[R-390] Re..Motorboating on R-390A

[Steve Hobensack]

   Randy, Since the noise is not present when the calibrate signal is on, it 
sounds like it is interference external to the receiver. The calibrate 
position just opens the antenna connection and then injects its signal. 
Switching power supplies are notorious for that type of repeating 
interference. Look for something in your home such as wallwarts, tv, vtr, 
programable thermostats,etc. I have problems of that type due to a tv cable 
power supply box 300 ft away, but its fairly weak.
   I once had oscillations generated within my R-390a. The bfo was not 
neutralized. I had all kinds of trash around 3500 kc, with and without an 
aerial.

73...Steve...N8YE