2 stations fighting to get on the frequency

FM does it with frequency!
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TvRadioGuy
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2 stations fighting to get on the frequency

Post by TvRadioGuy » Mon Jan 08, 2018 6:08 pm

I wanted to get your take on this. Know of a situation 3 stations the first station with 9kw are 200 miles apart the second 50 kw is 250 and the 3rd 6kw
is the one that is getting stepped on. The one station 250 miles can be heard most of the time. Sometimes as far 5 miles to the first contour of the class A The second 50kw can on be heard when there is Isotropic ducting. Any Ideas

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Deep Thought
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Re: 2 stations fighting to get on the frequency

Post by Deep Thought » Mon Jan 08, 2018 6:49 pm

Any ideas about what, exactly?

In the USA commercial stations are generally not protected beyond what the spacing table provides, and the "protected service contours" are significantly higher than what even a mediocre radio needs for reception. It is common to "hear" stations far beyond those contours especially in a car.

There isn't anything you can do about tropo ducting...it's a fact of life in the VHF band. However, if the class-A is routinely being squished by distant stations I would suspect the antenna and transmitter, unless the antenna is only ~100 feet above average terrain.
Mark Mueller • Mueller Broadcast Design • La Grange, IL • http://www.muellerbroadcastdesign.com

W2XJ
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Re: 2 stations fighting to get on the frequency

Post by W2XJ » Mon Jan 08, 2018 7:36 pm

Agreed

I had a station in NYC that was short spaced to one in Philly. Every August when the ducting set up Philly would cover over almost all our coverage area. You could see our antenna on Empire and hear Philly. Of course, we were clobbering them. MAD :-) I had a solution - swap frequencies in Philly and simulcast but it didn’t get too far through corporate. ;-(

TvRadioGuy
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Re: 2 stations fighting to get on the frequency

Post by TvRadioGuy » Mon Jan 08, 2018 8:47 pm

I can Understand about ducting. But on a normal day can this happen in Mountainous or Areas with Big Valleys. I can understand a Class C 50 Kw or 100Kw going 100 Miles But not a 9Kw going 200 Miles on a clear day over mountains and valleys. Can you explain.

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Deep Thought
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Re: 2 stations fighting to get on the frequency

Post by Deep Thought » Tue Jan 09, 2018 8:36 am

9 KW at what height? On the FM band antenna height is a huge contributor to how well the station signal propagates. Also, what is the topographic configuration of the "Mountainous or Areas with Big Valleys"? If the class-A is terrain blocked even a relatively weak signal from a distant station with clear line-of-sight to the area will be enough to overpower it.

Where are these stations?
Mark Mueller • Mueller Broadcast Design • La Grange, IL • http://www.muellerbroadcastdesign.com

TvRadioGuy
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Re: 2 stations fighting to get on the frequency

Post by TvRadioGuy » Tue Jan 09, 2018 10:17 am

its not a clear line of sight mountains. Look the elevation I looks like its 2000 feet and the Smaller station is at 1800 feet But there are some valleys in-between. and the distance is about 200 miles.

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