This very simple counter can be used to measure the frequency of various wireless devices. Applies in reviving the transmitter and its operation as a control monitor frequency. It can be used as a scale to the receiver. Due to the simplicity of the counter should not miss any of the equipment bastlí?e that similar facilities are still owned. Buying the parts is not a significant financial burden and required the program to the PIC is available for download. To measure the frequency of the oscillator (either the transmitter or receiver), use coaxial cable (RG58 is suitable) connected to the input port counters. At the end of the cable loop from the solder wire and place it on the oscillator coil. In some cases, the cable can be connected through a resistance of about 1 to the output amplifier stage for the oscillator.
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Display range: 0.0 to 999.9 MHz, 0.1 MHz resolution
Proper rounding the last digit blinking suppressed
Indication of alarms
Fast measurement - short measuring cycle
High input sensitivity in the VHF / UHF
Can be used as a digital scale with respect to the receiver intermediate frequency
Supply voltage: 8-20 V
Supply current: typ. 80 mA, max 120 mA
Input Sensitivity: 10 mV max in the range of 1970-1000 MHz
Measuring cycle: 0.082 to
R1 - 39 to
R2 - 1,
R3-R6 - 2.2k
R7-R14 - 220
C1, C5, C6 - 100 Mini n
C2, C3, C4 - 1 n
C7 - 100 in
C8, C9 - 22 p
IC1 - 7805
IC2 - SAB6456 ( U813BS - different connection terminals, not tested)
IC3 - PIC16F84A + programmed base
T1 - BC546B
T2-T5 - BC556B
D1, D2 - BAT41 (BAR19)
D3 - HD-M514RD (red) or HD-M512RD (green), four-digit seven-segment LED display controlled by multiplex, you can replace the individual digits
X1 - 4.000 MHz crystal
Measured from the input signal goes through a pair of Schottky diodes, which should protect the counter against high input voltage. These diodes can be omitted. Here divider IC2, which input signal is divided by 256, to be workable with other districts. After amplification is divided by the signal directly into the processor IC3, the program performs all the remaining functions. The display is controlled by the multiplex, a rapid switching between numbers. Due to the lack of outlets IC3 is...
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