Craig: You're very close (and a lot closer than I was), but it's actually a little more complicated than that. Here's a cut and paste from an FCC document at http://www.fcc.gov/eb/Orders/2003/DA-03-1033A1.html:
Section 73.44(b) of the Rules requires that the emissions of an AM station that are removed by more than 75 kHz from the carrier be attenuated at least 43 + 10 Log (Power in watts) or 80 dB below the unmodulated carrier level, whichever is the lesser attenuation. So our 1 kw station on 1450 ought to be 73 dB down, or 50 microwatts. Sounds like Dave has a goodreason to call them - there's no way they are within spec. Chuck -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Craig Healy Sent: Sunday, January 21, 2007 12:38 PM To: Mailing list for the International Radio Club of America Subject: Re: [IRCA] Local 2nd and 3rd Harmonic > My recollection is that harmonics must be down 40 dB from the carrier. > That's .1 Watt for WCTC. You didn't say how strong a signal you are > receiving - if it's very strong it's surely more than .1 Watt and deserves a > mention. If it's a wispy DX level signal, they may be within legal limits > and wouldn't appreciate a false alarm. > > If the 40 dB rule has changed since I last had to know these things, I'm > sure one of our broadcast engineers will speak up right away. The last time I had a spectrum test run at a client, I think the figure was -73db. It is measured about a kilometer away from the site. If the signal is -73db down from the fundamental, then it's good. I might be wrong on the figure, but I think it's more than 40db. What I would do on that station is make sure that the harmonics are heard at other locations. Sometimes they are locally generated by things like aluminum downspouts that have dirty of corroded junctions that form defacto diodes. Craig Healy Providence, RI _______________________________________________ IRCA mailing list [email protected] http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: [email protected] _______________________________________________ IRCA mailing list [email protected] http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: [email protected]
