by Cor van Rij
Because some people were interested I've decided to put the schematic online. There is no explanation yet but this will follow shortly.
The first part is the regenerative receiver, with drain detector, Audio low pas filter (R4, C6+C7) and a simple common emitter transistor amplifier to boost signal. To prevent unwanted feedback the power line is filtered with R11 and C11.
The second part is a simple audio amp that is used to drive a speaker or pair of head-phones. This can be replaced by any standard audio amp that might be readily available. Since I wanted to build a compete receiver, I've decided to include it as well.
With the values given the receiver is tuned to the Medium Wave Broadcast band, 500KHz to circa 1500kHz. Last week (19 October 2004) I spend a good amoutn of listening and received easily over a dozen stations all across Europe. For your information, I live in the Hague a city near the see completely in the western part of Holland. I've received stations from Sweden (Radio Sweden), Italy (Rai Uno), Spain, Crotia (Voice of Crotia), Great Brittain (BBC1 and some others), Germany (several including Bremen Eins), etc.
The antenna is the same loop antenna as used in the previous project to build a simple crystal receiver w/o anttenna.
Have fun with it. More information will come shortly.