MFJ MFJ-888 User Manual
MFJ-888
Frequency Counter
Instruction Manual
Introduction
The MFJ-888 frequency counter is a compact, pocket sized test instrument, designed
for
ease of use and dependable performance. This manual is intended to help these who
have never used a frequency counter get started as quickly as possible. For these
users familiar with test and measurement equipment, complete specifications and a
detailed description of operation controls is included.
Features
• 50 ohm input for range I MHz to 3 GHz coverage.
1 Meg ohm input for range 10 Hz to 50 MHz.
• High Speed 300 MHz direct count with 0.1 Hz per second resolution.
• 10 digit LCD display.
• Ultra sensitive synchronous detector 16 section bar graph of RF signal strength.
• Hi-Z low range:
• Measures frequency and period.
• LED Backlight
• Beeper.
• Low power consumption 6-hour NiCd battery operation.
• Low battery indicator.
• Automatic held.
• Held switch locks display.
• 4 selectable gate speeds.
• Supplied with telescoping whip antenna and AC wall adapter.
SPECIFICATIONS
Input Sensitivity (Typical)
Amplifier I Meg Ohm 50 ohm
Impedance I Meg Ohm, 30 pF 50 ohm, VSWR<2:1
Range 10 Hz - 50 MHz 1 MHz- 3 GHz
_
Sensitivity
Maximum Input 100 Vans 15 dBm
Frequency Display Resolution I.
Range Gate Time LCD Sample Display
300 MHz 0.0625 Sec 10 Hz 300.00000 MHz
0.25 See I z 300.000000 MHz
I Sec I Hz 300.000000 MHz
4 Sec 0.1 Hz 300.000000 MHz
3 GHz 0.0625 Sec 1000 Hz 3000.000 MHz
0.25 Sec 100 Hz 3000.0000 MHz
I Sec 10 Hz 3000.00000 MHz
4 Sec 10 1 1z 3000.00000 MHz
<10 mV a 10 Hz- 10 MHz
<20 mV @ 10 MHz- 50 MH
<0.8 mV @u 100 MHz
<7 mV @..3D0 MHz.
<6 mV u. I GHz
<I00mV@2.4GIIz
,
RF Signal Strength Bargraph
Cabinet:
Stamped aluminum with black anod
ized finish.
AMP SWITCH
frequencies
Frequency Ist Segment Full Scale
27 MHz
150 MHz
800 MHz
Display: 10 digit Liquid Crystal Display.
Size: 3.15" H X 2.7" W X 1.22" D
Weight: 250g
Battery: Internal 4 AA 600 mAH NiCd battery pack.
Power: 9 VDC, 300 mA wall plug adapter.
Time-base:
<I
PPM typical at room temp.
7 mV
5 mV
10 mV
100 mV
90 mV
200 mV
CONTROLS
POWER SWITCH
This slide switch turns on power to the counter and initiates a 2.0 second test of all
LCD segments.
This slide switch selects either the I Meg ohm high impedance amplifier or 50 ohm
amplifier.
RANGE SWITCH
This slide switch selects the frequency range to count. Select 300 MHz for
between 1 MHz and 300 MHz. Select 3 GHz for frequencies between 10 MHz and 3
GHz. When the range switch is in the 3 GHz position, the prescaler will be activated and
"Prescale" will appear on the LCD.
LITE SWITCH , .
This slide switch turns the LCD back light on and off.
FUNCTION BUTTON
This button selects the measurement mode of frequency or period. This button has four
settings. The four modes of operation are Frequency Display, Period Display, Frequency
Display with automatic HOLD, and Period Display with automatic hold.
HOLD BUTTON
This button will stop the counter from counting and keep the current display
unchanged.
GATE BUTTON
This button selects the gate or measuring time. A longer gate means counting for a
longer period and results in more digits displayed. The four gate speeds are 0.0625 sec,
0.25 sec, I sec, and 4 sec.
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