Higher frequencies like 1520 don't have as much groundwave, of course.
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Closely-Spaced AMs
- Thread starter K8PLW
- Start date
When I was growing up, I liked to hear WMID on 1340 from Atlantic City in the background of the much closer WHAT from Philadelphia during the daytime.
I was also intrigued how WMID had the same news sounder as WABC back in the early 70's.
I was also intrigued how WMID had the same news sounder as WABC back in the early 70's.
400 watts at night and they won't touch each other. I can barely even hear a local AM on 600 watts 30 miles away.
Daytime I'm wondering if terrain is the reason?
As stated they use directional antennas daytime.
That was the ABC Contemporary Network news sounder.
The 1490 void in parts of west central and southern Illinois reflects the loss of the former KFTK East St. Louis, which went silent and was deleted in March 2020. See link below to what led to the station's deletion:
FCC Claims A Convicted Felon Controlled 4 St. Louis Stations.
The owner of four AM stations in the St. Louis area could have its FCC licenses revoked after a multi-year Media Bureau investigation turned up evidence of “serious violations” of
Until 1986, 1520AM had the aforementioned Rossford (Toledo) station as well as a daytimer in Ypsilanti Michigan (just a few miles east of Ann Arbor), In '86 it moved to 990 and got a massively better signal + night service. I believe there was a relaxing of the rules at the time with Canada and Mexico, so Winnipeg being a 1-A didn't matter in Ypsilanti like it used to.
Ann Arbor's 1050AM started low power night service in '86 as well. Prior to that ALL American 1050's (other than New York) I believe had to be daytime only.
I was a freshman at Michigan in the fall of '86
I'm assuming the 1520 Ypsilanti went almost due north to avoid Toledo, tough to find the OLDtimey pattern charts for facilities that don't exist anymore.
It's curious to see so many 1520's that are located in that very tight null of the Buffalo (1-B) station.
When i first stated DX'ing some 40+ years ago early/mid-80's I didn't know so much about how tight the nulls could be, and was stumped at to why from Detroit area, I couldn't get this 50KW buffalo station, after all, Buffalo isn't THAT far away....
Ann Arbor's 1050AM started low power night service in '86 as well. Prior to that ALL American 1050's (other than New York) I believe had to be daytime only.
I was a freshman at Michigan in the fall of '86
I'm assuming the 1520 Ypsilanti went almost due north to avoid Toledo, tough to find the OLDtimey pattern charts for facilities that don't exist anymore.
It's curious to see so many 1520's that are located in that very tight null of the Buffalo (1-B) station.
When i first stated DX'ing some 40+ years ago early/mid-80's I didn't know so much about how tight the nulls could be, and was stumped at to why from Detroit area, I couldn't get this 50KW buffalo station, after all, Buffalo isn't THAT far away....
WBRW (now WWTR) and WOBM (now WJLK) were both daytimers on 1170 kHz and only about 40 miles apart from each other in NJ, until they fought for the chance to move to 1160 kHz and begin full-time operation in the early 1980s, which WOBM won, while WBRW stayed a daytimer on 1170 and went dark in 1990 (but returned under new ownership in 1997).
D
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Not the case any longer, given the surrender of KRZI, but the then 1580 at Waco, TX and 1590 KBUS at Mexia, TX once operated within 40 miles of one another. 1580 shot nearly due south, 1590 non-directional, with one tower at lower power.
Here in Arizona, there is (roughly) a 120-mile separation between Phoenix' KSUN and Tucson's KTuc, both on 1400 kHz. Because the land is (relatively) flat between the two cities, there is an area, roughly from Eloy to the south side of Picacho Peak (the mountain, not the town) where, when you are traveling on I-10, both stations can be heard on car radios (and on good portable receivers too) as fighting for dominance during daytime hours. Since 1400 kHz is a local frequency and most radio stations on it (including these two) broadcast nondirectionally with 1kW 24 hours a day, I do not expect this situation to change any time soon.
CHUM and WHN where something like 300 miles apart, and all through the midwest we heard them together.
from google:
The flight distance between New York City (NYC) and Toronto is approximately 366 miles (589 kilometers)
nice guess
If I have my scant history of FCC rules recalled right, the older standard required stations to put a minimum strength-or-better signal through the downtown of the city of license ..... and that the newer LPFM rules -- or was it translators? -- mandated that the minimum strength-or-better signal cover half the COL's population *or* half its actual square-mileage area.
Now the two FULL-TIME signals on these Radio-Locator maps are not the same frequency, but both were licensed two years before Moses was born. So their 'downtown' area was more specific.
Downtowns that are ten miles apart.
I haven't driven through the joint, so I've never heard the effect(s) in either COL. DXing instinct says that splash in the day from the wee omni should be a factor into the western part of the 1420's COL, and that the bigger 1420 should infringe equally into the east parts of the 1400's turf once the graveyard's skywave chews things up (but that's just a guess).
Oddly, the 1420 used to be a nighttime regular, coming down Long Island Sound to us in Queens. The omni 1400 I heard *once* in the DXing years.
Here is 1420's directional day [attern:
And their nighttime one:
Now the two FULL-TIME signals on these Radio-Locator maps are not the same frequency, but both were licensed two years before Moses was born. So their 'downtown' area was more specific.
Downtowns that are ten miles apart.
I haven't driven through the joint, so I've never heard the effect(s) in either COL. DXing instinct says that splash in the day from the wee omni should be a factor into the western part of the 1420's COL, and that the bigger 1420 should infringe equally into the east parts of the 1400's turf once the graveyard's skywave chews things up (but that's just a guess).
Oddly, the 1420 used to be a nighttime regular, coming down Long Island Sound to us in Queens. The omni 1400 I heard *once* in the DXing years.
Here is 1420's directional day [attern:
And their nighttime one:
Two AM stations 20 kHz apart should not be a problem as long as your receiver has acceptable selectivity and neither of them is transmitting HD Radio (IBOC).
In many nations in Latin America AM stations were spaced as close as 20 kHz apart.
In Mexico City, 690, 710 and 730 are all licensed to that market. In my case, I owned AMs in Quito on both 590 and 570, with transmitters at opposite ends of the market; no problems. And I had neighbors at 550 and 610, too. Farther up the dial in the same city we had 700, 720, 740, 769, 785, 805, 835, 860, 880, 900, 920, 940, 960, 990… and so on up the dial. Nobody had problems, even where one signal might be 10 kw and the near neighbor 250 watts.
Been said that many of those AMs didn't find a place on FM.
Not in Mexico’s several largest markets where FM was highly developed. But nearly everywhere else, about 80% of AMs moved to FM. The other exception was at the U.S. border, where different spacing limits applied due to treaties and agreements with the U.S.
Your comment reminded me that during the 1970s and 1980s, there were many cheap AM/FM receivers on the market that allowed a lot of bleedover, sometimes so much so that nearby outlets 50 kHz away from the AM could not be deciphered or received by those receivers if one were close in proximity to the AM's transmitter.
Case in point. My father's elder sister lived in Napa, CA in a two-story house that was on a hill and very close to the transmitter for the AM outlet on 1440 kHz. When I first visited there in 1976, I had a cheap AM receiver that was unable to pick up the nearby 1490 AM licensed to Petaluma and was barely able to receive the 1510 kHz station licensed to San Rafael, so bad was the bleedover. When we visited there again in late December of 1979, I had my then two-year-old Panasonic RF-2600 with me and had no issues with bleedover whatsoever. (In fact, that radio had more bleedover problems on FM than it ever did on AM or shortwave, but I digress.) At any rate, when the FCC issued regulations on AM and FM frequency spacing (and please correct me if I'm wrong), it used what the possible interference on lower-priced radios might be to determine that spacing.
I did a lot of work in Mexico City in the 70s and always carried cheap AM/FM pocket radios I got duty free when doing layovers in Panama City (Panamá, not FL). On the close spaced stations in the DF I found no problem. But all were in the same city, not remote locations.
The spacing for AM were pretty much determined in the 30’s.