‰  NOW 13 WPM  ‰   TEXT IS FROM MARCH 2015 QST  PAGE 32  ‰

ATTINY85 TO MEASURE THE FREQUENCY OF ANY VALID SIGNAL ON THE INPUT, UP TO A
MAXIMUM FREQUENCY OF AT LEAST 30 MHZ, AND IN MOST CASES, TO AS MUCH AS 60
MHZ.  THE GATE LED WILL BRIEFLY EXTINGUISH TO SHOW THE MEASUREMENT IS IN
PROGRESS.  MY VERSION IS LIMITED TO ABOUT 30 MHZ DUE TO LIMITATIONS OF THE
ELDERLY 74HC4060 CHIP I HAD IN MY BIN.  MANY NEW PARTS WILL PERFORM ABOVE
80 MHZ.  EVEN THOUGH THE ACCURACY IS ROUGHLY LIMITED TO ONE PERCENT DUE TO
THE INTERNAL RC CLOCK OSCILLATOR OF THE ATINY85 CHIP, FREQUENCIES ABOVE 100
ƒ  QST DE W1AW  ‰
KHZ ARE ANNOUNCED WITH A RESOLUTION OF THREE DIGITS, WHICH IS USEFUL FOR
TASKS LIKE CRYSTAL SORTING OR WHEN THE COUNTER IS USED WITH A DIP METER.
FREQUENCIES BETWEEN 10 KHZ AND 100 KHZ ARE ANNOUNCED WITH TWO DIGIT
RESOLUTION.  FOR EXAMPLE, AN INPUT FREQUENCY OF 3R76 MHZ WOULD BE ANNOUNCED
AS THREE POINT SEVEN SIX MEGAHERTZ.  IF THE SIGNAL LEVEL ON THE INPUT IS
TOO LOW, THE COUNTER WILL REPORT ZERO, INDICATING A LARGER INPUT LEVEL IS
‰  END OF 13 WPM TEXT  ‰  QST DE W1AW  ƒ