10-02-2017, 10:42 PM
The complete frequency changer stage employing the 7S7 valve has been completed.
According to the rule of Glasnost I must report the performance of the receiver is not very good at all.
Only one strong station can be heard with sufficient volume and quality, a few other stations can be received but they are very weak. The problem is I'm sure with the aerial tuning coils. There is a distinct chance that I have wired the aerial coil incorrectly. It has three windings, long waveband, medium waveband and the aerial coupling winding.
To test the aerial circuits the 7S7 valve is removed. A crystal diode is connected to the hexode control grid valveholder tag. A 470Kohm load resistor wired in, the test meter or scope will be connected across the load resistor. A signal generator will supply 500 to 1500Khz and the various resonance points recorded on the scale. The long wave coverage will also be checked. The set must be disconnected from the mains for these test procedures.
Geordie McBoyne.
According to the rule of Glasnost I must report the performance of the receiver is not very good at all.
Only one strong station can be heard with sufficient volume and quality, a few other stations can be received but they are very weak. The problem is I'm sure with the aerial tuning coils. There is a distinct chance that I have wired the aerial coil incorrectly. It has three windings, long waveband, medium waveband and the aerial coupling winding.
To test the aerial circuits the 7S7 valve is removed. A crystal diode is connected to the hexode control grid valveholder tag. A 470Kohm load resistor wired in, the test meter or scope will be connected across the load resistor. A signal generator will supply 500 to 1500Khz and the various resonance points recorded on the scale. The long wave coverage will also be checked. The set must be disconnected from the mains for these test procedures.
Geordie McBoyne.
