• Get involved.
    We want your input!
    Apply for Membership and join the conversations about everything related to broadcasting.

    After we receive your registration, a moderator will review it. After your registration is approved, you will be permitted to post.
    If you use a disposable or false email address, your registration will be rejected.

    After your membership is approved, please take a minute to tell us a little bit about yourself.
    https://www.radiodiscussions.com/forums/introduce-yourself.1088/

    Thanks in advance and have fun!
    RadioDiscussions Administrators

..... sunrise ..... sunset ..... (w/ any necessary apologies to 'Fiddler' fans)

Steve Green NEPA

Steve Green NEPA

From a long time back I recall a chart or two of sunrise and sunset zones. In the twilight of my recall now, each US time zone got divided into four :15-minute windows.
Sunrise today here in Schuykill County (and Wyoming plus Dauphin counties) was 7:17 AM.
The question here is: what are the rules for AM stations who have to adjust power / pattterns / critical hours gymnastics when the official sunrise occurs at something like 7:07 AM or 6:53 AM?
I realize that many stations now have automated or computerized systems (which would mean a form of adherence) and that the FCC most likely doesn't give a flying one WHAT happens on AM anymore. But when the rules were more strictly enforced, to which :15 minute segment were they rounded off?
 
Steve Green NEPA said:
From a long time back I recall a chart or two of sunrise and sunset zones. In the twilight of my recall now, each US time zone got divided into four :15-minute windows.
Sunrise today here in Schuykill County (and Wyoming plus Dauphin counties) was 7:17 AM.
The question here is: what are the rules for AM stations who have to adjust power / pattterns / critical hours gymnastics when the official sunrise occurs at something like 7:07 AM or 6:53 AM?
I realize that many stations now have automated or computerized systems (which would mean a form of adherence) and that the FCC most likely doesn't give a flying one WHAT happens on AM anymore. But when the rules were more strictly enforced, to which :15 minute segment were they rounded off?
Click to expand...
It's always been the closest quarter-hour to whenever sunrise or sunset is on the 15th of the month.
 
Here's the way the FCC Calculates Sunrise and Sunset Times. It's based on exact geographic coordinates. They are rounded to the nearest 15 minutes, e.g. 8:07 PM is rounded to 8:00 PM, 8:08 rounded to 8:15. Stations in the same city may have different times depending on month. For instance, the WWJ and WXYT transmitters are just a few miles apart, yet during some months, WXYT Sunrise or Sunset may be 15 minutes later than WWJ. WXYT is further West than WWJ.

www.fcc.gov

Local Sunrise Sunset Calculations

Given a set of coordinates (latitude and longitude) in degrees / minutes / seconds, this program will calculate the approximate average monthly sunrise and sunset times at that location. These values are important to those AM stations who must reduce power, cease operations, or change to...
www.fcc.gov www.fcc.gov

In the past, there were tables of Sunrise and Sunset Times to the nearest 15 minutes for many cities in the US. If a station is issued a new license, including small coordinate corrections, the times may be adjusted for the newer calculations.

I use my location to set the Timers on the Malibu Yard Lights. I try to anticipate the times for the next few months to achieve an average time.
 
Last edited:
Status
This thread has been closed due to inactivity. You can create a new thread to discuss this topic.


Back
Top Bottom