I'd like to build a simple AM receiver for 25 and/or 28 MHz to receive DCF77-formatted time code. It doesn't have to be extremely sensitive or selective - the local clock oscillator will keep time while it cannot receive the time code during my rare HF transmitting activities. Frequency stability should be relatively good (crystal controlled). Could anyone suggest a basic schematic or kit for the purpose?
There's a local 25.000 MHz reference transmitter which has good local coverage, and I'd like to receive that. In addition I'd like to build a version for 28 MHz to receive a local amateur beacon and my own testing transmissions.
Please not that this is not the DCF77 station (77.5 kHz) in Germany, this is a local reference transmitter on 25 MHz which just happens to use the same time code format.
I'd prefer a traditional standalone receiver (one that doesn't require a computer for SDR), since I'd like to decode the time code in a low-power Atmel microcontroller.