BK Precision 1803D - 200MHz Frequency Counter

The 1803D is a value-priced frequency counter offering users a simple and accurate frequency measurement.

Note: The instrument must be powered via the included 110 V AC power adapter.
 

Considerations

Display Instability

An uncertainty of ± 1 least significant digit is inherent in all digital measurements, and greater uncertainties can result from other factors. For example, in low frequency measurements, high frequency noise on the input can cause miscounting. Also, uncertainty may be introduced by instability of the input frequency, usually common with LC-type oscillators.

Use of Antenna

To measure transmitter frequency, it is not always necessary to have a direct electrical connection to the transmitter. In fact, the counter should be protected against from excessive power levels. A preferred method of frequency measurement is to connect an antenna to the input of the counter .The BK Precision Model AT-21 Antenna Kit is ideal for use with the Model 1803D counter for measuring frequencies from 20MHz to 200MHz. The antenna should be placed parallel with the transmitting antenna and separate by a few inches. The specific distance is determined by the power level of the transmitter. Some very low power transmitters may not provide enough signal to the counter with this this method. An unmodulated carrier should be transmitted and the frequency will appear on the display of the counter.

Cable Considerations

Cable connections in RF measurements should be aimed at reducing standing waves and shunt cable capacitance, both of which can affect measurement accuracy. Standing waves can be minimized by matching impedances of signal source, cable, and termination. For example, for a 50 ohm source, use a 50 ohm cable and terminate with a 50 ohm resistive load. Both standing waves and shunt cable capacitance can be reduced by keeping cable lengths short, less than three feet (91cm).