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Tuesday, June 12, 2012

RADIO-TIMETRAVELLER Maps #3

1 Watt At Night - U.S.

1 Watt At Night - U.S.

The ultimate DX. How good (or lucky) a DXer are you? Have you ever tried for extremely low power AM stations at night?

Every night, 15 stations across the U.S. transmit with an output power of only one watt. How far does one watt travel normally, let's say under static conditions during the daytime? I'm glad you asked.

One watt into an omni-directional antenna (1 tower), over medium ground conductivity (8 mS/m), will get you out 10 miles, at which point the signal enters the "fringe" area of reception (0.15 mV/m and less). A good receiver will hear somewhat farther than that. At night, and using a directional pattern, who knows how far that signal will travel? All things are possible.

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CallSign       Freq    Power Class Location                     
-----------------------------------------------------------
WCKB            780        1    D  Dunn, NC                     
WRFM            990        1    D  Muncie, IN                   
WHFB           1060        1    D  Benton Harbor-St. Jo, MI     
KLEY           1130        1    D  Wellington, KS               
WGAB           1180        1    D  Newburgh, IN                 
WSQR           1180        1    D  Sycamore, IL                 
WPGR           1510        1    D  Monroeville, PA              
WENG           1530        1    D  Englewood, FL                
WJJT           1540        1    D  Jellico, TN                  
KBOA           1540        1    D  Kennett, MO                  
WBNL           1540        1    D  Boonville, IN                
KLKC           1540        1    D  Parsons, KS                  
KDYN           1540        1    D  Ozark, AR                    
WZRK           1550        1    D  Lake Geneva, WI              
WSRY           1550        1    D  Elkton, MD

Here's some statistics for our 15 one watt stations, taken from the 5-27-12 FCC database:

All 15 are Class D.

12 are located east of St. Louis, 3 are west of St. Louis.

KLEY-1130, Wellington, Kansas, is the most westerly, leaving no 1 watt stations from there all the way to the west coast.

11 are "W" callsigns. 4 are "K" callsigns.

The 15 stations broadcast using 24 towers.

11 stations broadcast an omni-directional pattern (single tower). 4 broadcast a directional pattern (multi-tower).

1 station is on the FCC "Silent" list: WZRK-1550.

Interesting to note: 5 of the 15 are on the same frequency - 1540 KHz.

The lowest powered daytime station in the FCC's database broadcasts with 135 watts.

The most interesting broadcast pattern is that of WRFM-990, Muncie, Indiana. This station broadcasts using 6 towers. Its pattern projects generally to the north, covering Muncie and Delaware County as shown in the radio-locator graphic. WRFM-990's daytime power is 250 watts.

6 comments:

Greg said...

I'm sure that a 1 watt station could be received by a DXer at night at considerably farther than 10 miles under the right conditions. However, I'm wondering how well it would be received within its actual coverage area. 1 watt isn't much to fight off the skywave interference from all the other stations on the same frequency.

Greg S, radiologbook.blogspot.com

RADIO-TIMETRAVELLER said...

Hi Greg,

That has been my experience with extremely low power stations - the distant skywave interference at night overpowers their weak signal making reception almost impossible.

Case in point. I drive across country most every year, often staying in Hays, Kansas for the night. The next town over is Russell, Kansas (25 miles away) where little KRSL-990 broadcasts at 30 watts at night. It is difficult to receive in Hays due to all the skywave interference, though 30 watts should put in a better than fringe signal strength under groundwave conditions.

In the clear, 1 watt should travel pretty far at night.

Bill

Paul B. Walker, Jr. said...
This comment has been removed by the author.
Paul B. Walker, Jr. said...

WRFM 990 Muncie, IN doesnt operate at night.... line loss and all being accounted for, they can't get power to the back 3 towers.

RADIO-TIMETRAVELLER said...

Hi Paul,

Thanks for your comment and updated information. I see they have a special temporary authority now with the FCC. Will see if I can get my mapping program to show these types of records.

Thanks!

Bill

RADIO-TIMETRAVELLER said...

Paul and All,

Looked into this a little further. Seems the FCC doesn't include antenna engineering records for special temporary authority applications, whether approved or not. That's the reason the map didn't delete the nighttime reference to WRFM-990. They don't even show the approval of the new antenna system yet...they are behind the times I guess.

Bill