Home - Techniek - Electronica - Radiotechniek - Radio amateur bladen - QST - Grid-dip oscillator calibration at V.H.F.
Some of the wide-range g.d.o.s fall off in accuracy at v.h.f. and can vary quite a few megacycles in the 144 and 220 Mc bands. One method to calibrate the g.d.o. at these frequencies is to place it a few feet away from a TV receiver and tune it until it zero beats the sound portion of the program. The table below shows the sound carrier frequencies of the v.h.f. channels. To prevent erroneous calibration due to images, move the g.d.o. as far as possible from the TV receiver to eliminate any weak false signals. The intervals between channels can be filled in by interpolation using the original g.d.o. dial markings. In the 88 to 108 Mc range, the same procedure can be used with an f.m. tuner as a receiver.
| Channel No. | Sound Carrier (Mc) |
|---|---|
| 2 | 59.75 |
| 3 | 65.75 |
| 4 | 71.75 |
| 5 | 81.75 |
| 6 | 87.75 |
| 7 | 179.75 |
| 8 | 185.75 |
| 9 | 191.75 |
| 10 | 197.75 |
| 11 | 203.75 |
| 12 | 209.75 |
| 13 | 213.75 |
Samuel M. Bases, K2IUV.