Path: utzoo!attcan!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!killer!vector!telecom-gateway From: goldstein@delni.enet.dec.com (Fred R. Goldstein dtn226-7388) Newsgroups: comp.dcom.telecom Subject: Re: Praise the Lord and Pass the RF Filters Message-ID: Date: 23 Jun 89 08:38:00 GMT Sender: news@vector.Dallas.TX.US Lines: 73 Approved: telecom-request@vector.dallas.tx.us X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@vector.dallas.tx.us X-TELECOM-Digest: volume 9, issue 211, message 7 of 7 That's a great story, but either it's a put-on, or the facts don't sound quite right. (Marvelous writing, though. Is our moderator a journalist by trade?) Had WYCA been an AM station, then it would have been perfectly believable. Indeed, "blanketing" by AM transmitters is a common problem. I grew up about 3 miles from the WABC-AM transmitter (which is in Lodi, NJ) whose 50kw 770 kHz signal had a habit of getting into everything, including the phone. People who live within blanket zones routinely pick up transmissions on everything from telephones to dental fillings. It's the "crystal set" phenomenon: Any nonlinear element will rectify the signal, "detecting" AM transmissions, whose transmitted power varies (in the time domain) in accordance with the modulation. In fact, I'm guilty of it myself. I have my ham radio antenna strung in the attic, and when I use a mere 100 watts of single-sideband on the HF shortwave bands, our telephone is clobbered. Of course, the antenna comes within 15 feet of the inside phone wire. (Sticking a "split bead" ferrite inductor on the phone wire didn't solve it, but may help a little; you can buy them at Radio Shack.) But an FM station? Not so fast. FM transmitters maintain a constant amplitude, so if you "detect" them with a simple rectifier, you won't get anything but perhaps a steady DC voltage. (It'll light a fluorescent tube, though, if you're close enough.) Telephones won't detect FM the way they detect AM. I've noticed a faint hum on phone lines caused by FM blanketing, but not the actual modulation. Perhaps WYCA is on AM too. In any case, raising the FM tower would actually lessen blanketing, since the "pancake" pattern of an FM antenna points very little signal downwards. fred (k1io) [Moderator's Note: Well.....:).....I have been 'guilty of it' myself a few times with CB radios and the like. The story was NOT a put-on. And I quite agree with your assessment that FM signals should not operate in the manner described in the story. In fact, people in North Hammond have used your same argument with the FCC: to wit, if WYCA is running so legally all the time, how *possibly* could their signal be so all pervasive, heard everywhere including via my gold fillings, etc. The answer has never been forthcoming. WYCA does *not* have an AM operation. They are strictly FM, and have been since they first went on the air about thirty years ago. I can recall as far back as the middle seventies people complaining about abuse of the airwaves by WYCA. The [Hammond Times] remarked on it occassionally a number of years ago, when the station was in its early days, and sharing studio space with WJOB, an independent AM station at 1230 kc in Hammond. This is a group of people, who in their early days, when FM receivers were not as common as they are now, told their listeners -- and I quote -- "if you don't have an FM radio, you can *still* listen to us: just turn on your television set and tune it as far above Channel 6 as you can; you will probably hear us." In those days they routinely splattered all over their frequency neighbors and could have cared less. Calls to their studio in those days got you an automatic reply: "We operate in accordance with FCC regulations. Thank you for calling. Goodbye." The trouble stopped around 1980 for several years while their antenna was still in South Hammond in the lot behind their studio on Calumet Avenue. They bought the Burnham, IL location in 1981-82 sometime, and still there was no trouble. Once the FCC got off their case a couple years ago, all of a sudden the complaints started coming in again. You tell me. I know the people in North Hammond -- at least the ones who hate WYCA -- would be eternally grateful if *someone* could convince the FCC that there were problems. When I had my little pocket size transistor radio out there, within maybe two blocks no matter *where* I tuned on the dial all I got was WYCA. There is something wrong. Fred, maybe you can intervene. I would *love* to see WYCA get their license yanked. PT]