Results

The project was a great success from the standpoint of AM/FM reception. I live in a large city with very strong FM broadcasts, so the FM reception was extremely clear, as can be seen in the video. In fact, the IC would pick up FM broadcasts without even needing an antenna! The antenna I used for FM reception was just a single jumper wire connected directly to the FMI (FM in) pin on the IC.

AM broadcast (530kHz-1600kHz) reception is very dependent on several factors:

1. Position of the antenna. The ferrite loop antenna is a magnetic loop antenna, acting to pick up the magnetic portion of the radiated EM wave. It has nulls in its radiation pattern in the direction parallel to the inductor (and thus ferrite rod). This means that the reception pattern is directional, with best reception occurring perpendicular to the loop.

2. Time of day. High Frequency (HF) waves have much longer wavelengths than the Very High Frequency (VHF) waves used by FM broadcasts. This allows HF waves to reflect off the ionosphere and travel great distances across the planet, but at the cost of poorer quality. AM reception is better at sunset, but also depends on the time of day at the transmitter. The farthest signal I've received with this radio came from Havana, Cuba.

3. A good ground. My radio is very poorly grounded. I live in an apartment building which did not seem to have a ground on the AC wall outlets, and my setup was too far from a good radiator or cold water pipe. Thus the RF ground is pretty poor, as it is just the common circuit ground. A better ground would result in far better reception.

4. Electrical and magnetic interference. Switching power supplies (common in virtually all appliances), interference from unshielded electronics (TV monitors, lights, etc.) all introduce noise in the lower frequencies, which greatly affects reception.