ARRL HB (92-94) CHP 34 FIG. 60, (88-91) CHP34 FIG.66
Description. This is a crystal calibrator project that can use either a 1MHz, 2 MHz or 4 MHz reference crystal. The frequency output of 100, 50 or 25 KHz is switch selectable. The project uses two 7474s, a 7400, and a 7490 IC.
CRYSTAL CALIBRATOR MARKER GENERATOR FOR 100, 50, 25KHZ
ARRL HB (1988 ONLY) CHP25 FIG.33
Description: This project uses a 100KHz crystal and LF353, 4001, 4013 IC's. It is switchable between the 100KHz, 50KHz and 25KHz marker positions.
ARRL HB CHP 25-30 (FEB89 QST)
This is a 1 to 40 MHz counter with 100Hz resolution with a range switch changing the prescale factor. The frequency is displayed on a four digit bubble display (DL34M) LED and is driven by a 74C926. The counter requires a TTL level input. (There is a schematic for a wideband amplifier but I do not have a board for that circuit.). A 3.579545 MHz crystal is used for the time base with a MM5369 IC osc/divider. Other IC's used in the project are (4) 4017's and a 74HC4017.
COMM QRTLY Spring98
Description: The counter uses 74AC151, PIC16c62a-10/sp and 7 common cathode 7 seven segment LEDs. Two boards in the project, the processor board and the display board each measuring 2" by 4".