shortspaced stations

[bobdavcav]

What are some shortspaced stations that we seem to have no idea how they got that way? An example I can think of is WKQC to WNOK on 104.7. Since 104.7 was a local channel, when these were allocated in the late 50s, they made sense, but then both were allowed to upgrade when the local channel restrictions were lifted. How were they allowed to upgrade as far as they did though?

 

[Schroedingers Cat]

The short spaced stations were not short spaced when they were authorized. All stations were protected to the 1 mV/m contour (now usually called 60 dBu F(50,50)), even Class Bs. Many operated at low ERP (<10 kW) from AM towers with 150-250 foot HAAT. A cochannel station was allowed if its 40 dBu F(50,10) contour didn't overlap the 60 dB F(50,50) contour of the other stations. First adjacents were allowed if the 54 dBu F(50,10) didn't overlap the 60 dBu F(50,50) of the other. Overlap was permitted over water, foreign soil, etc. Low ERP and HAAT meant much shorter distances were allowed. Then, new rules allowed stations to upgrade in short spaced zones, under Section 73.213. Class Bs were allowed 50 kW, 20 kW, 10 kW, or 5 kW from 500 feet nondirectional in four short spacing zones for cochannel and first adjacent stations. For example, full 50 kW/500 foot facilities were allowed for cochannel Class Bs 125 miles apart, and full Class Class B first adjacent facilities 80 miles apart. FM stations rarely used directional antennas back in those days, but things started getting more aggressive when FM became more and more competitive and overtook AM in the 1970s. Changes in FCC Rules created short spaced stations, not the stations. Stations can now "create" new short spacing under Section 73.215 now, but that is limited to the equivalent of a one class lower station and a minimum of one class lower permitted Section 73.207 distance. It is now an EXTREMELY popular Section. The NAB and the industry went from staunch opposition to being one of the industry's greatest used sections. But often, things would be better still going back to the original contour overlap provisions.

 

[Schroedingers Cat]

One more thing. David's site has all the old station logs showing the ERPs, and later the HAATs of those stations back in the old days. I haven't been able to find a copy online of the Section 73.213 rules in effect during the 1970s. You would be amazed at the low ERPs and HAATs in use before around 1980 and even beyond.

Stations often act as though the other station always created the short spacing. Short spacing is always mutual. Stations that were not short spaced before are allowed to upgrade to full facilities for their Class though, under Section 73.215, if they aren't already authorized full facilities.

 

[ftballfan]

Here are some short-spacings in Michigan and neighboring states I can think of:
94.5B Milwaukee WI to 94.5B Holland, which itself is short-spaced to 94.5C1 Hemlock
96.1B Holland to 96.1C0 Bay City
96.9B Zion IL to 96.9B Grand Rapids
97.9B Chicago IL to 97.9B Grand Rapids
102.1B Milwaukee WI to 102.1B Kalamazoo
102.7B Mt. Clemens to 102.7B Sandusky OH
102.9B Milwaukee WI to 102.9B Grand Rapids
106.9A Brookfield WI to 106.9B Muskegon
The Detroit-Cleveland examples (92.3, 93.1, 95.5, 99.5)

Side note: 100.1 in northeast Wisconsin and western Michigan was CROWDED in the 1980s, between Port Washington, Neenah-Menasha, Sturgeon Bay, Bear Lake, Fremont, and Hastings

 

[Schroedingers Cat]

The Class A channels tended to become more crowded, unless they were precluded by first adjacent Class Bs (within 65 miles) and Class Cs (within 105 miles). Class Cs even precluded second and third adjacent Class As for 65 miles around. 65 miles precludes 13,273 square miles, 105 miles precludes 34,636 square miles. The latter is a greater area than 11 states, and more than half of the area of most states (28), This despite the fact that until the 1980s, Class Cs had an average HAAT of 500-600 feet, except in sparsely populated areas, because of FAA restrictions.

 

[joebtsflk1]

As tightly packed as the band is today, the old class A-B-C system left many small cities with little 3 kW As which didn't provide very good coverage. There was all kinds of room for 25 and 50 kW upgrades of existing class As, and that's what happened in many cases. Some stations had to be prodded into making upgrades, though. I remember the case of a brand new 50 kW C2 that went on the air in 1990. A well-heeled A in one of the primary towns for the C2 didn't like it one bit that they were getting competition. So, they had a co-channel A moved and upgraded to 50 kW. Probably wouldn't have happened without the new station. Granted some areas got over radioed, but overall I think Docket 80-90 and the expanded classes has been good for the listening public. We should have cleared out the sub kilowatt AMs by moving them to FM at that time, but it didn't happen.

 

[Schroedingers Cat]

The problem with the low power (directional) AM stations, is thy were in same areas where you would have had to squeeze in directional FMs instead of creating new fully spaced Class A FMs in the middle of nowhere.

 

[joebtsflk1]

The problem with the low power (directional) AM stations, is thy were in same areas where you would have had to squeeze in directional FMs instead of creating new fully spaced Class A FMs in the middle of nowhere.

Sounds like a scenario from the more crowded northeast...in Iowa there are very few directional class D AMs under 1 kW, and almost without exception all class D AMs managed to get a companion FM by the mid 70s. It could be argued the other way that with most of the class D AMs already equipped with an FM, those class D AMs could simply have been extinguished. But of course owners like to have their cake and eat it too, just like all the rest of us.

In the northeast, most class B FMs were built out to maximum or close to maximum facilities, so they weren't so over-protected. But in Iowa, for every true class C FM in the 70s at 1000 ft or higher, there were a bunch that were under 400 ft. Class Cs above 500 ft were the exception as you point out. Now, most of the old class A FMs from the 70s have been upgraded to C3 or better, and most legacy class Cs are at least C1 and 500 ft or more, with legacy Cs in larger cities like Des Moines, Davenport and Waterloo either at 1000 ft or more, or maxed-out C1s at 981 ft.

 

[Schroedingers Cat]

More Section 73.213 until around 1980.

Cochannel B-B

Stations had to have been short spaced in 1964 as I recall, and to have maintained short spacing since, to be eligible.

Full Spacing Is 150 Miles

125 Miles 50 kW/500 feet HAAT
100 Miles 20 kW/500 feet HAAT
75 Miles 10 kW/500 feet HAAT
<75 Miles 5 kW/500 feet HAAT

First Adjacent B-B

Full Spacing Is 105 Miles

80 Miles 50 kW/500 feet HAAT
65 Miles 20 kW/500 feet HAAT
50 Miles 10 kW/500 feet HAAT
<50 Miles 5 kW/500 feet HAAT

These were the maximum nondirectional facilities authorized. Stations could be directional with the maximum allowable ERP in the short spacing zone along the azimuth connecting the stations. A 2 dB per 10 degrees increase was allowed off the azimuth direction.

Second and Third adjacents were allowed full 50 kW/500 feet facilites.

This was also a very popular Section. After about 1980, negotiated short spacings were allowed, which could be asymmetric. Big city stations often negotiated with smaller market stations for full facilities in their direction, while limiting the smaller market station to as little as 5 kW/500 feet HAAT along the axis in some cases. Bad idea, as it led to very asymmetric results in agreements likely to be made.

Under later 6 kW Class A provisions, big city stations demanded a King's Ransom from small city stations to agree to increase from 3 kW to 6 kW on second and third adjacent channels, when there was mimimal interference. This is becasue the A to B mimimum separation for second and third adjacents INCREASED from 40 to 43 Miles for even 3 kW. Many Class A stations thus remain at 3 kW nondirectional. Many are spaced at close to the minimum 40 miles from previous rules, often rounded from 39.5 miles.

Even though that was the original intent of the 2 dB per 10 degrees rule, it has been codified for all domestic DA patterns, even though higher levels of increase could be used without creating overlap under Section 73.215, and sometimes Section 73.213.

 

[bobdavcav]

Here are some short-spacings in Michigan and neighboring states I can think of:
94.5B Milwaukee WI to 94.5B Holland, which itself is short-spaced to 94.5C1 Hemlock
96.1B Holland to 96.1C0 Bay City
96.9B Zion IL to 96.9B Grand Rapids
97.9B Chicago IL to 97.9B Grand Rapids
102.1B Milwaukee WI to 102.1B Kalamazoo
102.7B Mt. Clemens to 102.7B Sandusky OH
102.9B Milwaukee WI to 102.9B Grand Rapids
106.9A Brookfield WI to 106.9B Muskegon
The Detroit-Cleveland examples (92.3, 93.1, 95.5, 99.5)

Side note: 100.1 in northeast Wisconsin and western Michigan was CROWDED in the 1980s, between Port Washington, Neenah-Menasha, Sturgeon Bay, Bear Lake, Fremont, and Hastings

What about 95.7 B Milwaukee WI to 95.7 B Grand Rapids MI? That looks really tight to me. What I'm not understanding is this, 104.7 in both Charlotte and Columbia would have both been class A stations when they signed on, and have since upgraded, Columbia to C1, Charlotte to C0. How were they allowed to upgrade so much if they run into each other? This spacing stuff is kind of interesting, as I had thought that from 1962 to about 1980, there was one set of rules in affect, and that there would be lots of stations that if they were on the air then, would be shortspaced to existing stations under those rules. I also thought that there was very little resembling today's rules before 1962, which is how we have spacings like WHTZ to WRNB, and WBEB to WCBS to name a few.

 

[Schroedingers Cat]

104.7 was a Class B-C channel. 104.9 was a Class A channel. The stations may have seemed to be Class A because of low ERP/HAAT, but they were actually B or C. By 1984, those stations had to have at least CPs with ERP/HAAT combinations for keeping full Class B or Class C status. Otherwise, they were downgraded to B1 or C1.

In North Carolina, they would be in Zone II so they were Class C.

http://transition.fcc.gov/oet/info/maps/fmzones/fmzones.pdf

WZZM-FM 95.7 Grand Rapids used to have a very low ERP and HAAT. Overlap also could have been excluded over Lake Michigan. So Milwaukee wouldn't have been short spaced until they changed the rules.

Update: In 1966, WZZM-FM was 7.8 kW from 175 feet. WMIL-FM was 25.5 kW from 280 feet. Under old rules, they would have both been protected to the 1 mV/m contour, and overlap, if any, over Lake Michigan could be excluded. Until the FCC changed the rules, they were fully spaced when authorized.

WGRD-FM 97.9 was in the Short Spacing Zone that allowed 20 kW nondirectional. It was short spaced to WSDM/WLUP 97.9 Chicago, WMZK/WJLB 97.9 Detroit, and WSAM-FM/WKCQ 98.1 Saginaw. They moved South of Grand Rapids. Instead of a complicated directional pattern, they opted to stay with reduced ERP (13 kW), equivalent to 20 kW from 500 feet.

 

[Gregg.]

A previous poster mentions 100.3 and 101.1 in both NYC and Philadelphia. Actually, those dial positions are also in Washington DC. But I guess the FCC wasn't watching all that carefully in the early days of FM. 100.3 in Media PA, just outside Philadelphia, went on the air as KYW-FM in the 1940s. Oddly, KYW-AM is also short spaced, only 10 kHz away from 1050 in NYC. They're both 50,000 watts and both are directional away from each other. But it's still unusual to have 50,000 watt stations at 1050 and 1060 only 90 miles apart.

And how about 105.7 in both Baltimore and York PA? York is full power and Baltimore is very close to full power, both Class B. I've read that's the worst short-spacing in the country, less than 50 miles apart. I've also read that York uses a directional antenna.

 

[joebtsflk1]

More Section 73.213 until around 1980.


Cochannel B-B


Stations had to have been short spaced in 1964 as I recall, and to have maintained short spacing since, to be eligible.


Full Spacing Is 150 Miles


125 Miles 50 kW/500 feet HAAT
100 Miles 20 kW/500 feet HAAT
75 Miles 10 kW/500 feet HAAT
<75 Miles 5 kW/500 feet HAAT


First Adjacent B-B


Full Spacing Is 105 Miles


80 Miles 50 kW/500 feet HAAT
65 Miles 20 kW/500 feet HAAT
50 Miles 10 kW/500 feet HAAT
<50 Miles 5 kW/500 feet HAAT


These were the maximum nondirectional facilities authorized. Stations could be directional with the maximum allowable ERP in the short spacing zone along the azimuth connecting the stations. A 2 dB per 10 degrees increase was allowed off the azimuth direction.


Second and Third adjacents were allowed full 50 kW/500 feet facilites.


This was also a very popular Section. After about 1980, negotiated short spacings were allowed, which could be asymmetric. Big city stations often negotiated with smaller market stations for full facilities in their direction, while limiting the smaller market station to as little as 5 kW/500 feet HAAT along the axis in some cases. Bad idea, as it led to very asymmetric results in agreements likely to be made.


Under later 6 kW Class A provisions, big city stations demanded a King's Ransom from small city stations to agree to increase from 3 kW to 6 kW on second and third adjacent channels, when there was mimimal interference. This is becasue the A to B mimimum separation for second and third adjacents INCREASED from 40 to 43 Miles for even 3 kW. Many Class A stations thus remain at 3 kW nondirectional. Many are spaced at close to the minimum 40 miles from previous rules, often rounded from 39.5 miles.


Even though that was the original intent of the 2 dB per 10 degrees rule, it has been codified for all domestic DA patterns, even though higher levels of increase could be used without creating overlap under Section 73.215, and sometimes Section 73.213.

Looking through these separations, at first they look similar to the separations for current-day C2s and C3s. But some of these have to create predicted interference inside the 60 dBu contour

Then with the 2nd/3rd adjacent short-spacings in the grandfather rules, are there full grandfathered Bs that are closer than 30 miles from each other?

 

[Schroedingers Cat]

WLHT 95.7 Grand Rapids and WMAX-FM 96.1 Holland are just 17 miles apart. Another thread cited a similar 24 mile separation. It seems like there are stations on Second Adjacents within the City of License and 70 dBu contour in places like Los Angeles. Seems like I stayed in a hotel near Inglewood and LAX where I couldn't get KOST 103.5 on the hotel room radio between two Class As on 103.1 and 103.9. Seems like it faced North. I think I could see the towers lights in the Hollywood Hills out the window, but KOST was not able to be tuned. Almost all stations are grandfathered there, and otherwise they wouldn't come close to putting a 70 dBu over Los Angeles. Seems like there might be some Second Adjacent Class As authorized not far from there.

 

[K.M. Richards]

Seems like I stayed in a hotel near Inglewood and LAX where I couldn't get KOST 103.5 on the hotel room radio between two Class As on 103.1 and 103.9. Seems like it faced North. I think I could see the towers lights in the Hollywood Hills out the window, but KOST was not able to be tuned. Almost all stations are grandfathered there, and otherwise they wouldn't come close to putting a 70 dBu over Los Angeles. Seems like there might be some Second Adjacent Class As authorized not far from there.

Yes, KDLD/103.1 and KRCD/103.9 have their transmitter sites in Baldwin Hills, to the north of Inglewood and the east of Culver City. KDAY/93.5 and KJLH/102.3 are also in the same immediate area.

 

[Schroedingers Cat]

KOST has a maximum HAAT of nearly 5000 feet above average terrain to the SSW. They have a booster that provides service behind and North of the Mount Wilson range (actually San Gabriel or San Miguel) along Route 14. Cool idea, and one I think you will see more and more in the future, if well planned and designed. With translator frequencies being used up, and no accepted plans for an expanded band, it's the last hope for fill in service.

 

[bobdavcav]

What's interesting about Los Angeles is that when I was there a few years ago, I could get KJLH but not KDAY. Actually I was staying not far from Disneyland. What I was also surprised at was that KROQ, which is weaker than a lot of the other signals in town, was much stronger than some of the other signals, most notably KPWR. Also what seems like a shortspacing allocation is WNEW to WIHT. As for 100.3 101.1, WBIG and sister WMZQ have terrible signals at least where I was in 2009. No I didn't have the best radio at the time, but I could get 101.1 and 107.3 had a great signal, but you had to be in the right spot to get 100.3 or 98.7. What was then WLZL had the best signal by far where I was, at the University of Maryland.

 

[Schroedingers Cat]

Here's the Section 73.213 short spacing provision that was in effect from 1964 to 1987. I didn't realize that it was in effect that long. It is on Page 125 of this link from David's site.

http://www.americanradiohistory.com/Archive-FCC/FCC-Rules-1986.pdf

This is from 1986. It would be better if we could find one where the spacings were in miles, which is how it was originally set up and which is much easier to remember.

 

[K.M. Richards]

What's interesting about Los Angeles is that when I was there a few years ago, I could get KJLH but not KDAY. Actually I was staying not far from Disneyland.

Couple of reasons for that. The main reason is that KJLH has 5600 watts from Baldwin Hills and KDAY has 4200.

KJLH signal approximation*: http://radio-locator.com/cgi-bin/pat?call=KJLH&service=FM&status=L&hours=U
KDAY signal approximation: http://radio-locator.com/cgi-bin/pat?call=KDAY&service=FM&status=L&hours=U

On these maps, the purple border is right about where the signal becomes sufficiently weak to be difficult to receive indoors and marginal on a car radio. With both signals having Anaheim just inside that border, those extra 1400 watts come in handy as they will make the fringe signal a little easier to receive ... apparently just enough in your case to receive KJLH but not KDAY.

What I was also surprised at was that KROQ, which is weaker than a lot of the other signals in town, was much stronger than some of the other signals, most notably KPWR.

KPWR has 25kW from Mount Wilson ... KROQ, 5.5kW from Flint Peak, a much lower elevation. As you might expect, 105.9 has a much more robust signal over Orange County.
KPWR: http://radio-locator.com/cgi-bin/pat?call=KPWR&service=FM&status=L&hours=U
KROQ: http://radio-locator.com/cgi-bin/pat?call=KROQ&service=FM&status=L&hours=U

Hope that helps.

* - Radio-Locator's maps are not a perfect indicator of a station's receivable signal, but they are close enough for comparison purposes. I can look up the actual FCC contour maps and link them if you think it would help answer your question.

 

[Schroedingers Cat]

recnet has the 70, 60, 50, and 40 dBu if you go to the advanced map. But especially in a place like LA, you should try fmfool or some similar type of Longley Rice approximation. Remember those houses in the terrain holes in "Shampoo" and "Play Misty For Me" where you could see the TV antennas at the top of the hill? Those were some of the first MATV systems. Doesn't matter if you are at 5000 feet HAAT, it's still not going to come in at the bottom of a terrain hole, unless it reflects off of something.