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Stations That Power UP Instead Of Powering Down

M

Matt Cvetic

Just wondered if some of you might shed some light on this for me.....

I've noticed, while studying the AM Logbook for possible DX catches, that there are a handful of AM stations around the country which power UP at night, rather than powering down.

CBEF (540), Windsor, Ontario, for instance, runs 2500 watts in the daytime, but increases to 5000 watts after dark.
WDIZ (590), Panama City, FL, runs 1700 watts daytime, but 2500 watts at night.
WSNR (620), Jersey City, NJ, only runs 3000 watts daytime, but 7600 at night.
And KROX (1260), Crookston, MN, only pushes out 1000 watts in the daylight, but boosts their signal to 5000 watts at nightfall.

And this is only a partial list of those stations who actually power UP after dark, rather than powering down.
They are, by far, in the minority, of course.
However, they seem to be scattered throughout the length and breadth of the country and are not concentrated in any one place.

I'm just curious as to the 'why' of this practice, since 99% of all other stations power down at night (unless, of course, they run the same continuous wattage around the clock).
It's seems a bit odd and I was wondering if some of you could explain the purpose and reason behind it.
Is it due to some geographical oddity?
Does it have to do with some particular 'niche' audience that those stations serve?
Does it require some kind of special dispensation from the FCC to do that?

Just wondering why they do it, and what purpose it serves, and how it makes sense for them to push more wattage at night than in the daytime?
 
In most of these cases, there are other stations on the same (or adjacent) frequencies that are either daytime-only or are using night patterns that don't send much energy in the direction of these stations. When those stations sign off or go to night pattern/power, it opens room for more nighttime signal at each of these stations.

In most cases in the US, these "higher-at-night" facilities are relatively new ones that have taken advantage of a change in FCC rules in the 1980s that replaced a few fixed power levels (1, 2.5, 5, 10, 25, 50 kW) with "dial-a-power," where stations can use whatever power level fits.
 
Ah, I see. Very interesting!

I can't remember which station and frequency right off the top of my head, but I believe there is one which runs 25000 watts daytime, but then jumps up to a full 50,000 watts at night.

Thanks for your reply!
 
They probably want to increase power to cancel out interfering stations via skywave so they can reach the same area at night that they do during the day. Other stations nearby signing off or lowering power at night allows them to increase power at night.
 
Here's a weird example of this....

Nearby WCYN-1400 in Cynthiana, KY runs 500 watts daytime and a kilowatt at night.

You might ask why?

I've heard that WING-1410 in Dayton, Ohio (about 90 miles away) kept the lower daytime power lid on WCYN to avoid interference to their signal in the Cincinnati area. This oddity goes back to the early 1960's when the graveyarders were mostly blanket permitted to up their daytime power to 1,000 watts from the previous max of 250 watts. Later, when graveyarders could use 1,000 watts AT NIGHT, WCYN was permitted to use it as WING's NIGHT signal doesn't come close to covering Cincinnati.
 
Anyone know why KVNS runs with 8.8 kw daytime and .880 kw at night and not the usual 10 kw day/1 kw night like other X band stations?

Not that they need to actually increase power because they sure get their signal out there very well. :)
 
KFMB-760, in San Diego, CA, runs 5,000 watts non-directional daytime, and 50,000 watts directional nighttime, with a cardioid pattern's null directed toward Detroit. Their daytime signal is restricted due to KBRT-740 Avalon, CA, a 10,000-watt daytimer on Santa Catalina Island (they have 113-watt nighttime authority but only use it after 6:00am local time) whose directional signal is mostly thrown toward the mainland. You would think with KBRT being 86 miles away that KFMB wouldn't need to reduce their daytime power, but stations get out over saltwater very well, as many of you already know.
Personally I think with the selectivity of some modern receivers, it seems that KFMB could increase to 50,000 watts daytime without causing interference. (In fact, I've found that it's much easier for most of my radios, even ones with poorer selectivity, to separate two relatively strong stations on immediately adjacent frequencies (±10 kHz) than to try to dig out a weak one 20 kHz divorced from a strong one (one that's upwards of 40-60 dB stronger.))
Also, KBRT has a construction permit to move their transmitter site to the mainland and increase daytime power to 50,000 watts, but their new pattern is supposed to generally send less signal toward San Diego than their current pattern does. I wonder if it's possible KFMB might be able to get a daytime signal upgrade once KBRT begins operating with the new facility?
I suspect David Eduardo may be able to shed more light on the KFMB / KBRT situation.
 
I thought I posted this already, but oh well.

In the 1970s, CFTR 680 Toronto was 10k day & 25k night. A guy at CFTR told me it was due to a 680 in Rochester, which has since moved (could a station in Canada pay to facilitate changes for US stations?). Of course today they are 50k fulltime with that mega-array.

I have one where I live---WZAB "880 the Biz" Sweetwater, 4k day/5k night per Radio-Locator. I still can hardly hear it at night.

There is WGRO 960 Lake City FL---500 w day, 1 kw night.

Isn't the Chicago 950 1k day/5k night?

I wanna say that one of the border-blaster Mexicans, maybe XERF, was low power in the day, and cranked it up at night.

(I think I know now why my last post did not go thru.)

cd
 
Class Cs that use less than 1000 watts daytime (or are directional) usually do so because of adjacent channel Class Bs. Class Cs that use less than 1000 watts at night usually do so because of treaty considerations. Many older stations are still licensed with 1000 watts even though they input less than 1000 watts, but have the minimum Class C efficiency of about 241 mV/m at 1 km. The WING explanation sounds right. If WING doesn't put an NIF contour over an area, it doesn't have to be protected over that area. The wording is something like, if the protected NIF contour is higher than the NIF minimum for that Class (III-A for WING) (used to be 2.5 mV/m, and almost all Class Bs are above that in the CONUS), that becomes the protected contour. I think it's actually supposed to be lower now, but only stations like in Alaska and a handful of others are actually that low.

WGVU 1480 in Kentwood is 2 kW-D, 5 kW-N, DA-N. WSDS 1480 Salem Township is 0.75 kW-D, 3.8 kW-N, DA-2. WEXL 1340 Royal Oak (DA-D) and WTKG 1230 Grand Rapids increase input power at night but are licensed at 1000 watts fulltime. WEXL protects WTRX 1330 in the daytime, and did protect WHMI 1350, which left the AM dial. WTKG protects WBCH 1220.

Expanded band stations use less than 10/1 U1 due to treaty considerations (Come on, WRTH did have a good idea). Speaking of WRTH 590, the radio station that had those call letters, was one of the first to have increased power at night. WRTH 590 Wood River was 0.5/1 U4.

Many stations that increase power at night do so to put an NIF contour over the COL. That is why newer stations with high NIFs often use more power than older stations with lower NIFs.
 
KCOG 1400 in Centerville, Iowa is 500 watts day, 1000 watts night. Probably so they can be heard in town at night.
 
Schroedingers Cat said:
Speaking of WRTH 590, the radio station that had those call letters, was one of the first to have increased power at night. WRTH 590 Wood River was 0.5/1 U4.
Click to expand...

Yes, I remember that one. It signed on in the early 60's as WBBY and ran 500 watts full-time, going to the higher nighttime power arrangement a few years afterward.

One station in Pennsylvania had a head start, by quite a few years. WAEB Allentown ran 500 day/1,000 night from when they first signed on in 1959 until the mid 60's.

cd637299 said:
Isn't the Chicago 950 1k day/5k night?
Click to expand...

Yes it is; call letters are WNTD. I didn't realize that it has been that way for a long time, over 30 years, in fact.
 
Didn't catch it soon enough to edit:

WAEB signed on in 1949.
 
WOUB 1340 in Athens, Ohio is 500 watts daytime and 1000 watts night. The reduced day power is to protect adjacent WYPC 1330 in Wellston (500 watts daytime, 50 watt flea power nighttime authorization).
 
Matt Cvetic said:
Ah, I see. Very interesting!

I can't remember which station and frequency right off the top of my head, but I believe there is one which runs 25000 watts daytime, but then jumps up to a full 50,000 watts at night.

Thanks for your reply!
Click to expand...

I believe WWJ Detroit fits that description
 
Add WSAU, Wausau, WI to the list. 15kw on 550 days...20kw nights. And they still cover more area on their day pattern!
 
I think WHBY 1150 Kimberly is 20000 watts days and 25000 watts nights. WWJ applied for 12 kW day and 50 kW night, but measured the WHAK 960 contours, and they didn't overlap with the new wider lobe WWJ day pattern (5 towers of the 6). They probably also ran radials on their own day signal during the proofs for the 12 kW. Those applications were not complete online. Anyway, they modified the application for 50 kW daytime, and they are 50 kW fulltime now. CHIR/CHYR-7 went from 250 to 500 to 1000 watts night. While it was still on AM before they moved to FM, they were fulltime on 710 with 10000 day and 1000 (700 watts input) watts. They got complaints about it from WLW as I recall, not WOR.
 
Schroedingers Cat said:
I think WHBY 1150 Kimberly is 20000 watts days and 25000 watts nights.
Click to expand...

Correct. 20kw days and 25kw at night aimed northeast. And when I was hanging out on the Northern Ireland online receiver a few months ago, they were a regular.
 
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