MFJ MFJ-259 Скачать руководство пользователя страница 15 | Manualshive

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MFJ MFJ-259 Скачать руководство пользователя страница 15

MFJ-259 Instruction Manual

HF/VHF SWR Analyzer

14

C(pF) =

1

00003948F L

F = MHz L = H

2

.

µ

Measure inductance

1.

Connect an unknown inductor with the highest value standard capacitor in series.

2.

Connect the series LC circuit to "ANTENNA" connector with a 50

Ω

resistor in series.

3.

Adjust the tune knob through the bands until you get the lowest SWR. If you do not get a

deep meter deflection change to the next smaller value standard capacitor and try again.
Repeat the process until you get low SWR.

4.

Solve this equation using F as the resonant frequency and C as the capacitance of the

standard capacitor.

L( H) =

1

00003948F C

F = MHz C = pF

2

µ

.

RESONANT FREQUENCY OF TUNED CIRCUITS

The MFJ-259 can be used to measure the resonant frequency of tuned circuits by two
methods. The first method involves placing a 50 ohm resistor in series with the MFJ-259
"ANTENNA" connector. The MFJ-259 connects through the resistor to the parallel tuned
circuit. This circuit is for high capacitance values.

Tune the MFJ-259's frequency until the "SWR" meter reaches the highest SWR. This is the
resonant frequency of the load.

"ANTENNA"

To the MFJ-259's

connector

All leads should be short

50 ohms

Hi - "C

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Содержание MFJ-259

Страница 1: ...Finding a Short Circuit in Coax Cables 8 Testing and Tuning Stubs and Transmission Lines 8 Velocity Factor of Transmission Lines 9 Impedance of Transmission Lines 10 Estimating transmission line loss...

Страница 2: ...Hz 26 2 62 5 MHz 62 5 113 MHz 113 170 MHz The MFJ 259 can be used to adjust or measure the following Antennas SWR resonant frequency bandwidth efficiency Antenna tuners SWR frequency Amplifiers Input...

Страница 3: ...lts BATTERY INSTALLATION If batteries are used they must be installed by removing the 8 Phillips head screws on each side of the case The eight batteries fit in two separate battery holders with the p...

Страница 4: ...g of 1 1 The common misconception that 25 ohms of reactance and 25 ohms of resistance in a load will give a 1 1 SWR is absolutely untrue The actual SWR in this condition will be measured as 2 6 1 The...

Страница 5: ...evice under test WARNING Never apply power to the ANTENNA connector To measure the SWR of a 50 ohm coaxial line simply connect the line to the ANTENNA connector The counter input should be set to A Pr...

Страница 6: ...ter The frequency counter in the MFJ 259 will typically measure frequencies between a few hertz and 200 MHz At frequencies above 1 MHz the frequency counter is sensitive to 600 mV Below 1 MHz the coun...

Страница 7: ...for a lossy cable Hard line is not usable since there is no leakage The leakage from the cable is usable under normal conditions for a low level counter input Experimentation will be needed to determi...

Страница 8: ...turers down play the importance of good radial systems with grounded verticals If you have a good ground system the SWR of a quarter wave vertical can be nearly 2 to one The SWR generally gets BETTER...

Страница 9: ...FJ 259 input 2 Turn on the MFJ 259 and start sweeping the frequency starting at the low frequency end of its range Watch the RESISTANCE METER for a dip reading and record the frequency for zero ohms 3...

Страница 10: ...ncy Velocity Factor of Transmission Lines The MFJ 259 can accurately determine the velocity factor of any impedance transmission line Measure the velocity factor with the following procedure 1 Disconn...

Страница 11: ...nd of the FREQUENCY range selected 5 Adjust the potentiometer until the SWR reading varies as little as possible over the TUNE range Note that the value of the SWR is not important Only the change in...

Страница 12: ...alls on a calibration mark At 60MHZ the meter reads 3 1 SWR Using the chart you know that the loss is 3 dB Since 28MHz is about half of 60MHz you can multiply 3dB by 7 which gives a loss of about 2dB...

Страница 13: ...ork with the tube in an operating condition with the low level of RF from the MFJ 259 TESTING RF TRANSFORMERS RF transformers that are designed with a 50 ohm winding can be easily and accurately teste...

Страница 14: ...andard value capacitors and inductors These should be collected and tested for accuracy MFJ suggests the following sets of values Inductors 330 H 56 H 5 6 H 47 H Capacitors 10 pF 150 pF 1000 pF 3300 p...

Страница 15: ...ow SWR 4 Solve this equation using F as the resonant frequency and C as the capacitance of the standard capacitor L H 1 00003948F C F MHz C pF 2 RESONANT FREQUENCY OF TUNED CIRCUITS The MFJ 259 can be...

Страница 16: ...ermining the resonant frequency is by using a small three or four link coil to magnetically couple to a tuned circuit for testing The coil should be wound around the inductor in the tuned circuit This...

Страница 17: ...ramic 50v 20 22 pF 200 0018 C11 C13 C14 C16 C19 Capacitor Disc Ceramic 25 50v 20 01 F 200 0004 C17 C18 C24 Capacitor Disc Ceramic 50 100v 20 1 F 200 0005 C2 C3 C4 C15 C6 C7 C8 Capacitor Disc Ceramic 2...

Страница 18: ...Q4 Transistor FET To 92 Siliconix J310 305 6310 Q3 Transistor FET Switching VN10KM 305 6005 Q5 Transistor HF Wide Band To 39 NPN 2N5109 305 0017 R1 Resistor 1 4 Watt 5 Film 18 Ohm 100 1180 R10 Resist...

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