From: utzoo!decvax!harpo!eagle!mhuxt!mhuxj!mhuxi!aluxz!ltn Newsgroups: net.auto Title: Re: BAD radar detectors Article-I.D.: aluxz.1114 Posted: Sat Feb 26 17:03:52 1983 Received: Sun Feb 27 03:28:12 1983 References: genradbo.1547 Just a few comments regarding superhet detectors, etc.: I don't know what sort of i.f. frequency (difference between the incoming radar signal and the internally-generated local oscillator signal) is used in radar detectors, but it can't be too high (~< 200 MHz, maybe), so if the unit is operating at 10.5 GHz, it would take a *very* good filter to stop the local oscillator from leaking out. Such a filter would cost much more than the Escort. The real way to prevent local oscillator leakage is to use a properly designed mixer, which simply doesn't send much energy back into the antenna. It's quite possible that those cheap, leaky radar detectors are in fact superhet units, but they simply have scrimped on the mixer in order to save money, and decided to let the buyer worry about the radiated signal. (By the way marc, TV's don't really use a second mixer to get down to the video frequency, but simply a.m. detect the i.f. to pull out the 4.5 MHz bandwidth video.) Les Niles (aluxz!ltn)