James Cunningham regularly published booklets of radio instructions, schematics and station plans, intended to help missionaries set up gospel radio stations.
Titles included Low Power Radio Broadcasting and The Big Antenna Book
At one point in time, James also manufactured and sold transmitters, carrier current load tuners and other assorted sundry hardware items.
One surviving document tells the story of the Cunningham Transmitters Model CM 30 - 50, an AM transmitter manufactured for export.
The low power AM transmitter schematics to the right all come from Low Power Radio Broadcasting, Missionary Edition.
- Information about the 100 mW transmitter is found on page 14
- Information about the 10 watt AM unit is listed on page 37
- Information about the 3-12 watt AM tube transmitter is on page 28
- Antenna tuning tips are on page 15
- Carrier Current Couplers are featured on page 30
Many of the left menu links still connect to archived copies of other projects and information. For example the two-part series titled "Solving broadcast problems" discusses how to deal with the kinds of RF / audio chain problems common to low power broadcasting efforts.
You'll find lots of interesting articles and comment on topics like carrier current, antenna tuning and general low power radio information.