impedance mode toggles the analyzer into a parallel equivalent impedance sub-mode. Parallel equivalent display examples: 7 . 1 5 9 8 M H z 3 . 2 R s= 1 2 6 X s= 1 0 2 s W R 1 4 . 0 9 5 M H z > 3 1 R s(Z> 1 5 0 0 ) s W R In the left hand display example, the equivalent parallel resistance is R=126 ohms. That resistance appears to be in parallel with 102 ohms. If we parallel connect an opposite-sign reactance of 102 ohms, the parallel equivalent reactance is canceled. [. . . ] It has the highest power capability and lowest loss for given materials. It should show a low SWR over the entire operating range of the balun with the clip lead in any of the three positions. A well designed voltage balun should show a low SWR over the entire operating range when the clip lead is in position "B". That SWR should not change when the clip lead is removed. [. . . ]