I'm in the process of building the RF signal generator described here:
http://www.vintage-radio.com/project...generator.html . The circuit is the same except for the FET. I couldn't get a BF244A so I used 2N5457 which is supposed to be an equivalent (?). My varcap is a bit larger (465 pF) so I decided to try the various inductors first individually before I hard wired them to the rotary switch. That way I could find the suitable coils to get the best frequency ranges. I didn't get past trying the first pair of inductors (2.2 mH), though. When the varcap is fully meshed I get a beautiful sine wave in the oscilloscope but when I rotate the varcap the amplitude decreases proportionally and somewhere after halfway the oscillation stops. The frequency increases as it should. Can someone suggest a solution to this problem?
Bytheway, I'm going to add a digital display to the generator if I ever get it to work. I bought a cheap kit from here:
http://www.pongrance.com/ddfc.html .
Timo