Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site biomed.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!whuxlm!harpo!decvax!genrad!panda!talcott!wjh12!biomed!lagasse From: lagasse@biomed.UUCP (Robert C. Lagasse) Newsgroups: net.ham-radio Subject: Commercial FM "tweedle" Message-ID: <85@biomed.UUCP> Date: Wed, 3-Jul-85 10:08:31 EDT Article-I.D.: biomed.85 Posted: Wed Jul 3 10:08:31 1985 Date-Received: Fri, 5-Jul-85 06:19:46 EDT Organization: Mass. Gen. Hosp. - Dept. Biomed. Engineering Lines: 11 Living around Boston, I have heard several walkie-talkies that the transit police carry and also the EMS ambulance people. They all seem to be Motorolas. Anyway, it seems that when the base station releases its mike key, a couple of single tones are transmitted, very rapidly, one after another, each about 100mS long, with no space in between them, the first tone higher in freq than the other. One is about 1.5kHz and the other a bit lower, maybe around 1kHz. WHAT are these for? All comments appreciated. N 1 A L G Bobby L.