Frequency Counter  (220-0305)        Operation          Faxback Doc. # 6777

TURNING ON THE COUNTER

To turn on the counter, set POWER OFF/ON to ON.

SETTING THE INPUT IMPEDANCE

You can select an input impedance of 50 ohms or a high-impedance setting.
Set the input impedance switch to 50  ohms if you connected the supplied
antenna or an optional 50 ohms coaxial cable.  Set the switch to HiZ if
you connected an optional high-impedance probe, such as an oscilloscope
probe.

SETTING THE FREQUENCY RANGE

To ensure accurate measurements, set the frequency range switch to the
position that corresponds to the frequency you want to
measure.

Set the switch to DOWN to measure frequencies between 1 and 50 MHz.  Set
it to UP to measure frequencies between 50 MHz and 1.3 GHz (gigahertz).

Note:  If the measured frequency is in a range other than that indicated
       by the switch setting, the meter might give incorrect results.

SETTING THE GATE SPEED

You can select from two gate speeds: slow and fast.

The slow gate speed (the default setting) updates the display every 1.28
S.  This setting provides the maximum display resolution (least
significant digit is in units of 100 Hz).

The fast gate speed updates the display more quickly (every 128 mS) but
shows a lower resolution (least significant digit is kilohertz).

Press GATE SPEED to toggle between a fast and slow gate speed.

MEASURING FREQUENCIES

The counter's display shows all measurements in Megahertz (MHz).

After you turn on the counter and set the input impedance, frequency
range, and gate speed, do the following to measure frequencies.

If you connected an antenna, fully extend the antenna and be sure the input
impedance switch is set to 50 ohms.  Then turn on the device whose
frequency you want to measure.

For example, to check the transmission frequency of a channel on a CB
radio, turn on the CB.  Then select the desired channel and press the CB's
talk button.  The counter's display shows the channel's transmission
frequency.

If you connected an optional cable, you can measure frequencies from an
oscilloscope or other high-impedance input probe.  Be sure the input
impedance switch is set to HiZ.  Then turn on the device whose frequency
you want to measure.

Caution:  Any input signal should not exceed 1.4 V peak-to-peak.
          Measuring signals with a higher voltage could damage the
          counter.

Note:  When you do input a specific frequency, the display shows random
       frequencies.


USING THE BACKLIGHT

The counter's display has a backlight to help you see the display in low
light conditions.

To turn on the backlight, press BACK LIGHT.  The backlight stays on for
about 10 seconds.  To keep the light on for an extended period of time,
press and hold down BACK LIGHT for at least 2 seconds.  The backlight
stays on until you turn off the counter.

(LB/all-06/30/94)