Questions about AM Synchronous Transmitters.

[frnkp2000]

Back in the 80's, I worked at WLLH Lowell/Lawrence MA. 1400 AM with 2-1kw transmitters located 9 miles apart. It was my understanding at the time that we were the lone dinosaur in the US, having been "grandfathered" in when the station started in the 1930s, and for that reason, the owners didn't want to give up the second plant, and the uniqueness that we had. Two remote controls, 2 mod monitors, and 2 sets of transmitter readings! Also 2 phone numbers! You could hear the two towers "fighting" when you drove down I-495! We wanted to go AM stereo, but Motorola couldn't make it work. (I still have the unaired "AM Stereo 14" TM jingles on a reel somewhere!) Our Legal ID was "WLLH, Lowell AND Lawrence" (or "Lawrence and Lowell," we'd rotate them.) and we had to effectively serve both COLs as a term of our license. Our newscasts covered that, main operations were in Lowell, but we rented a small office in Methuen (near Lawrence) and set up a mic, mixer, a few cart decks, and a Marti, and had a percentage of our news done live from there.


So anyhoo, my question is, does WLLH still operate in this fashion? And I know there was talk in the 80's of allowing other stations to go synchronous with less power on the other plant to fill null areas. (Much like the FM translators of today) Did this ever happen? Do any of these stations exist today? Thanks in advance for your help!

 

[w9wi]

It's still authorized.

Another synchronous installation that's existed for some time is KKOB-770 Albuquerque, which has a 230-watt synchronous relay in Santa Fe. (I believe it only operates at night, when the main transmitter is directional with a deep null in the direction of Santa Fe)

There are four more recent installations:

KMVL-1220 Madisonville, Texas, with a synchronous relay in Huntsville with 170 watts daytime/11 watts night;
WAPA-680 San Juan, Puerto Rico, with a synchronous relay in Arecibo with 400 watts daytime/570 watts night;
WISO-1260 Ponce, Puerto Rico with two synchronous relays: Mayaguez with 5,000 watts daytime/1,800 watts nighttime, directional antenna;
Aguadilla with 5,000 watts daytime/4,800 watts nighttime, directional antenna.

I would imagine Puerto Rico is particularly suited for synchronous relays, with the major cities separated by mountains which attenuate AM signals.

There have been in the past four more synchronous relays authorized, which have either been cancelled or allowed their licenses/permits to expire:

KRVA-1600 Cockrell Hill, Texas with a synchronous relay in Fort Worth;
KKDA-730 Grande Prairie, Texas with a synchronous relay at Forest Hill with 9 watts nighttime only;
KARA-860 Belen, New Mexico with a synchronous relay at Albuquerque;
KZTU-660 Junction City, Oregon with a synchronous relay at Eugene

WBCB-1490 Levittown, Pennsylvania applied for one in 1996 but the FCC denied the application.

Except for KKOB's, these things all operate under experimental licenses. KKOB exists in a rather unique allocations environment...

 

[jboyd]

There we a couple in Hawaii at one time...JBI

 

[w9wi]

Yeah, I remember that. KIPA-620. Not sure why it doesn't show up in CDBS.

10kw at Kalana and 5kw at Naalehu, per NRC Log.

I only remember this one but wouldn't at all rule out more.

 

[Tom Wells]

I like this idea for my part 15 AM even better than the FM translator idea but the microwave link would be a wallet buster.

 

[davideduardo]

WISO-1260 Ponce, Puerto Rico with two synchronous relays: Mayaguez with 5,000 watts daytime/1,800 watts nighttime, directional antenna;
Aguadilla with 5,000 watts daytime/4,800 watts nighttime, directional antenna.

This one is mystifying. Aguadilla and Mayagüez are essentially adjacent to each other, so 5 kw in one would be a total local in the other.

I would imagine Puerto Rico is particularly suited for synchronous relays, with the major cities separated by mountains which attenuate AM signals.

It's not the mountains, per se. It's the sucky ground conductivity anywhere except along the narrow coastal zone.

 

[frnkp2000]

Thank you all very much for taking time to answer my question! A lot of good information here!

 

[Dale H. Cook]

There have been in the past four more synchronous relays authorized

Another one, in the more distant past, was the earliest one I know of - WBZ, Springfield, MA and WBZA, Boston, MA (the calls were not swapped until Mar-1931), which were using synchronized carriers by September, 1926, according to an article in Radio Broadcast magazine. The synchronization was discussed in the May, 1928 issue of Radio Broadcast in an article entitled "Will New Transmitting Methods Be the Remedy?" By that date WBZ and WBZA synchronized both carrier frequencies and programming

 

[w9wi]

Yep, there's that one -- WBZ/WBZA which lasted until 1962. KFAB (then at Lincoln, Nebraska) and WBBM (Chicago) were theoretically synchronous at night for some time before WWII.

David: Yes, that *is* strange. (I keep forgetting where Aguadilla is..) There are two different callsigns -- WI2XSO Mayaguez & WI3XSO Aguadilla -- and the stations are 17 miles apart.

 

[reelyreal]

I know I've heard rumors that WLLH had once planned a third synchronous transmitter in Haverhill, but I don't really know any details. Anybody know anything?

 

[awsherrill]

There was a synchronous AM operation in eastern Kansas in the 1993-1994 time frame, that involved two separate AM stations with a synchronous transmitter between them. The "main" stations were both on 1340 kHz. One was located in Kansas City, KS, and the other was in Pittsburg, KS. The synchronous booster was located about halfway between the two main signals and ran maybe a couple hundred watts.

As I recall, the format was news/talk with an emphasis on agricultural news, and the Pittsburg station would sometimes break away from the simulcast to air local programming such as HS sports. I listened to the signal once when I was driving south of Kansas City MO on I-49. It was listenable, but there was noticeable variation in the signal strength as the car moved through the interference patterns from the various transmitters.

 

[frnkp2000]

I know I've heard rumors that WLLH had once planned a third synchronous transmitter in Haverhill, but I don't really know any details. Anybody know anything?

There were, in fact, plans for a third transmitter in Haverhill (Thus the "H" in WLLH), but all I was ever told is that "it never happened." I don't know the reason to this day as to why.

Here is a video tour of the studios taken in 1991. (Yes, the walls were carpeted as soundproofing--not claustrophobia-friendly!) Pretty much exactly the same as when I left in '89. This was "state of the art" in its day! Everything was well-maintained, and we could even *smoke* around this stuff! It will show the two remote controllers.

http://www.youtube.com/watch?v=IyLpY2tL1Rk

 

[davideduardo]

Another one, in the more distant past, was the earliest one I know of - WBZ, Springfield, MA and WBZA, Boston, MA (the calls were not swapped until Mar-1931),

Add WBT Charlotte and WBTA Shelby, NC.

Both WBZA and WBTA were shut down to meet the seven station ownership cap when the owners wanted to buy additional stations.

 

[davideduardo]

David: Yes, that *is* strange. (I keep forgetting where Aguadilla is..) There are two different callsigns -- WI2XSO Mayaguez & WI3XSO Aguadilla -- and the stations are 17 miles apart.

I think one of those never got built. I'll see if anyone I know has more information... the problem is that nobody I know in radio in PR cares about AM anymore... and they care even less about what Blanco Pi is doing.

 

[semoochie]

There was supposed to be a synchronous transmitter in Las Vegas, for the main station in Henderson NV. I'm thinking 1280.

 

[davideduardo]

There was supposed to be a synchronous transmitter in Las Vegas, for the main station in Henderson NV. I'm thinking 1280.

870 KLSQ, whenlicensed to Laughlin had a synch to cover Las Vegas. It has since been relicensed to Whitney.

 

[Schroedingers Cat]

It seems like WIMS 1420 Michigan City was going to do this with a 50 watt transmitter in LaPorte, and the 13.9 watt licensed PSSA night facility of WRDT 560 in Royal Oak Township was originally supposed to be synchronous with the 27 watt PSSA in Monroe. From what I've heard, it works well when there's a large amount of interference outside the NIF, like a Class IV/C would have. Auroral conditions would allow the interference fringes to be heard.

 

[Mike Sheridan]

Another one, in the more distant past, was the earliest one I know of - WBZ, Springfield, MA and WBZA, Boston, MA (the calls were not swapped until Mar-1931),

Add WBT Charlotte and WBTA Shelby, NC.

Both WBZA and WBTA were shut down to meet the seven station ownership cap when the owners wanted to buy additional stations.

David, are you sure about those WBTA calls? WBTA started in Batavia, NY around 1949.

I heard the WBT repeater in Shelby went down and nobody noticed so they took it off permanently.

When WJNO West Palm Beach was on 1230 in the 90's they had a repeater in Pompano on 1230 and simulcasted on 1330 in Fort Pierce. I don't know if it really did them any good.

 

[boiseengineer]

KOB put that syncro in after they lost the long fight with WABC to be non-directional at night.
Ironic that they're now co-owned.

 

[frankberry]

KOB didn't want ND at night. They just wanted to keep the existing night pattern. They lost the battle and the FCC forced them to tighten the night pattern so as to provide more protection to WABC.