contour overlap question

[Elephant]

What are the rules for contour overlap on co-channel, adjacent, second adjacent, and third adjacent AM stations?

I see a possibility for a great AM move and the only other station near it is an adjacent channel in a market 2 hours away. This may require a city of license change, unless the study shows a city grade in the right direction. Would be nice to diplex onto an exisitng tower non-directional.

When does the FCC accept applications for moves?

Thanks. I know you guys have the answers.

 

[ChiefEngineer]

What are the rules for contour overlap on co-channel, adjacent, second adjacent, and third adjacent AM stations?

I see a possibility for a great AM move and the only other station near it is an adjacent channel in a market 2 hours away. This may require a city of license change, unless the study shows a city grade in the right direction. Would be nice to diplex onto an exisitng tower non-directional.

When does the FCC accept applications for moves?

Thanks. I know you guys have the answers.

You need a detailed groundwave and skywave analysis. Jack Mullaney Engineering, Munn Reese. Two good places to start. 5 to 10 thousand dollars. Don't skimp.

City Of License is a Major Change unless there has been a tower site loss (real not made up) and most AM situations are a mess. Does the AM have naother station in the City of License?

If the station already has a 5 mv/2mv in your city from the current site, re-engineering the DA is a possibility. The more power the better chance.

2 hours or 120 miles is a long AM move because of other stations. Just because you can hear it somewhere doen't mean it can move there.

This isn't a yes or no unless you know the station, the city, etc.

Major changes during windows only, (years apart to cause all older facilities to die and go dormant).

Minor changes at any time! That's the news on the Big One.

 

[DanStrassberg]

What are the rules for contour overlap on co-channel, adjacent, second adjacent, and third adjacent AM stations?

I see a possibility for a great AM move and the only other station near it is an adjacent channel in a market 2 hours away. This may require a city of license change, unless the study shows a city grade in the right direction. Would be nice to diplex onto an exisitng tower non-directional.

When does the FCC accept applications for moves?

Thanks. I know you guys have the answers.

Co-channel: no co-channel 0.025 mV/m contours may overlap your 0.5; your 0.025 may not overlap any co-channel's 0.5.
First adjacent: no first-adjacent 0.25 may overlap your 0.5; your 0.25 may not overlap any first adjacent's 0.5
Second adjacent: no overlap of 5 mV/m contours
Third adjacent: no overlap of 25 mV/m contours
At night, the restrictions depend on your NIF and the NIF's of co-channel and first-adjacent-channel stations. You can't add enough signal under any co-channel or first-adjacent to increase its 50%-exclusion NIF. Also, your NIF must cover at least 80% of the CoL (80% of area or 80% of population, whichever is less). If you don't cover 80% of the area of the CoL, you have to prove that you do cover 80% of the population. Not easy to do unless some areas of the CoL are clearly uninhabited and you can prove it.
I don't think CoL changes are major changes any more. I think there was a rule change maybe six months ago that made CoL moves minor changes. BUT the FCC will not allow CoL changes that would strip a community of its only local broadcast service, where local broadcast service means a station licensed to the community--not just a station whose signal covers the community. So unless another station, which is not the only station licensed to its CoL, can be relicensed to your station's CoL, your station can't change its CoL.
There's a lot more to be considered, but that's the short answer to your question.

 

[Sgeirk]

This why I like the engineering board. I oftentimes learn something!

 

[newsperson]

Newsperson responds:

Yes the city of license on an AM station can now be changed without waiting for a major change filing window. There are some complicated procedures inlcuding publishing it in the Federal Register.

Now the only reason an AM station would wait for a filing window is if they were a daytimer and wanted to move to another frequency which is greater thatn 3 up or 3 down. You could do this and maintain your daytimer status. If you are not a daytimer and want another frequency you may as well file for a new station. The only other advantage is that if there are competiting applications the FCC will allow a settlement window (if it's a station change not a new station application). Otherwise there's no deals allowed between applicants.

The change was made becasue of a petition filed by First Broadcasting of Dallas. The move must be within 300 miles and the contours must interfere with each other, in other words only one of the facilties can exist at the same time.

Some of the benefits of the new rule is that (say you are on 900khz) and another station on 900 Khz moves further away to a large city, it may open an opportunity for your 900 Khz. to increase its daytime power.

Does anyone know of any AM stations who are taking advantage of this new rule now?

I will look for your responses.

Newsperson

 

[jd]

Does anyone know of any AM stations who are taking advantage of this new rule now?

One station that comes to mind took advantage of the new rule shortly after it went into effect last year. KBRZ 1460 Freeport TX moved to suburban Houston and increased their daytime power from 500 to 5,000 watts, giving it city-grade coverage of a good portion of the metro area.

Here's a link to pending applications: www.fcc.gov/fcc-bin/amq?list=A