I have a question I hope that the Broadcast Engineers on this forum can help me understand. Where I live, we have a local Class D AM station that also has a Low Power FM translator. From what I've viewed on the fcc.gov website for this station, I can only find authorizations for this radio station to operate 5kW "daytime-only" with a DA (directional antenna). I read that Class D AMs can be authorized to operate at night with a power less than 0.250kW. I guess my question is: just by virtue of being a "Class D" AM, does this automatically give the station the right to operate at low power (less than 0.250kW) at night or is an authorization from the FCC still required to operate night-time at low power? The frequency of this station is shared with a well-known 50kW Clear Channel AM. I witness many nights this station operating well past 9:00 pm on this AM frequency. The local sunset time listed on the FCC's website for this station for the current month is 5:15 PM. I'd appreciate any guidance/information you could provide. I purposely did not list the stations identification until I understood the FCC rules for this class of station. Thank you.
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Class D AM operating well into the Evening hours.
- Thread starter jonsmth62
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Night authorization is not automatic for Class D AM stations. The power and directional pattern must be approved and authorized by the Commission.
It is however not uncommon for daytime-only AMs to cheat.
It is however not uncommon for daytime-only AMs to cheat.
PTBoardOp94, thank you for your response. That is what I thought, but having been out of Radio for many years, I wasn't sure what the FCC rules were today for this class of station.
Thank you.
The FCC is strict on power and patterns. One can look up a station by call letters at the FCC website. Google FCC AM Query.
As a former manager of an AM daytimer, I discovered the hard way that a few times a year the timer would lose it's memory for no reason or change it's power down time. It always happened at changes of time (daylight savings time and back to standard time for example) but worked flawlessly for months on end. If you can give the station a call, they really might appreciate it. They might have a few watts of nighttime power or post sunset power (up until 2 hours past sunset). With a translator, it is likely the FM has far better coverage anyway (and can be on 24/7 even if the AM shuts down at sunset). It could very well be there is no local warm body to check things and a contract engineer that has a dozen other stations that doesn't bother to check.
As a former manager of an AM daytimer, I discovered the hard way that a few times a year the timer would lose it's memory for no reason or change it's power down time. It always happened at changes of time (daylight savings time and back to standard time for example) but worked flawlessly for months on end. If you can give the station a call, they really might appreciate it. They might have a few watts of nighttime power or post sunset power (up until 2 hours past sunset). With a translator, it is likely the FM has far better coverage anyway (and can be on 24/7 even if the AM shuts down at sunset). It could very well be there is no local warm body to check things and a contract engineer that has a dozen other stations that doesn't bother to check.
b-turner, I appreciate your response. I did view the data files for this station on fcc.gov using AM Query and could not find any authorizations for night-time operations. I do plan on corresponding with the station to bring up the observations I've made. I certainly don't want to throw them under the bus. As you mentioned in your post, the Engineer may not be aware that the station isn't signing off at the correct time. This is a rather small market and the conglomerate that owns this station has a few other stations in this market as way as the adjacent markets. Thank you again, for your response.
What difference does it make? If the co-channel station complains to the offending station due to nighttime interference, then that's their prerogative. As B-Turner already mentioned, sometimes there's a technical reason the station doesn't switch patterns or reduce power. It isn't unusual, nor some sort of intentional scandal by the offending station.
Some class D AMs have paper-only post-sunset authorizations that do not appear in the current electronic databases. The FCC lost the records of those authorizations (which were granted 40-ish years ago) in one of its database changeovers, but as long as the station itself kept a paper copy, it's still valid.
A simple call or email to an actual person at the station should take care of this.. If the AM station is operating "extra Hours" I am sure whoever pays the power bill will appreciate it. Since the AM is most likely only used to "feed" the FM translator most likely nobody is listening to the AM so anything the operator can do to save money on the AM is a good thing for the operator. I doubt they are selling night programing because of a "post sunset" on the AM, No reason to cheat. Unless you are a DXing the distant 50KW station don't worry. I will make a prediction about this operation without even knowing where it is: Unless the FM translator has a 60 Db signal that goes farther 25 miles from the AM, look for a major downgrade that will allow them to run non directional from a single tower possibly duplexing from another AM tower nearby. There is a good change that the land is more valuable than station.
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