This circuit was found in an ancient American documentation. With it is possible to double the frequency of a transmitter For the range of 6 meters obtaining 8 W. The circuit makes use of varicap.
Using a 4046 PLL this circuit generates rectangular signals in three wavebands that depend on the...
The configuration shown was found in an old Poptronics but can be easily assembled using a common...
This circuit, found in a 1977 documentation, indicates when the grid voltage goes through zero....