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Wmfn 640

cyberdad

cyberdad

Moderator
Staff member
Apparently the CP for the move to the Chicago area from Michigan is for real.

I was driving south on I-57 from Chicago towards Kankakee, when I spotted a four-tower array on my right, right across the road from the WCPQ (99.9) tower. I had no idea who's it was. But the towers were short, so at first I figured it was a local or rimshot signal high on the dial.

Nope...when I checked R-L later, I saw that the array was in the exact location indicated for the WMFN construction permit. I'm not sure if the short towers are either a.) by design, b.) have something to do with the site of a proposed airport nearby, or c.) still under construction.

Anyway, I'll be interested to hear the new signal. 4400 watts day/1800 watts night aimed right at Chicago should produce a fairly respectable result, and figures to be audible 24/7 where I am.

Stay tuned.
 
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The CP shows two towers that are 82 meters and two that are 91.1 meters high. Usually different height towers are designed to give a deeper null at a particular elevation above the horizontal than in the null in the horizontal. That usually is to protect a signal that is fairly close, like WOI or WHLO. WWJ uses different height towers to protect WNTD better without the horizontal null being so deep. But they also may not be complete as I haven't seen them. They are also designed to be top loaded. The really deep null is generally toward WHLO.
 
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Their new maps look pretty impressive,
but they have a sore on their third upper adjacent channel.
 
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Schroedingers Cat said:
The CP shows two towers that are 82 meters and two that are 91.1 meters high. Usually different height towers are designed to give a deeper null at a particular elevation above the horizontal than in the null in the horizontal. That usually is to protect a signal that is fairly close, like WOI or WHLO. WWJ uses different height towers to protect WNTD better without the horizontal null being so deep. But they also may not be complete as I haven't seen them. They are also designed to be top loaded. The really deep null is generally toward WHLO.
Click to expand...

The towers all appeared to be the same height at my casual "driving by them" glance. But of course, that could mean that they're still under construction

@Radioman: Once this gets turned on, it sure won't make KFI any easier, but OTOH, where you and I are (especially me), the signal should be easy enough to null.

@ai4i: Yes....and a pretty big sore at that. They (WSCR) routinely trash WSM around here.
 
They may have built this to some degree to show that progress is being made, to preserve the CP.

Being 30 kHz from WSCR, I doubt if it will interfere much except quite close to the WSCR tower, at least on most receivers. This company and similar ones have built several stations 30 kHz away, fairly close to another local, including KIRN 670 in Simi Valley, CA to KFI 640, WNDZ 750 in Portage, IN to WGN 720 and WBBM 780, and WTOR 770 Jamestown, NY ("Toronto") to CFZM 740.
 
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Schroedingers Cat said:
Being 30 kHz from WSCR, I doubt if it will interfere much except quite close to the WSCR tower...
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I was not referring to actual interference, just legal protectionism.
I do not believe that two, third adjacent channel stations can overlap 25mv/m,
so the new station will have to "protect" the existing one.
 
In Mexico and other countries, stations separated by 30 kHz were routinely allowed in the same community. Maybe David can tell us if it was unrestricted, or what the overlap restrictions were for stations spaced by 30 kHz. Collocation becomes problematic below around 100 kHz, some say 150 kHz, so that wouldn't be an option for interference ratios. Consider that a plan for collocating WNBC, WABC, and WCBS on Columbia Island (as I recall, that was the name of the Island in Long Island Sound near New Rochelle at one time) were rejected for that reason.
 
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Schroedingers Cat said:
In Mexico and other countries, stations separated by 30 kHz were allowed in the same community. Maybe David can tell us if it was unrestricted, or what the overlap restrictions were for stations spaced by 30 kHz. Collocation becomes problematic below around 100 kHz, some say 150 kHz.
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Where I actually owned stations, Ecuador, local stations were separated by 20 kHz. There were no daytimers, and very little limitation on power (although the higher power stations tended to be on the lower part of the dial).

I owned stations on 570 and 590 in Quito. There were other stations on 550, 610, 640, 679, 700, 720, 740, 760, 785, 805, 835 and so on up the dial (actually 805 was mine, also).

I never had any interference issues between my own adjacent channel stations or the ones on either side. I never knew of a radio that could not separate the stations, even if nearer to one transmitter than to another.

Mexico has pretty much cleaned up or cleared out the AM band, but the big city stations could not move to FM. So in Mexico City, we still have 100 kw on 690, 10 kw on 710 and 100 kw on 730 although most of the stations are separated by 30 kHz (540, 560, 590, 620, 660, 690, 710, 730, 760, 790, 830, 860, 900, 940, 970, 1000, 1030, 1060, 1080, 1110, 1150, 1180, 1220 and so on.

In Mexico there were no restrictions on the location of transmitters for any of the allocations back when they were made.

20 kHz separation was common in all of Central America for stations in the same city except Costa Rica where separation was 25 kHz. Again, no restrictions on sites. Colombia used 30 kHz separation on the low part of the dial up to 1000 kHz where the high power stations were located. 20 kHz allowed on the higher frequencies.
 
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My famous copy of the 1969 WRTH showed that at least at the time, the spacing in Mexico City was 30 kHz, as I recall, but I'll have another look. Maybe there were some suburban communities listed. Were the stations 20 kHz separated TLs physically close? Certainly with narrow audio bandwidth, it would be less of a problem. But it would create a bunch of RITOIE problems as well as actual intermod. I used to hear AM RITOIE on stations separated by 140 kHz 1/2 mile apart when the filters became detuned, with just 5000 watts. It was radiated, because you could hear it on a Delco, but only occasionally. Were any extraordinary filtering methods used for 20 kHz and 30 kHz spacings?
 
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When I use the words protectionist and protectionism, I mean it in an economic sense, not a technical one.
Al Capone provided protection to neighborhood business owners which included effective fire and theft coverage.
We no longer listen to receivers with tubes that drift all over the band as they warm up and have wide AFC's on FM.
AM's can be 20 KHz apart and FM's can be 400 or even 300 KHz apart without interference, but with more competition.
 
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Schroedingers Cat said:
My famous copy of the 1969 WRTH showed that at least at the time, the spacing in Mexico City was 30 kHz, as I recall, but I'll have another look. Maybe there were some suburban communities listed. Were the stations 20 kHz separated TLs physically close? Certainly with narrow audio bandwidth, it would be less of a problem. But it would create a bunch of RITOIE problems as well as actual intermod. I used to hear AM RITOIE on stations separated by 140 kHz 1/2 mile apart when the filters became detuned, with just 5000 watts. It was radiated, because you could hear it on a Delco, but only occasionally. Were any extraordinary filtering methods used for 20 kHz and 30 kHz spacings?
Click to expand...

None of the stations I knew of anywhere in Latin America that were 20 kHz apart had anything but a normal ATU or direct final stage to inverted L tuning. The ATUs, where they existed, did not have any bandwidth limiting components, such as very high-Q design. No restrictions on audio bandwidth, other than the normal design of transmitters, was introduced.

When I was an intern in Mexico City in '63, the 690-710-730 stations were on the air, although 690 was lower power (20 kw day and 5 kw night) and 710 was 1 kw. 730 was the same 100 kw beast it is now. Transmitters were in different areas of the city, but all in urban areas. None was a suburban license (in the 60's, only one Mexico City station has a different city of License, XEVIP-1560 in Cd. Satélite, a very close suburban location that was just across the Mexico City / State of Mexico border, much like Bethesda and Washington, DC)

When I built 590 in Quito, it was the first move-in I ever heard of, coming from San Pedro de Amaguaña, about 60 km south of Quito where it was 200 watts on 595 kHz. I brought it into Quito and got it moved to 590. The transmitters for 590 and my existing 570 were at opposite ends of the city, perhaps 40 km apart. Except in areas about 500 meters around each site, I never found a radio that did not clearly separate the two stations.

The most extreme situation I saw was Guatemala City, where stations were all at 20 or 30 kHz separation, and all but a half dozen (out of more than 30) had either very short verticals ( 100 feet or less) or inverted "L" antennas on rooftops in the downtown areas of the city. I did not note any difficulty tuning any of them anywhere.
 
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When I was in Mexico City in the 60s, I was amazed at the short spacing of these stations. I also remember that XEW on 900 used to bleed over on several frequencies. This was quite aggravating for me as I was trying to DX WLS. I had to wait until after midnight when XEW signed off to hear WLS.
 
DavidEduardo said:


Where I actually owned stations, Ecuador, local stations were separated by 20 kHz. There were no daytimers, and very little limitation on power (although the higher power stations tended to be on the lower part of the dial).

I owned stations on 570 and 590 in Quito. There were other stations on 550, 610, 640, 679, 700, 720, 740, 760, 785, 805, 835 and so on up the dial (actually 805 was mine, also).

I never had any interference issues between my own adjacent channel stations or the ones on either side. I never knew of a radio that could not separate the stations, even if nearer to one transmitter than to another.
Click to expand...

What kind of radios did listeners in Quito have? Modern transistor radios? "All-American Fives?" Good-quality general coverage receivers with crystal filters (Hallicrafters/Hammarlund/National) that were good performers on both their AM and SW stations?

Ancient Modulation receivers were much better designed and built prior to the 1990s, especially compared to the single-IC TRF garbage that's been common in consumer electronics for the last 15-20 years.
 
KeithE4 said:
Ancient Modulation receivers were much better designed and built prior to the 1990s,
especially compared to the single-IC TRF garbage that's been common in consumer electronics for the last 15-20 years.
Click to expand...
I have driven with standard Ford Crown Vick Police Interceptor taxi radios from the early, middle, and late 2000's,
and although the audio was muddy, I never had any problems setting the clock by Santa Clara, Cuba's Radio Reloj.
The R. Reloj station is on 570, right next to Miami's WQAM on 560, and I live on Miami Beach.
 
KeithE4 said:
What kind of radios did listeners in Quito have? Modern transistor radios? "All-American Fives?" Good-quality general coverage receivers with crystal filters (Hallicrafters/Hammarlund/National) that were good performers on both their AM and SW stations?
Click to expand...

Portable radios in were mostly Asian imports, particularly the bigger ones with short wave. Until the late 60's the equivalent of boom boxes did not have FM, but did have shortwave. And the brands were things like "Gold Star" and not recognizable ones like Sony or Panasonic the better ones were Grundig, Telefunken. Smaller transistor radios were nearly 100% Asian and non-traditional brands.

Car radios were whatever the car came with. Most less expensive cars were Nissans, Toyotas and the like. More expensive ones were European, like Land Rovers, Peugot, Mercedes, etc. Not much radio listening was in cars, as only the "one percenters" owned cars then.

Home radios were of two kinds. Console radios with record players tended to be German or Philips, while smaller radios were Asian off-brand. Many older radios were still tube based.

In nearly no case were the radios from the USA. Too expensive on the low end and poor quality on the high end.

Because of the late development of TV (late 60's in the big cities only) and the low literacy rate, radio was the dominant advertising medium, often taking 75% or more of ad budgets.
 
radioman148 said:
When I was in Mexico City in the 60s, I was amazed at the short spacing of these stations. I also remember that XEW on 900 used to bleed over on several frequencies. This was quite aggravating for me as I was trying to DX WLS. I had to wait until after midnight when XEW signed off to hear WLS.
Click to expand...

XEW, with its 250 kw, was protected with 40 kHz on either side being clear in the Mexico City area. 890 and 910 were not used in Central Mexico until much later... the 80's I believe. 880 and 920 even were kept clear in the region. The station had political clout due to its enormous audience from the 30's and even into the 60's.

The transmitters they used (three alternating 250 kw units) were built on site and designed for high fidelity.
 
ai4i said:
When I use the words protectionist and protectionism, I mean it in an economic sense, not a technical one.
Al Capone provided protection to neighborhood business owners which included effective fire and theft coverage.
We no longer listen to receivers with tubes that drift all over the band as they warm up and have wide AFC's on FM.
AM's can be 20 KHz apart and FM's can be 400 or even 300 KHz apart without interference, but with more competition.
Click to expand...

Certainly if the deviation on FM was reduced from + or - 75 kHz to + or - 50 kHz or less, you could have more stations. And in the early days of 88-108 FM, the FCC envisioned 400 kHz spaced stations in the same community. You can find those Table of Allotments in the Broadcasting Yearbooks in David's great archives. They use Channel Numbers, so the fact that they are 400 kHz spaced in the same community may not strike you at first until you think about it. But I don't remember the communities listed having more than 20 channels nonetheless. Once again, I'll have to look again. Probably it was the late 1940s, since I was looking for the Histories of post WWII AMs when I found the FM Tables Of Allotments. One of the things that never made sense about the FM Table of Allotments was the fact that cities that were relatively close together each had allotments, resulting in them having many more allotments than isolated single cities which were larger than the combined smaller cities. This might have been fixed had they not changed the rules allowing contour based allotments and 1 mV/m protection or all classes. The dedicated Class A channels also had some allotment effects that could better have been solved with contour protection.
 
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KeithE4 said:
What kind of radios did listeners in Quito have? Modern transistor radios? "All-American Fives?" Good-quality general coverage receivers with crystal filters (Hallicrafters/Hammarlund/National) that were good performers on both their AM and SW stations?

Ancient Modulation receivers were much better designed and built prior to the 1990s, especially compared to the single-IC TRF garbage that's been common in consumer electronics for the last 15-20 years.
Click to expand...

You beat me to it! Everything built in the last 30 years for home radios has been a minor variation of this garbage: http://earmark.net/gesr/Current_Radio_Design.htm
My daughter once had a radio with an AM ceramic filter so wide that a local 660 bled over on, and swamped a local 620. Replacing the ceramic filter made 620 easily receivable. Considering the tuning dial that came with that radio - it was half an inch in diameter to match the volume control - it had 3 numbers "6" "10" and "17" - they obviously expected that nobody would care about the +/- 40 kHz IF bandwidth. Of course with that wide of a bandwidth, AM sounded fantastic! Except if you tuned an HD AM station, unless you were precisely on frequency (not likely with a 1/2 inch dial), the 5-10 kHz HD stuff sounded exactly like static on a distant FM station.

My 20 month old granddaughter can tune a narrow band radio (all Japanese 8 with tuned RF stage and extra IF) with a decent tuning mechanism on channel. Barely talking, she shows a preference for country classics 680 in San Antonio - 180 miles away - and at night WSM 650. Of course that is the only English language music on the AM dial here. Tunes right past the talk, sports, and foreign stuff - with no prompting from me. Just shows how easy it is to use a decently analog tuned radio.

I do remember the 900 from Mexico City, used to get them when I lived in Michigan with minimal problems from WLS. Audio sounded good, but I don't speak the language, so it was just a curiosity. I guess they powered down or something, I think they are there at night in Houston, but pretty chopped up by other stations.
You ask me - that is going the WRONG way to fight interference inside houses.
 
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