MFJ Enterprises MFJ-249D, Инструкция по эксплуатации

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MFJ-249D Instruction Manual HF/VHF SWR Analyzer
12
"ANTENNA"
To the MFJ-249B's
connector
All leads should be short
50 ohms
Hi - "L"
Tune the MFJ-249D's frequency until the lowest SWR is reached. This is the resonant frequency of the
load.
An external diode detector and volt meter can also be used to measure the resonant frequency of circuits.
The maximum meter reading occurs at the resonant frequency.
"ANTENNA"
To the MFJ-249B's
connector
1N34
.01 10K
50 ohm
Measure the voltage
between these points
with a Hi-Z meter
All leads should be short
Testing RF Chokes
Large RF chokes usually have frequencies where the distributed capacitance and inductance form a low
impedance series resonance. The troublesome series resonance can be detected by slowly sweeping the
frequency of the MFJ-249D over the operating range of the choke. Peaks in the voltage measured by the
RF voltmeter will identify the low impedance series-resonant frequencies.
1N34
.01
10K
Measure the voltage
between these points
with a Hi-Z meter
All leads should be short
choke
"ANTENNA"
To the MFJ-249B's
connector
Refer to the section on measuring the inductance of RF chokes.
7.0 TECHNICAL ASSISTANCE
If you have any problem with your MFJ-249D, first check the appropriate section of this manual. If the manual does
not reference your problem and the problem isn't solved by reading the manual, you may call
MFJ Technical Service
at 662-323-0549 or the MFJ Factory at 622-323-5869 . We can serve you best if you have your unit, manual, and all
pertinent information about your difficulty handy so you can answer questions the technicians may ask.
You can also send questions by mail to:
MFJ Enterprises, Inc.,
300 Industrial Park Road,
Starkville, MS 39759;
by FAX to 662-323-6551; or by e-mail to techinfo@mfjenterprises.com. Send a complete description of your
problem, an explanation of exactly how you are using your unit, and a complete description of your station.
MFJ-249D
MFJ-249D
MFJ-249D