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KLAC 570 and KFWB 980

A

alok

I noted that the transmitter sites for KLAC 570 & KFWB 980 are in the same exact spot. I'm guessing that the two stations do not share towers. Were these two stations always together ,at the same site ,if not what year did this happen ?
Were they at one time owned together, if not how & why did these two sites get "so close" ?

Al
 
alok said:
I noted that the transmitter sites for KLAC 570 & KFWB 980 are in the same exact spot. I'm guessing that the two stations do not share towers. Were these two stations always together ,at the same site ,if not what year did this happen ?
Were they at one time owned together, if not how & why did these two sites get "so close" ?

Al
Click to expand...

KFWB shares one of the KLAC towers; KFWB is non-directional day and night so only needs one tower out of the KLAC directional array. They have shared transmitter sites for decades.

The process of tuning two AM stations into shared towers has been used going back over 70 years. It is conceptually simple whereby each station has an antenna tuning unit at its frequency to the tower(s) and a rejection unit so that the other station does not feed back into each transmitter.

In Honolulu, where land is at a premium, there are towers used by as many as four stations.

Other examples in LA: KWKW and KABC share towers, KTNQ and KEIB share towers and KHJ, KBLA and KYPA share towers.

Sharing towers is an economical way for stations to avoid separately having to buy land and get zoning and other permits, and it also helps where good sites are in limited supply due to costs or prior usage of all the "good" land.
 
Last edited:
DavidEduardo said:


KFWB shares one of the KLAC towers; KFWB is non-directional day and night so only needs one tower out of the KLAC directional array. They have shared transmitter sites for decades.

The process of tuning two AM stations into shared towers has been used going back over 70 years. It is conceptually simple whereby each station has an antenna tuning unit at its frequency to the tower(s) and a rejection unit so that the other station does not feed back into each transmitter.

In Honolulu, where land is at a premium, there are towers used by as many as four stations.

Other examples in LA: KWKW and KABC share towers, KTNQ and KEIB share towers and KHJ, KBLA and KYPA share towers.

Sharing towers is an economical way for stations to avoid separately having to buy land and get zoning and other permits, and it also helps where good sites are in limited supply due to costs or prior usage of all the "good" land.
Click to expand...

Doesnt KFOX share a site with KWKW and KABC?
 
My opinion-

In the overall scheme of things it is a nice set up. Main thing is 570 and 980 are not too close in frequency for diplexing, and the tall tower is reasonable for 570. Easy to daydream perfect-world situations, and of course we love to do it :)

However reality of LA real estate is a factor, even 50 years ago. And 50 years ago the present 570/980 location probably seemed far enough out.

And, its my understanding ground conductivity decreases rapidly going eastward. I was told the former KRLA site at Whitter Narrows was about as far east as you should go. KTNQ Industry site is pushing it. In Pomona there is a 250 watt directional.

However, DA patterns needed (especially at night) require being far east to include Orange County and north SF Valley in the pattern. So they are stuck between a rock and a hard place. Or more accurately... between granite, sand and conductivity nirvana. 570 and 980 are fortunate to have what they have. For comparison, look at the Alvarado street site. Oh man...

Take care.
 
Greg Strickland said:
My opinion-

In the overall scheme of things it is a nice set up. Main thing is 570 and 980 are not too close in frequency for diplexing, and the tall tower is reasonable for 570. Easy to daydream perfect-world situations, and of course we love to do it :)

However reality of LA real estate is a factor, even 50 years ago. And 50 years ago the present 570/980 location probably seemed far enough out.

And, its my understanding ground conductivity decreases rapidly going eastward. I was told the former KRLA site at Whitter Narrows was about as far east as you should go. KTNQ Industry site is pushing it. In Pomona there is a 250 watt directional.

However, DA patterns needed (especially at night) require being far east to include Orange County and north SF Valley in the pattern. So they are stuck between a rock and a hard place. Or more accurately... between granite, sand and conductivity nirvana. 570 and 980 are fortunate to have what they have. For comparison, look at the Alvarado street site. Oh man...

Take care.
Click to expand...
KRLA 1110 or KRLA 870?
 
Yes, I should have clarified that... old KRLA on 1110

Take Google Earth or similar website to 34-02-14 -118-03-11
It's south of the 60, Santa Anita Avenue exit.
If I'm not mistaken tower piers are visible.
I believe construction of a new electric power line nearby made it impossible to keep the DA in tolerance, and this was part of the decision to move to Irwindale. Also, I think people were becoming enamored with prospect of an Inland Empire signal.

https://www.oldradio.com/archives/stations/LA/krlapix.htm
 
It's Not Unusual (with apologies to Tom Jones)

As a kid we'd travel through Buffalo on our way to my uncle's in Ohio. At a certain point we'd get WKBW burning up my little 2-transistor radio. I could see the towers through the trees and thought it was cool. When I got the PD job at WGR (550) in Buffalo in 1981 I learned that WKBW (1520) and WGR (550) shared a tower. KB's 50k would blast that high end signal up 'n down the east coast- while 'GR's 5k at the low end would stretch from past Cleveland to Syracuse with little trouble. Where I grew up we couldn't get GR on most radios because of the IF section -and the fact that 1460 was less than 2 miles away. It would show up where WGR should be.

Anyway the GR55 Transmitter is in the same building as KB (once co-owned in the 40s). The building -with the equipment on the 2nd floor must have been a showplace. Walking up the stairs you'd see 2 booths -with transmitter control and processing in each for each station. https://www.fybush.com/sites/2007/site-070727.html When asking Vic Michael (our CE) why GR's high end was never as robust as 'KB's was...his answer was partly because of the filters in the antenna system to block out 'KB's 50k signal from GR - and the fact that radios back then had bandwidth issues at the lower frequencies. It was a hoot that these two technically amazing stations shared the same building and same tower. https://www.fybush.com/sites/2007/site-070727.html KLAC and KFWB's 5 k signals -probably never had quite as much trouble, but they're closer to each other too. (Then there's the 1540 and 930 site).


DavidEduardo said:


KFWB shares one of the KLAC towers; KFWB is non-directional day and night so only needs one tower out of the KLAC directional array. They have shared transmitter sites for decades.

The process of tuning two AM stations into shared towers has been used going back over 70 years. It is conceptually simple whereby each station has an antenna tuning unit at its frequency to the tower(s) and a rejection unit so that the other station does not feed back into each transmitter.

In Honolulu, where land is at a premium, there are towers used by as many as four stations.

Other examples in LA: KWKW and KABC share towers, KTNQ and KEIB share towers and KHJ, KBLA and KYPA share towers.

Sharing towers is an economical way for stations to avoid separately having to buy land and get zoning and other permits, and it also helps where good sites are in limited supply due to costs or prior usage of all the "good" land.
Click to expand...
 
DaveMasonsd said:
KLAC and KFWB's 5 k signals -probably never had quite as much trouble, but they're closer to each other too. (Then there's the 1540 and 930 site).
Click to expand...

1580 and 1230 and 930 share various towers of the KBLA 6 tower array. It's a horrible match for 930, though.

https://www.google.com/maps/@34.085...aGDQPnL0ON30w!2e0!7i16384!8i8192!9m2!1b1!2i32 is a street map closeup of the array.

Generally, the farther away two stations are on the dial, the easier it is to filter each from the other.

Here is what a combiner looks like: (first picture on page is combiner close-up on left, and the engineer, me, standing next to it on the right) https://www.davidgleason.com/1964-1970-Adding-More-Stations.htm
 
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