THE Dipper

Clayton Bane, W6WB‘s, March, 1947, article, “… About Grid-Dip Oscillators,” was followed two months later by “The Dipper “(reproduced below) by Wilfred “Bill“ Scherer, W2AEF. The article offered a variation on the GDO circuit presented by W6WB, helping to build the popularity of griddip meters. But more importantly, this article represented the first time Bill Scherer’s byline appeared in the pages of CQ. It was far from the last. Bill went on to become CQ‘s Technical Director for many years, presenting easy-to-understand explanations of technical material and practical projects within both financial and skill reach of the average ham. We try to carry on that tradition today. – W2VU

SUCH INTENSE INTEREST has been displayed by every amateur who has witnessed demonstrations of several commercial models of the Dipper, designed by the writer, that it was decided to design a simple Dipper which could be easily constructed by the radio amateur.

The Dipper is, actually, the grid-dip meter which, for many years, has lain neglected on the shelf of most radio shacks. The first postwar reference in amateur literature appeared in March CQ 1. The grid-dip meter is simply an r-f oscillator with a milliam meter connected in the grid circuit to show relative grid current. When the oscillator is coupled to a resonant circuit, power is taken from the oscillator tank circuit and is so indicated by a decrease in the grid current meter reading.

The grid-dip meter, therefore, may be employed to check the resonant frequency of a circuit, without the application of power to the circuit in question, simply by loosely coupling it to the inductive portion of the circuit and tuning the to the point at which its grid meter shows a marked dip, the resonant frequency being read directly from the calibrated scale. Its use in this manner results in the saving of considerable time when coils are wound and tuned circuits set up for transmitters, receivers, wave traps, absorption-type frequency meters,