50,000 Watt Stations on North American Clear Channel Frequencies

[stacker]

Shrodingers Cat wrote:

Oddly enough, some of the new former Class III Class B stations with 50 kW and even less have signals in their major lobes which are better than the former Class I-As and I-Bs now lumped together as Class As. Although skywaves are not protected for Class Bs, many have skywaves that many times exceed what the NIF would be at a particular location, and are crystal clear at night and during critical hours on even the least expensive radios.

When the power levels for Class B stations were raised, the FCC missed the boat by not considering the critical hours effect of those higher power stations. As you correctly noted, during critical hours, the higher power stations often enter the protected contours of other B's. I've heard a 50 kw B override another B inside that station's 5 mV contour.

 

[jd]

When the power levels for Class B stations were raised, the FCC missed the boat by not considering the critical hours effect of those higher power stations. As you correctly noted, during critical hours, the higher power stations often enter the protected contours of other B's. I've heard a 50 kw B override another B inside that station's 5 mV contour.

That's very true. Some of these high-powered, highly directional stations can destroy everything in their path during critical hours. One example is KGOW 1560 Bellaire (Houston) TX, a Class B. Technically they're only required to protect the Class A's on the channel, WQEW and KNZR. According to complaints from little KNGR slightly over 250 miles away in Daingerfield TX (a Class D with 1.5kW day) the station got lost amidst the powerful lobe of KGOW, rendering their signal almost useless just a few miles from the tower. This was noted especially during the cooler months, when KGOW is audible almost the entire day in much of northeast Texas.

KNGR has been silent for quite some time, citing transmitter problems, but reportedly they simply couldn't justify staying on the air due to the interference and the station supposedly is for sale. Granted, as a Class D station KNGR didn't have to be considered when KGOW went to 50kW, but even if they had been a Class B they still wouldn't have got any protection from critical hours interference. It would be interesting to know if Class B WPAD Paducah KY receives interference during those hours from KGOW.

 

[cyberdad]

Canada has the same "clear channels" as the US and Mexico...

Mexico used higher than 50-kw going back to before NARBA. Canada long put higher than US levels on regional and local channels... 50 kw on regional channels like 1410 and 980. And they used up to 10 kw, with a directional, on the old Class IV channels in at least one location.

I presume you may be referring to CHUC in Coborg, ON....about 50 miles east of Toronto. They used to be a fairly regular visitor on 1450 in Northern, IL. I've been trying for them without success on the Northern Ireland receiver, which is being discussed in another thread. I think, however, that they've migrated to FM.

 

[jd]

I think, however, that they've migrated to FM.

You're right. This is from the Canadian Communications Foundation website:

2007
After 50 years of service, CHUC-AM (1450 kHz) signed off the air forever at 5:00 p.m., November 7. /snip/ Programming continued on CHUC-FM “107.9 The Breeze”.

 

[cyberdad]

I think, however, that they've migrated to FM.

You're right. This is from the Canadian Communications Foundation website:

2007
After 50 years of service, CHUC-AM (1450 kHz) signed off the air forever at 5:00 p.m., November 7. /snip/ Programming continued on CHUC-FM “107.9 The Breeze”.

Thanks, jd. And BTW....while we can discuss which channels/stations should be considered "clears"....my personal thanks to Gregg for his time and effort with this project...as well as to David for his time and effort in making so much of the research materials available online.

 

[Schroedingers Cat]

Shrodingers Cat wrote:

Oddly enough, some of the new former Class III Class B stations with 50 kW and even less have signals in their major lobes which are better than the former Class I-As and I-Bs now lumped together as Class As. Although skywaves are not protected for Class Bs, many have skywaves that many times exceed what the NIF would be at a particular location, and are crystal clear at night and during critical hours on even the least expensive radios.

When the power levels for Class B stations were raised, the FCC missed the boat by not considering the critical hours effect of those higher power stations. As you correctly noted, during critical hours, the higher power stations often enter the protected contours of other B's. I've heard a 50 kw B override another B inside that station's 5 mV contour.

Two other factors to consider are that Class A 0.1 mV/m groundwave contours are protected from critical hours interference. A Class B, if it were protected from critical hours interference by new regulation, would likely only be protected to the 0.5 mV/m contour at best. Another factor in interference within predicted protected contours, is that the conductivity in many areas is less than M-3, and the reason for the interference is that the desired signal is less than predicted.

I had an email exchange with one of the top consulting engineers in the country about Class B Critical Hours Interference. He didn't deny that trying to introduce such regulation would be unpopular with many AM licensees. He said the best way would be voluntary reduction, which the FCC would probably allow if it conformed to all other regulations. There are incidences where power wars are being waged and considered by licensees affected, but the licensees affected are not likely to benefit, due to grandfathered interference. There are some clever ways to reduce such interference without service loss to either, such as high angle radiation reduction with less horizontal reduction, either directionally or nondirectionally. Use of very tall and/or sectionalized towers is problematic though, with Cost Considerations, FAA, and Local Zoning Regulations.

 

[BRNout]

That's very true. Some of these high-powered, highly directional stations can destroy everything in their path during critical hours. One example is KGOW 1560 Bellaire (Houston) TX, a Class B. Technically they're only required to protect the Class A's on the channel, WQEW and KNZR. According to complaints from little KNGR slightly over 250 miles away in Daingerfield TX (a Class D with 1.5kW day) the station got lost amidst the powerful lobe of KGOW, rendering their signal almost useless just a few miles from the tower. This was noted especially during the cooler months, when KGOW is audible almost the entire day in much of northeast Texas.

jd, KGOW is consistently the strongest US-based AM signal in Costa Rica. I get down there a couple of times a year and KGOW is almost always present. Other US signals come and go (and vary from night to night), but KGOW has a consistently strong signal. Even stronger than KVNS - by quite a large margin.

They've got quite a powerhouse there. Too bad the programming sucks.

 

[richllewis]

I have to add WJNT, Jackson, MS. They are 50,000 watts daytime on 1180 but night time they have to reduce power in order to placate the Cuban Government who uses their 200 KW transmitters to jam R. Marti. If it wasn't for the Cuban's WJNT would also be 50,000 watts at night. For more information go to my post on the Mississippi board how the Cubans have been using their R. Rebelde network to jam R. Marti

 

[w9wi]

No, the Cubans aren't responsible for WJNT's reduced night power.

The Class A station on this channel is WHAM in Rochester, New York -- that's the station that limits WJNT.

(David Eduardo can speak better to this situation but IIRC Cuba is no longer participating in the regional treaty and is not really entitled to *any* protection.)

 

[cyberdad]

No, the Cubans aren't responsible for WJNT's reduced night power.
The Class A station on this channel is WHAM in Rochester, New York -- that's the station that limits WJNT.

Actually, WJNT throws a nighttime lobe to the southeast....in the direction of Cuba. Their null is in the direction of Rochester, NY and WHAM.

 

[davideduardo]

No, the Cubans aren't responsible for WJNT's reduced night power.

The Class A station on this channel is WHAM in Rochester, New York -- that's the station that limits WJNT.

(David Eduardo can speak better to this situation but IIRC Cuba is no longer participating in the regional treaty and is not really entitled to *any* protection.)

Cuba abrogated the NARBA treaty, ironically called the "Havana Treaty" at the time, shortly after Fidel came to power. By the mid-60's they were installing Czech-built Soviet provided transmitters in the 30, 60 and 120 kw sizes all over the island. A 300 kw transmitter, which seldom made power, was used to block Radio Americas and then ended up on Martí's frequency when that went on the air in '84.

Since Cuba no longer notifies the FCC of operations, there is no way any US station can protect them. On the other hand, several US stations such as 610 in Miami and 1040 in the Tampa Bay area were granted higher powers than "normal" due to interference from non-treaty-conforming operations.

 

[davideduardo]

I have to add WJNT, Jackson, MS. They are 50,000 watts daytime on 1180 but night time they have to reduce power in order to placate the Cuban Government who uses their 200 KW transmitters to jam R. Marti. If it wasn't for the Cuban's WJNT would also be 50,000 watts at night. For more information go to my post on the Mississippi board how the Cubans have been using their R. Rebelde network to jam R. Marti

The FCC does not recognize any legal Cuban operation on 1180, so there is nothing for WJNT to protect. However, they must protect operations on 1170 and 1190 as well as several Mexican operations on 1180, too. It's obvious from the pattern that they protect Rochester most severely, with a flattened pattern towards Mexico and the major lobes heading right at Cuba and towards, roughly, the NW.

 

[davideduardo]

The FCC does not recognize any legal Cuban operation on 1180, so there is nothing for WJNT to protect. However, they must protect operations on 1170 and 1190 as well as several Mexican operations on 1180, too. It's obvious from the pattern that they protect Rochester most severely, with a flattened pattern towards Mexico and the major lobes heading right at Cuba and towards, roughly, the NW.

I hit "post" before adding: "Of course, it is in nobody's interest in DC to have any station interfere with the reception of Radio Martí. Any additional power towards Cuba would likely meet objection from USIS; of course no more power can go towards Mexico and even Kalispell requires protection from higher power levels.

 

[cyberdad]

Cuba abrogated the NARBA treaty, ironically called the "Havana Treaty" at the time, shortly after Fidel came to power. By the mid-60's they were installing Czech-built Soviet provided transmitters in the 30, 60 and 120 kw sizes all over the island. A 300 kw transmitter, which seldom made power, was used to block Radio Americas and then ended up on Martí's frequency when that went on the air in '84.

Since Cuba no longer notifies the FCC of operations, there is no way any US station can protect them. On the other hand, several US stations such as 610 in Miami and 1040 in the Tampa Bay area were granted higher powers than "normal" due to interference from non-treaty-conforming operations.

The FCC wasted no time "responding in kind" to Cuba's abrogation of the treaty. As I recall, (then) WAPE and WTIX were granted higher powers (and also nighttime operation for WAPE) as a result of the Cubans parking one of the Czech blowtorches on 690. I still remember ten years later driving around New Orleans and hearing Cuba occasionally breaking through the local WTIX nighttime signal.

Also, I believe during the Bay of Pigs invasion of Cuba in 1961, a few big-signal stations in the south were providing news and other programming segments in Spanish. WWL and KAAY among them.

 

[davideduardo]

Also, I believe during the Bay of Pigs invasion of Cuba in 1961, a few big-signal stations in the south were providing news and other programming segments in Spanish. WWL and KAAY among them.

The most fascinating was Radio Americas on 1160... or was it 1165 then? It was on Swan Island, Honduras, and broadcast news of the great invasion and liberation of Cuba. For years I had a tape of the broadcast, which was sadly emotional.

In around 1967, I was visited in Quito by a salesperson for the Czech transmitters. He was accompanied by a true Man in Black who had to be Politburo in a really nice ( ;D ) Russian suit that made Robert Hall look like Christian Dior. The Czech guy tried to sell me a 30 or a 60 kw, just like the ones in Cuba... and he had photos of the Cuban stations. They offered nice financing, too. He did everything but offer a free Lada with the purchase.

A day later, I got a visit from the Quito Station Chief from The Company who wanted to know everything except the color of the Rusky's socks. The Cold War was rather weird as seen from an underdeveloped country. Between the spooks and the Mossad agents looking for Nazis, there was always something going on...

 

[w9wi]

(Wasn't there a big signal out of Havana on 690 before the Castro revolution? I don't recall reading anything about higher powers for U.S. stations in the immediate aftermath of the revolution, although that may just mean I haven't read the right magazines on David's site yet!)

Also, I believe during the Bay of Pigs invasion of Cuba in 1961, a few big-signal stations in the south were providing news and other programming segments in Spanish. WWL and KAAY among them.

Speaking of the magazines on David's site... if you browse issues from around that time you'll see a fair number of articles about this.

 

[boiseengineer]

All the tries at interference reduction of the AM band over the years has been completely useless and ineffectual. The expanded band has done nothing. The “ratchet” rule is a joke. Ignoring the laws of nature to shove in more AM stations has been the norm for years. Something simple (but politically incorrect) as extending some kind of critical hours protection to all classes would have saved stations like KNGR.

 

[cyberdad]

The most fascinating was Radio Americas on 1160... or was it 1165 then? It was on Swan Island, Honduras, and broadcast news of the great invasion and liberation of Cuba. For years I had a tape of the broadcast, which was sadly emotional.

I recall reading an article about the Swan Island station at the time it was operational. I believe it was in Popular Electronics or some similar type of magazine. Seems to me that it wasn't on 1160 but only slightly off....perhaps 1161. I really don't remember, so perhaps indeed it was 1165.

BTW...The story about the transmitter salesperson and his "politburo" helper was great! Reminds me a little of my own experiences around 1980 selling magazine ads to a Russian laser company.

 

[radionekkid]

Back in the 50's and 60's i remember 1160 and 1140 had real serious heterodynes on them from what i recall 9 kc spaced stations in ths region. Ii cant remember where they were coming from but wiped out 1140 wrva and ksl or wjjd for a time. It seemed to stop in late 60s or early 70s. does anybody remember this going on and where it was coming from?

 

[davideduardo]

Back in the 50's and 60's i remember 1160 and 1140 had real serious heterodynes on them from what i recall 9 kc spaced stations in ths region. Ii cant remember where they were coming from but wiped out 1140 wrva and ksl or wjjd for a time. It seemed to stop in late 60s or early 70s. does anybody remember this going on and where it was coming from?

There were no 9 kHz adhering nations in the Western Hemisphere... You did have a number of Caribbean and Central American nations using 5 kHz channels like 555, 885, 705, 1515, etc. You had 834 in British Honduras, 645 in Suriname, a number of split-channels in the ABC islands, such as Kelkboom 1435 in Curacao. We had St. Pierre et Miquelon on 1375. Costa Rica used 25 kHz intervals, starting at 550, and Ecuador had a slew of xx5 or xxx5 ending channels.

There also were quite a few stations nominally licensed to even 10 kHz intervals but which were known as "drifters" in DX parlance... stations that did not stay where they belonged on the dial. Colombia, through the 70's had, at different times, dozens of these.

The het on 1140 was caused by two (or more... we were never sure) stations in Cuba on the high side of 1140, with the desired result of blocking landfall of WQBA, one of the more anti-Castro stations in Miami. The het on 1160 for some time was Radio Swan / Radio Americas, indirectly controlled by the CIA and run out of an office just off Flagler on 2nd in Miami (Where AIR had its offices, too)... 50 kw directional towards Cuba on 1165 (later moved to 1160, likely due to interference to US stations given its US backing).

Neither the 1140 nor the 1160 hets existed until the 60's... around 1961 for 1165 and in the mid to late 60's for 1140, which did not convert to all Spanish until around '66 or so. There was no reason for either in the 50's, as Castro did not come to power until '59.