A Selection of Grid Dip Meters

Heathkit GD-1u

Cossor 1461

Tech TE-15

The Heathkit GD-1u Grid Dip Meter

I first used one of these extremely useful testers when I was building 2-meter receivers and transmitters back in the early 1960s. It belonged to G3PAC a fellow member of the Liverpool University Amateur Radio Society, G3OUL. Below is an example I bought a few years ago. There are four plug-in coils for HF and low VHF bands and a metal jumper for upper VHF. The coils cover:- Band A 1.8 to 5.4Mc/s; Band B 5 to 14Mc/s; Band C 14 to 36Mc/s; Band D 36 to 95Mc/s and Band E 100 to 250Mc/s It works as either a grid-dip meter (OSC) or as an absorption wavemeter (DIODE).

Below is the circuit diagram which shows a B7G-based EC92 connected as a Colpitts Oscillator. Hand capacity is obviated by using a differential tuning capacitor with a grounded rotor.

I bought a modern Japanese equivalent (shown at the bottom of this page) using a transistor powered by a 9-volt battery which performed almost as well as the Heathkit model, but lacked the solidity of the GD-1u and was forever being left switched on and flattening the battery.

Cossor Wavemeter Model 1461

Similar in spec to the Heathkit, this Cossor covers:- A 1.3Mc/s-3.5Mc/s; B 3Mc/s to 7Mc/s; C 6Mc/s to 15Mc/s; D 13Mc/s to 30Mc/s; E 30Mc/s to 70Mc/s; F 50Mc/s to 120Mc/s and G 115Mc/s to 300Mc/s The small polystyrene plug-in is used to measure a small value capacitor of 10pF to 50pF.

Tech Tradiper TE-15

Below is the grid dip meter I used for decades. The low frequency coil has long since disappeared.. must make a new one.

It has the following ranges:- A 440KC/s-1.3Mc/s; B 1.3Mc/s to 4Mc/s; C 4Mc/s to 14Mc/s; D 14Mc/s to 40Mc/s; E 40Mc/s to 110Mc/s and F 120Mc/s to 280Mc/s I added a modulator operated by the toggle switch above the meter. I found two different circuits of the TE-15, of which that below looks more likely, but sometime I'll open it and see which is correct...

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