How does the FCC get coverage maps?

[jras20]

Does the radio station owner itself write it in on paper or does the FCC do the work? The reason why I am asking is because KTXM Hallettsville is showing a greater coverage area than they really are. A LOT greater. The station starts to fade out not even 5 miles going out of Hallettsville. And the FCC got it showing like the station covers the hole county. That would be nice. But thats not the way it is. How can I report that? Its not the right coverage map. KYKM is about right on the money how they cover the area. (Which KYKM and KTXM are both the simalcasting)

 

[Goat Rodeo Cowboy]

The owners who apply to the FCC for licenses hire Consulting Engineers to calculate and prepare the maps. These are submitted to the FCC where they are accepted or rejected. If rejected, pay to have a new one done which appears to be more scientifically accurate.

First issue. What is coverage. Your car radio will probably pick up a station out at the edges further than will your home table radio. Your home table radio will pick up further out than will you little Sony digital Walkman radio that you strap to your arm while doing an afternoon walk. Your hotel clock radio might pick up the station if you are close enough to identify the birds sitting on the transmitter tower. So which radio is accurate. "Listeneable Coverage" is a fleeting, "it depends" issue.

Second issue. AM and FM present differing challenges on estimating where a station can be heard. For FM the terrain, the hilliness can cause shadowing and multipath. The FM maps are called 50/50 maps or something like that. It's like when the weather forcast says you have a 30% probability of rain in this location? Will you have rain? Maybe. Will you hear the station at the edge of the circle on the map? 50% probability. And that may vary from day to day based on atmospheric conditions. I live about 50 miles from most of the Atlanta FM towers. I am out in the country! When I leave home and punch up the NPR station it is always a crap shoot whether I will get signal today. The MAP does not change daily depending on weather.

Third issue. I don't know if you are aware of this, but some people do not file accurate income tax returns. They hide income. Sometimes engineers drank too much last night or something and they calculate a map that is not totally accurate and the FCC engineers and clerks who receive them, time stamp them don't catch the error.

Fourth issue. Read the tax return example again. Sometimes owners do not BUILD the station exactly the way the engineer designed the station. Antenna lower on the tower than licensed. Substituted a transmitter following a lightning strike and not sending exactly the amount of electricity to the antenna as the license calls for.

Fifth issue. Read the tax return example again. Sometimes the owner of another station 90, 120 or 150 miles away is the bad guy who lied to the FCC, changed his antenna, put extra hamsters in the treadmill of his transmitters and he is sending interference signal your way blocking the signal you are trying to hear.

sixth issue. Natural and man-made static and interference levels have increased in the air around us. Maybe the algorithms the Consulting Engineers use (approved by the FCC) need to be changed to recognize what exists in the air around us TODAY, not what was present 10, 20 or 30 years ago.

Seventh issue. We talked in Issue four about how the station installed it's transmitting antenna. What about your receiving antenna. In a perfect world every time to retune your car radio you would stop and adjust the length of your receiving antenna. You antenna may be of a length that picks up one station very well but does not pick up KTXM well at all. My little Sony Walkman depends on the wire to the earphones for part of it's antenna. As I move, lean over, walk through the curve in the road, the antenna is constantly changing in shape and length. Out here 50 miles out the station comes and goes to the point I have to forget about Terri Gross and settle for the preacher on the hilltop locally or the head-banging rowdy music on the rim-shot transmittler 10 miles away.

There are more issues why maps of radio coverage may not match the FCC published maps, but this is getting boring by now, and we haven't even touched A.M. yet.

 

[w9wi]

Does the radio station owner itself write it in on paper or does the FCC do the work? The reason why I am asking is because KTXM Hallettsville is showing a greater coverage area than they really are. A LOT greater. The station starts to fade out not even 5 miles going out of Hallettsville. And the FCC got it showing like the station covers the hole county. That would be nice. But thats not the way it is. How can I report that? Its not the right coverage map. KYKM is about right on the money how they cover the area. (Which KYKM and KTXM are both the simalcasting)

Depends on what coverage maps you're looking at... Stations are expected to file maps with their applications, to prove they put a principal-community signal over the principal community and that they don't interfere with anyone else. Those are prepared by an engineering firm hired by the station.

The FCC website has links to coverage maps the Commission has calculated themselves, using the technical figures on the station's application.

Coverage maps are only an estimate. Whether you actually get the station within that circle depends GREATLY upon your receiver.

The FCC regards 60dBu as enough signal to provide useful coverage. On a cheap "personal stereo" 70dBu may not be enough. On a typical car radio 50dBu is plenty. If you have a decent tuner and a rooftop antenna, 30dBu may be enough.

Maps that show a continuous line (instead of a bunch of dots) generally don't take terrain into effect. Of course, terrain *does*, in practice, affect FM signal strength! Right now for the most part I'm only seeing terrain considered for TV, not FM.

 

[jd]

Of course, terrain *does*, in practice, affect FM signal strength!

In the case of KTXM terrain really isn't really a problem since most of Lavaca County is fairly flat. Sounds like a transmitter or antenna issue.

The station starts to fade out not even 5 miles going out of Hallettsville. And the FCC got it showing like the station covers the hole county. That would be nice. But thats not the way it is. How can I report that?

Last time I was through there I didn't notice the signal being that bad. You might want to try calling (361) 798-4333 or seeing if you can speak to a real person at the studio, which so far as I know, is still on North Main at West 4th Street (US 77/90A).

 

[jras20]

Thanks for all the info. From what Radio-locator has (from the FCC info also.) My place is in the 64dbu area. None of my radios pick it up. I am about 12 miles southeast of the antenna. I wonder if they just have it pointed more North.? It would make sense if they did for them to report that to the FCC.

 

[jras20]

KTXM really must have problems, I was not even a mile in Hallitsville and KTXM was fading out. They are broadcasting more like a translator than a regular commercial station.

 

[Footsteps of Fessenden]

Uh.. the station has had some equipment problems and have filed THAT with the FCC.

Obama has not given every engineer enough money to buy a full set of standby equipment for a station. Yet.

http://fjallfoss.fcc.gov/cgi-bin/ws...xt=25&appn=101297858&formid=911&fac_num=77834

Exhibit 4
Description: EXTRAORDINARY CIRCUMSTANCES

ON JANUARY 15, 2009, STATION KTXM BEGAN OPERATING WITH REDUCED POWER DUE TO A DEFECT IN THE STATION'S ANTENNA. SPECIAL TEMPORARY AUTHORITY IS REQUESTED IN ORDER TO ALLOW SUFFICIENT TIME TO REPAIR KTXM'S ANTENNA. THE LICENSEE EXPECTS THAT THE STATION WILL RESUME FULL OPERATION BY MARCH 31, 2009. THE LICENSEE ALSO REQUESTS THAT THE COMMISSION WAIVE THE NOTIFICATION REQUIREMENTS SET FORTH IN SECTION 73.1560 (D) OF THE RULES CONCERNING OPERATION WITH REDUCED POWER; THE FAILURE TO COMPLY WAS DUE TO MISCOMMUNICATION WITH THE STATION'S ENGINEER.

 

[Footsteps of Fessenden]

One more thing. The FCC gave them until 6/2 to get it fixed just in case the did not make it by today.

http://fjallfoss.fcc.gov/cgi-bin/ws.exe/prod/cdbs/pubacc/prod/app_det.pl?Application_id=1297858

Application Search Details
File Number: BSTA-20090227ABB
Call Sign: KTXM
Facility Id: 77834
FRN: 0017768342
Applicant Name: KREMLING ENTERPRISES, INC.
Frequency:
Channel:
Community of License: HALLETTSVILLE, TX
Application Type: SPECIAL TEMPORARY AUTHORITY
Status: GRANTED
Status Date: 03/02/2009
Expiration Date: 06/02/2009
Tolling Code:
Application Service: FM
Disposed Date: 03/02/2009
Accepted Date: 03/02/2009
Last Public Notice:
Last Report Number:

 

[jras20]

Thanks for the info, that explains it. I tried to email the station from the old web site but the email kicked back to me. I'll be able to check it over the weekend to see if they are full power now.

 

[Footsteps of Fessenden]

It is cool they took the time to get the STA from the FCC. So often stations get wound up in the moment of trying to fix things and it never gets done.

Hats, and pocket protectors, off to them for doing it right.