USA AM radio "clear channels"

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Re: USA AM radio "clear channels"

Postby dbbubba » Thu Sep 09, 2010 7:49 am

The pattern is interesting.

The red dispersion radiates towards Dallas, but it favors the southern part of the city by a large amount.
That is odd in a way because the prime money spending market is North Dallas.
Southern Dallas is po' folks.
As that lobe radiates out it goes south across Dallas County and skirts below Tarrant County completely missing Ft. Worth.
It largely radiates into an area that is not very populated.
The blue lobes radiate towards Dallas and also towards East Texas and south east of where I live.
The East Texas coverage is funny because that area was fairly rural when that array was built.
I sit in a pretty big null.

The daytime array is almost situated between Dallas and Ft. Worth.
So, they had great daytime coverage and fairly crippled night time coverage.

Note that the antennas are phased in a way that creates the pattern that the signal radiates in.
In the chart you can see what antenna does what.
Pretty cool!
Danny Brown
(I was going call myself Mr. B because I like people to say "MISTER" when they say my name, but then I pitied the fools.)
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Re: USA AM radio "clear channels"

Postby brianroth » Thu Sep 09, 2010 10:16 pm

Dear Danny,

That KLIF history website (which appears to have shut down) had an explanation about the pattern, which had to be designed to protect co- and adjacent-channel stations. I did find this:

http://www.northernstar.no/KLIF3.gif

....which says they are protecting WOWO (Ft. Wayne, IN), KEX (Portland, OR) and XEWK in Guadalajara Mexico, all running 50 kW on 1190. Perhaps the biggest "spoiler" was having to protect WOAI (San Antonio) on adjacent channel 1200.

Best,

Bri

PS, the current call letters of those various stations may have changed, but the same signal patterns would still apply.
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Re: USA AM radio "clear channels"

Postby brianroth » Fri Sep 10, 2010 9:13 pm

Dear Bob,

This topic should be on a Ham Radio forum or something. My aoologies....

Bri

(Who also yacks with Danny about Mundane shit......like AM radio trnasmitters,,,,)
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Re: USA AM radio "clear channels"

Postby THEMIXFIX » Sat Sep 11, 2010 1:10 am

Brian:

Actually, I have no problems when threads go off topic. I actually like it, and it makes it more interesting to me.

But, if it bothers you, , please feel free to move things wherever you want!! :mrgreen:
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Re: USA AM radio "clear channels"

Postby brianroth » Sat Sep 11, 2010 10:46 pm

Bob,

OK, since I guess this IS the "Lounge"!

Best,

Bri
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Re: USA AM radio "clear channels"

Postby dbbubba » Sun Sep 12, 2010 7:47 pm

Hey Brian....
That REALLY hard to read article about KLIF with tiny print pretty much describes exactly what I saw relating to the radiation pattern of the 12 tower array by my house.
They said that the array has a signal that radiates "due west," but in reality it radiates more south by southwest or at about 8:00 o'clock.

The array is in mid Rockwall County and Rockall county is the smallest county in Texas.
We are the county just east of Dallas, but Rockwall County is up along the northeastern side of Dallas county.
The end result is because the KLIF pattern radiates in a south by southwest direction it beams right south of the mid line of Dallas county.
The problem here is that Dallas has historically grown north and the "money" in this market extends north from downtown.
The pattern completely misses the major population of Dallas and in particular, mostly radiates into "hungry heights."
It says that the 12 tower array was built in 1969-70, but even then the growth in Dallas was to the north.

So, in essence, as cool as that array is, it beams into "nowhere!"
Danny Brown
(I was going call myself Mr. B because I like people to say "MISTER" when they say my name, but then I pitied the fools.)
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Re: USA AM radio "clear channels"

Postby brianroth » Sun Sep 12, 2010 8:00 pm

As I vaguely recall, KLIF was originally a daytimer "shoe horned" onto a clear channel frequency. Getting any sort of night time authorization required some pretty heroic engineering. In retrospect, it would have made more sense to move the night antenna array further north so the "laser beam" would travel further north across the Metroplex. But, there may have also been some sort of requirement that they maintained coverage into Oak Cliff, their original city of license.

Man, I sure with that klifhistory.com website was still active, since it went into much greater depth on all the reasons, etc., from a engineering and FCC licensing perspective.

Best,

Bri
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Re: USA AM radio "clear channels"

Postby brianroth » Sun Sep 12, 2010 8:53 pm

Aha! I just remembered the existence of archive.org, and found this:

http://web.archive.org/web/200802172109 ... pgone.html

Unfortunately, none of the pics from the original site made it into the archive, but around 2/3 down that page is further info about the night time pattern and tower array, and earlier in the archive, info about PAMS and TM Productions jingles.

PAMS/TM are yet other famous Dallas operations.

http://www.pams.com/

I loved reading the history, and hearing samples from the various jingle packages. While I see WABC and KLIF samples from the 60's and 70's, the only KOMA jingle they have is from the 50's, a bit before my time <g>.

I also loved the pix of their Ampex TEN track machine....

Best,

Bri
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Re: USA AM radio "clear channels"

Postby NoelM » Sat Jul 23, 2011 1:19 am

640 kHz KFI Los Angeles (although Locator says non-directional, I am puzzled by the info and pattern map)

Brian - I guess that what you were puzzled about with the non-directional pattern, from a single tower antenna system, was the result of different ground conductivities within (and affecting) the coverage area. The better the ground conductivity, the further the MF signal travels. Swampy ground is good. Rocky ground and mountains is poor. Sea water is excellent. NoelM
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Re: USA AM radio "clear channels"

Postby brianroth » Sun Oct 02, 2011 12:35 am

First of all, I'm glad to see this forum is running again. Thanks to whoever renewed the URL!!

I am working on a new studio install (actually, a move/upgrade for a client) in Enid, Oklahoma. FWIW, that city is about 100 miles North and a bit West of Oklahoma City. I'll post some notes about the project in my "Installation" section once it begins really moving along.

On my drive back home on I-35 tonight, I was punching the "seek" button on the car radio, and hitting many of the AM clear channel stations mentioned in the first posts on this thread! It's interesting how well they come in when driving in rural areas at night in the fall/winter.

Best,

Bri
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