Breaking Down AM Clear Channels Further

[ajaynejr]

Recent political events suggest that, depending on the makeup of the upcoming Federal administration, the U.S. may be moving in the direction of a "sharing economy."

Would anyone like to speculate on the consequences of a further breakdown of the AM band clear channels, to "better share" the "sum total" of coverage area within the U.S.?

For example, imagine that the protected skywave contours of class A stations were all limited to a maximum of 250 miles instead of the current 700 miles.

Would many stations be able to benefit by this? Namely class B stations on the clear channels might increase night power meaningfully but all those on the same channel still must protect each other.

This should not be a "ratchet rule." Assume here that no existing station would be required to reduce emissions in one or more directions including for renovating or relocating its own facilities.

 

[Kelly A]

Recent political events suggest that, depending on the makeup of the upcoming Federal administration, the U.S. may be moving in the direction of a "sharing economy."

Answer: When it comes to AM, nobody cares. The Commission threw a set of water wings to AM stations when it came to allowing FM translators. Other than maybe allowing full-digital MA3 operation, don't expect any major allocation or protection changes on the Medium Wave band.

For example, imagine that the protected skywave contours of class A stations were all limited to a maximum of 250 miles instead of the current 700 miles.

Here's how that would work: Assuming the Commission would bother to spend the time and effort to issue an NPRM, the reaction from smaller market and Class C stations who probably over-paid for their 50kW, would scream bloody murder. The idea has been floated before and shot down like a live pigeon wandering onto a shooting range.

This should not be a "ratchet rule." Assume here that no existing station would be required to reduce emissions in one or more directions including for renovating or relocating its own facilities.

The Commission might do away with the "Ratchet Rule", but it would be about 20 years too late. Nobody, and I mean noooo-body is looking to do major upgrades on their AM station. AM is circling the drain. Most owners are just trying to hang on to survive with what's left of their aging audiences.

 

[davideduardo]

For example, imagine that the protected skywave contours of class A stations were all limited to a maximum of 250 miles instead of the current 700 miles.

Would many stations be able to benefit by this? Namely class B stations on the clear channels might increase night power meaningfully but all those on the same channel still must protect each other.

The problem is that the interference via skywave is based on averages and extremes. Moving inward the average protection contour would meant that often enough the interference might reach the edges of the station's own market. And none of the rules for any class take into account the odd propagation conditions around sunset for stations in the East and sunrise farther to the west; any DXer knows how extreme this is.

In any case, the opportunity to improve any existing station would be too expensive today. In fact, stations are reducing power to go to single tower or simpler arrays and not looking to improve.

The latest is 710 in Los Angeles. They are reducing the day power to 33 kw with a less effective pattern and at night well below the existing 10 kw and losing about a third of the LA market in the process. The land in Burbank was worth too much and the station is worth too little.

 

[kevtronics]

The FCC has already been planning to do exactly that since 2015, when they wanted to totally eliminate protection for nighttime skywave signals -- thus ending any remaining concept of a "clear channel":

https://docs.fcc.gov/public/attachments/FCC-15-142A1.pdf

 

[frankberry]

Eliminating skywave protection would be a big mistake. The skywave from a distant 50kW station could ruin even the local coverage from another station on the same frequency.
The FCC needs to rethink this.

 

[Kelly A]

The FCC has already been planning to do exactly that since 2015, when they wanted to totally eliminate protection for nighttime skywave signals -- thus ending any remaining concept of a "clear channel":

https://docs.fcc.gov/public/attachments/FCC-15-142A1.pdf

This will never happen. The only thing the Commission has been considering, are the handful of stations that are interested in doing MA3 modulation, and their protections therein. That includes skywave for MA3.

 

[frankberry]

This will never happen. The only thing the Commission has been considering, are the handful of stations that are interested in doing MA3 modulation, and their protections therein. That includes skywave for MA3.

I can't image that MA3 would do well under skywave conditions due to the inherent phase shifting of the sidebands.

 

[Kelly A]

I can't image that MA3 would do well under skywave conditions due to the inherent phase shifting of the sidebands.

Actually it does pretty well! With far less bandwidth in IBOC digital side band mode, I (used to) listen to HD broadcasts of WCBS, WLW, and WBZ in my car driving around Northern Virginia at night in the Fall and Winter months. Get rid of the AM portion, and you've got even more bits available, but well within the NRSC mask. So far the MA3 tests have shown much clearer sky wave reception than analog because modulation is RMS not peak.

 

[spt87]

Even if they did eliminate the skywave protection - the skywave would still be there are pretty strong in many areas so that any other stations attempting to use the channel at night would likely have trouble. In any case I don't see many AM stations doing anything on the AM side to expand service. Those day timers who got translators are content with that.

I agree on the IBOC observation - the night time skywave even in hybrid mode can be decent from my casual experience.

Even if full digital operation is approved - who will do it? You still have a lot of cars without HD including brand new ones. Not many aftermarket car stereos have it yet almost all of them have iphone/android integration. Some high end home receivers had it but over the last 5 years that has dwindled. Any HD adapters are all disco'ed products available on eBay. It is a repeat of AM Stereo. Everyone is promoting/banking on streaming at this point.

 

[semoochie]

The FCC has already been planning to do exactly that since 2015, when they wanted to totally eliminate protection for nighttime skywave signals -- thus ending any remaining concept of a "clear channel":

https://docs.fcc.gov/public/attachments/FCC-15-142A1.pdf

I believe that the FCC has already responded to this proposal and discontinued full skywave protection. For instance, I'm thinking that first adjacent skywave protection is removed completely as is critical hours. I want to say that co-channel protection is limited to .1mv/m of the groundwave signal only. If this is true, we can probably find it.

 

[kevtronics]

I believe that the FCC has already responded to this proposal and discontinued full skywave protection. For instance, I'm thinking that first adjacent skywave protection is removed completely as is critical hours. I want to say that co-channel protection is limited to .1mv/m of the groundwave signal only. If this is true, we can probably find it.

That's the latest proposal. If it passes, small stations on the "clear channels" would be free to increase their nighttime power (or go from daytime-only to full-time), just as long as the skywave coming from the new, smaller station doesn't interfere with the existing Class A station's groundwave coverage area. That's better than the original proposal, which didn't afford the existing Class A stations any protection against encroachment of the new signals, but it still eliminates protection for the Class A station's skywave coverage area.

 

[Greg Strickland]

Speaking as an older radio person- In Annapolis MD area I enjoy tuning across the AM dial at night and hearing a marvelous assortment of AM stations from other cities. Driving along I reflect that I am probably the only person in the entire County doing this at that moment. For the most part the stations are technically good neighbors, NRSC and economics of modern transmitters has settled in.

A significant and important audience is listening to my employers AM stations in the city, where it is local groundwave coverage.

btw- I hear WFAN 660 and WCBS 880 in the daytime here, and WBZ 1030 frequently comes in astoundingly well even before sunset in Winter (kudos to directional antenna gain, even with me at 234 degrees from them). Hear and astounding well are used in the context of a person who loves radio, of course. Girlfriend says turn that noise off !

 

[Greg Strickland]

Responding to the thread-

FCC has already done many things to help AM. They eliminated ratchet rule, relaxed antenna efficiency rules, eliminated main studio and duplication of programming rules, and permitted moment of methods analysis for directional AM stations to reduce operating cost.

If it is OK to post a link, here is a recent article:

https://www.radioworld.com/news-and-business/business-and-law/am-revitalization-a-big-success-story

My opinion:

FCC is doing a good job of helping AM broadcasters, within framework of everything else on their plate now. Broadcasters are doing the best they can in context of the overall business situation. I see group owners making logical and smart decisions. Each may be in a slightly different situation, but they all are trying to do the right thing.

Despite the consolidation story that dominated, aren't there many stand-alone AM stations in smaller markets owned by individuals or a family? Many are small businesses where every dollar counts. I recall two AM stations that went silent because they lost block programming clients that sustained the business. The station owners were older individuals who inherited the station from a deceased spouse. The individuals simply could not afford to cover operating and compliance cost of the station out of their own personal resources. How mad can anyone get about a situation like this? That's just the way life goes. Fortunately both stations obtained translators and owners were able to sell to a buyer for an amount that seemed to me is appreciated and helpful.