R
radioguyntx
Guest
This has bothered me for a while, but I was just wondering... What time do AM stations have to kick down the power, and/or switch from daytime to night-time transmitter sites?
-RG
-RG
-
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
All of the one's I've worked for that had to cut back did so at legal sunset time. One station had to change to a directional pattern 15 minutes prior to legal sunset. Many people would like to silence all low power stations at night that are below 500 watts. There are many different viewpoints on this subject.
radioguyntx said:
The required times are attached to the station license.
As I understand it it's average monthly sunrise/sunset, rounded to the nearest 15 minutes.
You can view the times for any particular station by:
- go to http://www.fcc.gov/mb/audio/amq.html
- type the call letters into the "Call Sign:" box
- click "Submit Data"
- click on the station's call letters (they'll probably appear more than once, it doesn't matter which set you click on)
- Scroll down to "Approximate Sunrise & Sunset Times =>"
- click on the name of the time zone
If you do that for the call letters WQSV, you'll find that in January, the station goes to day power at 7am and back to night power at 5pm.
I experienced both sides of the spectrum. In Lexington, Kentucky we'd go to day pattern/power as late as 8am. and power down and change pattern as late as 9pm in the summertime. Meanwhile, 170 miles to the west in Owensboro we'd power up as early as 5am (or close to it....it's been a few years) and power down as early as 4:30 pm in December. Those time zone are crazy thing.
C
CW
Guest
w9wi said:
Sometimes the time required for pattern change/power down is due to the average sunset of the cochannel protected station..say Station A is in Houston protecting Station B in California, they can stay at day power/pattern until sunset in CA...which is 2 hours later than TX (most of it anyway)
G
greenboy
Guest
CW is right that some stations lower there power according to the station they have to protect. For example AM820 WCPT
here in Chicago signs off at 5:30PM CT in December and January where as most other Chicago stations have to sign off
or switch to their nighttime power at 4:15 in December and 4:45 in January, WCPT is protecting WBAP in Fort Worth.
Another example was a small station west of Chicago in De Kalb Il. AM 1560 WSQR(they have recently switched to AM 1180)
they had a daytime power of 198 watts, but at local sunset they had to power down to 23 watts and stayed at that power for
about 2 hours after sunset, then they were required to go down to 17 watts once the sun set in Bakersfield. Ca. So while the
majority of stations have to switch at local sunset some stations are allowed to stay at regular or critical hours power levels
until sunset at the station they are protecting. Another example is AM1530 WCKY in Ohio which stays 50,000 watts with one
tower until sunset in California when they are required to send the 50,000 watts directional to the east with 4 towers.
here in Chicago signs off at 5:30PM CT in December and January where as most other Chicago stations have to sign off
or switch to their nighttime power at 4:15 in December and 4:45 in January, WCPT is protecting WBAP in Fort Worth.
Another example was a small station west of Chicago in De Kalb Il. AM 1560 WSQR(they have recently switched to AM 1180)
they had a daytime power of 198 watts, but at local sunset they had to power down to 23 watts and stayed at that power for
about 2 hours after sunset, then they were required to go down to 17 watts once the sun set in Bakersfield. Ca. So while the
majority of stations have to switch at local sunset some stations are allowed to stay at regular or critical hours power levels
until sunset at the station they are protecting. Another example is AM1530 WCKY in Ohio which stays 50,000 watts with one
tower until sunset in California when they are required to send the 50,000 watts directional to the east with 4 towers.
semoochie said:
Yes indeed, that's how it's done.
And as CW and greenboy described there are other factors that have a bearing on "power up and down times." Many stations around the country have to protect a dominant Class A or B station on the same frequency during critical hours, the two hours immediately after local sunrise and the two hours before local sunset. This could require a station to reduce power, change their pattern, or both. Also note that the dominant station (or stations) requiring protection could include some in other countries, too.
PSRA's or PSSA's (pre-sunrise and post-sunset authority) come into play with many qualifying daytime-only stations, allowing them to operate with lower power from 6 AM to local sunrise and in the evening for varying lengths of time, often up to two hours after sunset. Allowed power levels during PSSA operation can vary widely, with a station generally required to reduce power in steps at certain intervals until sign-off; similarly, PSRA's generally allow stations to increase power in steps from 6 AM until actual sunrise. Some stations simply go with the lowest allowed power in the specified times so they don't have to go though several successive steps; it's often much easier that way! Often a station will elect not to operate for the entire duration of their PSSA since with the power level is so low, and others don't bother with it at all, at least during some months out of the year. Just because a station has an "authorization" doesn't mean they have to use all, or even part of it, and they don't have to tell the FCC about it.
BTW, the station greenboy mentioned, WSQR 1180 Sycamore IL, also has a PSRA and PSSA on their new frequency. As you can see, they're required to afford some serious protection toward the dominant Class A station to the east (WHAM in Rochester) by cutting their power way down: http://svartifoss2.fcc.gov/prod/cdbs/forms/prod/getimportletter_exh.cgi?import_letter_id=4158
http://svartifoss2.fcc.gov/prod/cdbs/forms/prod/getimportletter_exh.cgi?import_letter_id=2124
Note that WSQR is licensed for 900 watts daytime and their official nightime power is one (1) watt, outside of times covered by their PSRA and PSSA.
So a daytimer could have CH, PSRA and PSSA operation, and a full-tiimer could have various power and pattern configurations for daytime, nighttime and critical hours, as well as a PSRA and/or a PSSA, with different hours for each depending on the month. It can all become very confusing for everyone, the on-air staff, the traffic/continuity people, the listeners and, oh yes....the engineers!!!
D
dave388
Guest
id go nuts tryin to remember all that
dave388 said:
At the AM station I do some work at, I had the pleasure of having to completely reprogram their Gentner VRC-2000 (it automatically changes the power levels based on a schedule). It's a Class D station that is licensed for 1 KW daytime and 12 Watts nighttime, however we have a PSRA of 500 Watts from 6 AM until sunrise. Our PSSA is a bit more complicated, but basically at sunset we get to go to 50 Watts and then finally 12 Watts about an hour and a half later.
The FCC provides the radio station with a complete schedule of the required power level changes and we are expected to make those changes as close to the times provided. I dial into our Gentner once a month and synchronize it with WWV so it's as accurate as possible. This has created some unique situations since most other stations don't check their times very frequently... Most recently we received a DX reception report from Finland at 6:02 AM as other stations on the same frequency hadn't yet turned up the power, but we went to 500 Watts.
One thing I didn't include in my earlier post (sheez, I got kinda long-winded there) is, despite the FCC's updated computerized calculations, the PSRA and PSSA power levels for many (but not all) stations fall into two loosely defined categories. Of that group I'd characterize the first subset as unrealistic and the rest as practically useless; understandably there's plenty of overlap between the two. That being said, it's probably a good thing I don't have to deal with the FCC on a daily basis. I suspect I'd be on their list, and it's not the Christmas list.
One of the biggest issues, as I see it, is that the "limiting stations" could just be the "wrong" stations, especially if a directional pattern based on daytime operation is examined. In many cases the smaller station's pattern is already severely restricted in the direction of the limiting station, thereby reducing the potential for "destructive interference" to a minimal level. Secondly, the allowed power levels are often so low that either PSRA or PSSA operation is meaningless. One or two watts just isn't worth the trouble. So despite all the recalculations things really haven't changed that much since the FCC launched the "daytimer relief" program more than twenty years ago. And meanwhile high-powered AM's are being packed into already over-radioed markets on former clear channels at an alarming rate.
(OK, rant mode off...now, off to anger management class. CW, will you be my sponsor?)
One of the biggest issues, as I see it, is that the "limiting stations" could just be the "wrong" stations, especially if a directional pattern based on daytime operation is examined. In many cases the smaller station's pattern is already severely restricted in the direction of the limiting station, thereby reducing the potential for "destructive interference" to a minimal level. Secondly, the allowed power levels are often so low that either PSRA or PSSA operation is meaningless. One or two watts just isn't worth the trouble. So despite all the recalculations things really haven't changed that much since the FCC launched the "daytimer relief" program more than twenty years ago. And meanwhile high-powered AM's are being packed into already over-radioed markets on former clear channels at an alarming rate.
(OK, rant mode off...now, off to anger management class. CW, will you be my sponsor?)
Some more fun with this: You have stations that are directional day and night, with different patterns and/or power, which would be DA-2 operation in FCC lingo. Then, there is the situation of DA-3 operation, with separate patterns/power levels for day, critical hours, and night. Boston has 2 such stations: WBIX 1060, whose DA-3 is designed to protect KYW here in Philly. They run 40 kW-D, 22 kW-CH, and 23.5 kW-N. Boston's other DA-3 is WWZN 1510. They run 50 kW at all times, but I believe they have the DA-3 to protect WLAC Nashville. DanStrassberg, can you help out here???
R
radioguyntx
Guest
Wow, looks like I kinda opened a can of worms! I didn't realize that this stuff was as complicated as it is. I just assumed it was a simple you power up at this time/down at this time.
C
CW
Guest
DG02816 said:
WLAC would be a Class A they have to protect but WLAC has directional at night (strange for a Class A at 50KW to have such a weird pattern)...WWZN is a Class B..looking at their pattern, its looks like they might also be protecting another station...possibly KGA the other Class A (Spokane Washington)??...1510 is a USA Clear freq...so the Class As have priority...and only WLAC and KGA are the only two As...yet KGA is directional WEST at night...and WLAC has nulls toward KGA and WWZN with three lobes in their pattern (how the hell did a Class A get required to protect a Class B?). WWZN runs two towers day and during CH but pulls in the back side of the pattern (DEEP null at 240deg true which is looking at WLAC)....The field ratio changes on tower two (which is at 241 deg from tower one)..thus changing the pattern electrically....then at night, they go 4 towers with a main lobe at about 110 deg true; daytime lobe is 60deg true but very BROAD..(same two towers are used in the night pattern...daytime, the extras are taken out by grounding or floating them and making them "invisible" to the pattern). Night pattern still has a null at 240 deg toward WLAC and MAYBE 100watts ERP in that direction..while having 200,000watts ERP in the main lobe
C
CW
Guest
jd said:
Yeah as soon as I finish the class!!
The FCC is loosing their MIND and causing the rest of us to follow suit...
B
bilco
Guest
The day/night power change are a function of the FCC license which is determined by many factors, mainly location, but protections also come into it. I have three AM stations here in Las Vegas, with transmitters located less than two miles apart. Two at one site, one at the other. The newest station changes pattern in the morning 15 minues earlier than the others but only in January. All other power/pattern changes are identical for all three stations. I suspect that the very slight difference in lat/long might make the difference since it's the one on a site by itself that has the earlier January pattern/power change. That should also make a difference but it doesn't for any other month. Either there is some minute difference in the FCC's computer program, or maybe the newer station is taking advantage of the an FCC typo. If I can find justification for the one early change, I'll apply for a modified license for the other two. 15 minutes earlier return to higher power/better pattern could be worth it, escpecially between 6:45 and 7 AM in January.
Bilco
Bilco
jd said:
which is why we love CHRONTROL!
I believe that is correct.semoochie said:
- Status