24 July 2016
BUILD IT YOURSELF
This article describes a DIP meter with a
digital display, plus updated components
and increased functionality from a version I
built back in 1993. This device covers a
frequency range of 1 MHz to 56 MHz, and
can also be used as a frequency counter.
Although the display is only three digits, the
counter allows you to view six digits in two
groups of three.
DIP Meter with
By Larry Cicchinelli
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The DIP meter discussed here (Photo 1) uses a PIC microprocessor for most of its digital requirements instead of discrete logic like my original one. Several of
the ICs used in the original unit are very hard to find today.
There are two digital functions (not counting some “jelly
bean” logic) that are external to the PIC: a divide-by- 10 IC and
a tri-state buffer. The divide-by- 10 IC is used to keep the input
frequency to the PIC within its measurement range; the tri-state
buffer is used to select between the DIP meter and frequency
counter functions, as well as between the direct and the divide-by- 10 frequencies. Figure 1 is a block diagram of the circuit.
There is an excellent article on the usage and operation of
DIP meters in the February 2014 issue of QST.