Negative Resistance Method in Designing Oscillator

Hi,

Usually when designing Rf and Microwave oscillator, negative resistance is used.

I want to know is it possible to design a low frequency oscillator eg. 1MHz using negative resistance topology?

Yes; Google "oscillations and regenerative amplification using negative resistance devices" and you will find a good paper that includes a -R audio oscillator.

And here is a practical application of the principle at HF;

http://groups.yahoo.com/group/N2PK-VNA/files/VK6APH/