ANYONE KNOW WHERE I CAN GET THE DIMENTIONS TO THE COILS USED ON THE HEATHKIT GD-1B GRID DIP METER? I GOT AHOLD OF ONE WITH NO COILS AND REALLY COULD USE ONES FOR ALL HF FREQUENCY'S.
ANY INFORMATION WILL BE HELPFUL, AND, WILL PURCHASE ANY DIAGRAMS IF AVAILABLE.
BRUCE JOHNSTON, W8BAJ
I have had one of those "little monsters" for over 40 years and still use it from time to time. I'll have to measure coil diameters and count turns. One, or two, of the coils have a "tap" on them. The others are just plain coils. I also have a Millen GDO which usually does a better job. But, sometimes, the old Heath will get a "dip" when the Millen will not. I still have the original box in which the coils are housed!
By the way, you can "fine tune" the frequency by squeezing the sides of the housing! Also, if you talk loud enough next to the housing the output will be FM modulated.
Here are the details for the coils for the Heath GD-1B Grid Dip Oscillator:
All forms except for the highest band are 0.75 inches in diameter and 2.25 inches long. The coils are wound starting 0.125 inches from the end of the coil form away from the GDO. There are 2 pins mounted on the outside of the coil form to make connections to the GDO. Except for the 37 - 100 MHz coil, the winding start and end on opposite sides of the coil form. In all cases, the ends of the wires go down to the pins and are soldered into them.
1.8 - 5 MHz: This one was "too fine" of a wire (about 32 - 34 gauge) for me to actually count turns. However, the winding is 0.625 inches long. You might have to experiment a little with this one (use a general coverage receiver to check the frequency).
5 - 15 MHz: 26.5 turns of #26 wire.
14 - 37 MHz: 9.5 turns of #22 wire.
37 - 100 MHz: 2.25 turns #18 wire.
100 -250 MHz: Hairpin loop made of .1875 inch diameter solid wire plus the pins to go into the GDO that is 1.625 inches long. You have to add the pins to this length of wire.
Anyway, I hope that this helps.