[TenTec] Practicing with the Orion

[Don]

After reading through the manual today and paying particular attention to "Weak Signal DX Reception, Contest Operation and the Orion" section it occurred to me that I don't know what a 3db above the noise signal threshold sounds like.  I know what I consider to be a weak signal but if you want to sit down and just practice using the filter settings it would be nice to have a reliable signal to use.  So my question is does anyone know of a (relatively) inexpensive signal generator (schematic) so that I could purchase/build one?  OR perhaps someone knows of another way to do this?

 

Thanks 

Don kd6hq