Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!ames!elroy!gryphon!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: 28 Jun 89 08:45:00 GMT Sender: news@vector.Dallas.TX.US Lines: 32 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 218, message 5 of 6 I think Aaron Heller has it right. Of course, his mention of WRPI brings back memories... I was chief engineer of WSPN in Saratoga Springs when we got the FM license (10 watts at the time) in 1974, and we were on 91.1, vs. 91.5 for WRPI. Now WRPI was the most-listened-to station on our campus at the time, so I wasn't really happy about going only 400 kHz away, but our consulting engineer noted that WRPI's protected zone (60 dB above 1 microwatt per meter, per FCC rules Part 1 if I recall) ended about 3 miles from our tower (high-rise dorm), so we could freely clobber them. Had WRPI been (legally) 2 dB stronger, they'd have prevented us from fitting in! The reason FM broadcasting sounds so good (hi-fi, relatively) is because it has a wide bandwidth. A signal is nominally 150 kHz wide. At 92 MHz, that's about .16% of the bandwidth. If you tune the transmitter sharply enough (as Aaron Heller tried), it'll indeed probably be a bit out of tune by the edges of the channel, causing the FM to have an AM component. It's slope-tuning itself. And that's of course a flagrant violation of FCC technical standards. If, just as a hypothesis, the engineering dept. decided that they "answered to a higher authority" and wanted to "spread the word" without regard for the FCC, then they'd indeed tune for "maximum smoke". BTW, under the terms of the Communications Act, licenses aren't permanent; every renewal must be weighed equally against competing renewals for the same frequency (i.e., applications for new construction specifying the existing station's frequency). This caused two of Boston's big 3 network TV stations to be reassigned! Flagrant violation of FCC standards could weigh heavily in such an application, if somebody in Chicago wanted to apply for a new station on 92.3... fred [disclaimer: opinions are mine alone; sharing requires permission, etc.]