AM Radio - Directional Transmitter Antenna Systems - Still Needed?

[awsherrill]

Cell phone/PCS companies want nothing to do with broadcasters, and would fight that idea to the death.

They will happily co-locate on a broadcaster's existing tower, if it suits their needs. And they will try to arrange lease terms that favor their operation over the broadcaster's.

 

[kenglish]

Do cell phone companies even own towers any more? Seems like they just rent from tower-space providers now. I guess it saves them from driving around at dusk, checking tower lights.

 

[Kelly A]

Do cell phone companies even own towers any more? Seems like they just rent from tower-space providers now. I guess it saves them from driving around at dusk, checking tower lights.

Mostly monopoles. T-Mobile for example, owns all their own monopoles. They rent tower space from other companies as required if permitting isn't allowed in that area.

 

[Kelly A]

They will happily co-locate on a broadcaster's existing tower, if it suits their needs. And they will try to arrange lease terms that favor their operation over the broadcaster's.

Back in the good ol' days when broadcasters owned their own towers, they would jump at the opportunity to have a cell phone tenant. Cell PCS companies hold their nose when doing a lease deal with broadcaster's, because the higher power field strength of one or more broadcaster on the tower, mean a lot of extra design and filters for the cell provider.

 

[vchimpanzee]

AT&T has a tower near my house which looks sort of like broadcast towers used to.

 

[trusty]

The first step is to eliminate daytimers. They may have been useful and viable long ago, but not now. If they can be replaced by the equivalent of protected translators, they can serve small to medium markets entirely and also provide useful service to groups of immigrants who tend to concentrate in smaller geographic areas. And, of course, they can be general market stations for a particular part of a big market, too.

Those Robin Mathis 50 kw day and 250 watt night stations and their ilk qualify as "daytimer" as well

Then, look at solutions for highly directional stations that just don't cover much of the market at night or have been grown out of by post-WW II urban sprawl. Those are, in many ways, daytimers too.

Mexico solved the problem and moved over 600 out of about 800 AMs to FM by changing the separation between stations; they realized that the current NARBA standard was based on the technology of the 40's and 50's and tighter assignments can be made. That standard is almost universal in much of the rest of the world. It would, though, require many stations to move to different frequencies to optimally use the band.

The question is whether there are investors willing to back such a plan. We are so far into being a smartphone based society that major changes in FM allocations may be, like AM stereo, too little and too late.

A few years ago, after the AM band expanded from 1600 to 1700kHz, there was talk about expanding the FM band down to 76mHz (Some radios had that capability to also receive FM stations in Japan.). Most of the AMs could move there.

Then, a lot of translators opened up to really crowd out the existing FM band. Many daytime AMs added flea power nighttime AM coverage just to get on FM.

Is the expansion of the FM band still being discussed, or have smartphones made that a moot point?

 

[PTBoardOp94]

Is the expansion of the FM band still being discussed, or have smartphones made that a moot point?

It was never seriously discussed by the Commission. With the latest TV repack, there are more TV channel 5 and 6 stations than there were after the DTV transition. Those two things together suggest the idea is dead.

 

[Kelly A]

It was never seriously discussed by the Commission. With the latest TV repack, there are more TV channel 5 and 6 stations than there were after the DTV transition. Those two things together suggest the idea is dead.

Yep, the idea of the expanded FM band has been around for years, debated, but never really considered. A big reason is that unlike thirty years ago, 99.8% of consumers don't go out and buy new radios. If a radio comes in their new car, great. Because of that lack of interest, a station moving to the expanded band would for the most part, essentially disappear until someone stumbled across them years from now. Not a great business plan.

 

[gr8oldies]

Yep, the idea of the expanded FM band has been around for years, debated, but never really considered. A big reason is that unlike thirty years ago, 99.8% of consumers don't go out and buy new radios. If a radio comes in their new car, great. Because of that lack of interest, a station moving to the expanded band would for the most part, essentially disappear until someone stumbled across them years from now. Not a great business plan.

The expanded FM band down to 76mHz was a fever dream of Radio World and on message boards and Facebook groups like this, but never seriously considered by the FCC. (No one is going to carry a phone and a walkman to hear "Classic Hits 77.7" even if it happened. I remember talk of an "FM2" going back to the 80s in the 220 region, which would have displaced the 220mHz ham band.

 

[Kelly A]

I remember talk of an "FM2" going back to the 80s in the 220 region, which would have displaced the 220mHz ham band.

At that was even in the days when hams actually used the 220 band. Now it's a ghost town. If you call CQ on the 220 band and there's nobody there to hear it, is it wasted spectrum? I say yes!
But it never mattered anyway. Nobody buys new radios anymore.

 

[Mediafrog+]

The expanded FM band down to 76mHz was a fever dream of Radio World and on message boards and Facebook groups like this, but never seriously considered by the FCC.

The time to have planned an expansion of FM down to 76 MHz was 25 to 30 years ago, and making it part of the DTV transition. Way too late now, and other technologies have made it all moot, anyway.

(No one is going to carry a phone and a walkman to hear "Classic Hits 77.7" even if it happened.

And nothing in Japan on exactly 77.7 either, though plenty of stations close by.

I remember talk of an "FM2" going back to the 80s in the 220 region, which would have displaced the 220mHz ham band.

European DAB operates in the vicinity of 220 MHz, perhaps that is what you are thinking of? Idea never went anywhere in the U.S.

 

[Mediafrog+]

At that was even in the days when hams actually used the 220 band. Now it's a ghost town.

220 MHz has always been underutilized. Its propagation characteristics are too similar to 144 MHz, so hams have tended to skip over it and head up to 420 MHz.

 

[gr8oldies]

The time to have planned an expansion of FM down to 76 MHz was 25 to 30 years ago, and making it part of the DTV transition. Way too late now, and other technologies have made it all moot, anyway.

And nothing in Japan on exactly 77.7 either, though plenty of stations close by.

European DAB operates in the vicinity of 220 MHz, perhaps that is what you are thinking of? Idea never went anywhere in the U.S.

No, it was going to be a second analog FM band, and we're talking the early 90s.

 

[Schroedingers Cat]

More like Class A1 or Class A3 STATION UPGRADES for the Class D translators. And allow them to operate with up to 3 kW nondirectional or maximum equivalent 3 kW DA from 100 meters, as long as all other interference ratios to other stations are met. Protect them to the 63 dBu for the new Class as an allowed standard, higher with public interest, need, and convenience considerations, like Canada has done.

Let them simulcast for up to 5 years like the AM Expanded Band, then turn either the AM or the FM off.

Auction off the better abandoned AM facilities, like KZQZ 1430 (WIL), to other AM broadcasters to improve their AM facilities.

I think getting rid of DAs is a bad idea. And all digital transmissions on the AM BCB. Who is going to buy a new radio to receive them? They also need DAs to send digital interference into the ocean or thinly populated areas in Canada to avoid interference to analog. WJR and WABC turned the IBOC off because of huge mutual interference at the present digital powers. Canada has few AMs now anyway, they mostly all moved to FM. The US should have done what Canada has done fitting in new right sized facilities, starting 40 years ago, instead of limiting competition with First Local Service and Rural Radio Initiatives in the middle of nowhere. They could still fit in lower power facilities with DAs in smaller towns, like CKXS 99.1 Wallaceburg, Ontario in Canada.

https://www.fccdata.org/?call=ckxs&ccode=2&city=&state=&country=CA&cansvc=B&party=&party_type=CDN&lang=en

These steps wouldn't even be required if the FCC had reallocated 2-4 MHz of the Low VHF TV Band back when digital TV basically abandoned it. Stations other than Low VHF LPTVs are still migrating to High VHF and UHF when possible.

 

[TomásEstefan]

Perhaps the 100W AM transmitter antenna system could use existing cell phone towers.

KDTD - Wikipedia

en.wikipedia.org

(KC metro) 1340 AM was part of a synchronous AM setup with another 1340 AM to the south, so it should be easy enough to synchronize 10 100W AM local transmitters.


Kirk Bayne

A couple of decades ago or so KKOB 770 was finally forced to change their night pattern or reduce power to prevent interference to WABC (which WABC complained about for years after KOB moved from 1030 to 770). KKOB opted to modify their night pattern to satisfy all concerned, however this would mean that KKOB would no longer put a decent night time signal in Santa Fe, as it falls right in the null. A 1 or 2kw booster station was set up in Santa Fe, phase locked with the main transmitter at Albuquerque. The station sounded fine in Santa Fe as expected. But not driving between cites. You are no longer phase locked in a moving vehicle as you continually drive through the peaks and valleys of the waveform, creating a selective fading effect. This experiment probably would have worked if typical AM car radios used synchronous detection but they don't, just simple diode envelope detectors. As i understand it this experiment was very short lived.
(Back in the mid 1980s Sansui did make an AM car unit with synchronous detection in its AM stereo tuner but we all know how that turned out!)