Schematics
The following schematics have been contributed by Sam, KO6JQ.
Schematic for a Pre amp Here is a schematic of a simple radio preamplifier that would help in the older tube type receivers. This is good from 10 kHz to Over 900 MHz.
Simple Short-wave Pre selector Here is a Simple Short-wave Pre selector or Antenna Tuner that will work great on most of the newer Short-wave Receivers and even for the older ones. It uses the following parts:
- A 365 picofarad Variable Tuning Capacitor
- A single Pole double pole Switch
- A Single Pole 6 throw switch
- 2 so-299 Connectors ( coax type)
The following type Molded Chokes can be found at Mouser Electronics.
- a .5 Mila henry choke
- a 3.3 Micro henry choke
- a 2.2 Micro henry choke
- a 1.0 Micro henry choke
- a 0.47 Micro henry choke
This will tune from 110 kHz to over 30 MHz
- Band 1 (the 2.5 Mila henry) from 11 kHz to 700 kHz
- Band 2 (the 3.3) from about 650 kHz to 4.5 MHz
- Band 3 (the 2.2) from about 4 MHz to 11 MHz
- Band 4 (the 1.0) from about 8 MHz to about 17 MHz
- Band 5 (the 0.47 from about 15 to about 32 MHz
Band 5 is bypass or direct to the wire; the other switch will ground the entire tuner or run.
Receive Antenna Switch A few connectors, 6 Coax types & 2 Binding Posts and a Double Pole 4 throw Slide switch.
Active Antenna Here is a simple, easy to build active antenna. It uses an 18 to 24 inch whip, and a 48 to 54 inch whip built in a metal enclosure and fed with cable type coax with f type connectors. You can run for a month off of a 9 volt battery. It will improve reception for apartment dweller's by just placing it near a window.