This low noise preamplifier has a gain of 19 dB in the 30 MHz band. The circuit is from the 80s. Transistors are from the era, and equivalents can be used. The circuit consumption is 13 mA.
For the 7 to 10 MHz band L1 is formed by 3 turns of 22 to 28 AWG wire in a ferrite core 15 to 20...
We found this interesting timer circuit or CMOS timer in a 1988 publication. The circuit is still...
This audio mixer was found in an old American documentation. The potentiometers are 1M and the...