Posted by David Saviet on November 06, 2009 at 06:22:07:
In Reply to: Re: Re: Re: Re: Get Your News Seven Seconds Faster At NewsRadio 450.5125 MHz posted by Mike Seaver on November 05, 2009 at 10:56:57:
The reason you used to hear a whistle on radio stations operating at 910 Khz was due to the 455 Khz IF, which was common in older radios. 910 is the second harmonic of 455 and while the transmitters were crystal controled and when operating properly, very stable, tube radios were not.