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Signal should be heard. There will be some gain by virtue of the antenna
coil. Gans of 3 to 10 are usual in household receivers and from 10 to 50
in auto receivers. The voltage applied to the grid is in effect the
voltage ECshown in Fig. 3.
Trouble Failure of the signal to appear with normal gain at A may be caused by one or more of the following: (1) some failuer in the coil or wiring; (2) open a.v.c. condenser preventing the circuit from tuning; (3) shorted tuning condenser or trimmer; (4) leakage from grid to ground; (5) tube drawing grid current and loading the secondary. Another cause is wrong tuning. R.f. coils do not always track accurately with the dial, especially at the lower frequency end, advantage being taken of their broadness of tuning to allow for production tracking errors. |
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