FCC Approves MDCL AM Broadcasting

[Bill, KD0HG]

All I can say is, "The Return of Controlled Carrier Modulation".

The FCC has approved the use of what is called "Modulation Dependent Carrier Level" AM broadcasting.

What it amounts to is that smart transmitters can reduce their carrier level during pauses in speech-at less than peak modulation. This is a process designed to reduce the electric bills of high powered stations, it's been suggested that a 50 KW AM station could reduce its annual electric bill by $50,000 by using this technology.

I wonder how this technology will work with the AGC in typical consumer AM receivers.

So, get ready for the return of galloping modulation in the name of energy savings..

The FCC notice and explanation is here.

http://transition.fcc.gov/Daily_Releases/Daily_Business/2011/db0913/DA-11-1535A1.txt

http://www.rbr.com/radio/fcc-paves-way-for-ams-to-save-by-going-green.html

[WD8KDG]

Considering we no longer have to prove how dysfunctional our government is.....................


"No one in their right mind would ever do that"

[W7POW]

Considering we no long have to prove how dysfunctional our government is.....................


"No one in their right mind would ever do that"

So true!

Hey!  Nice driftboat there pal...looks like one I took a ride in once.

[K5UJ]

I thought Hilmer Swanson's design used in the DX50 did something like that.  I guess not--it ran 50 KW unmodulated.

I'd think they'd want carrier to be full power during pauses to quiet down the channel during dead air. 

It will be interesting to see how it works out.  I wonder what impact this would have on IBOC.

[kb3ouk]

that's how i would want it, reduce the carrier level while the carrier is being modulated, which i would think may even increase the readibilty, if the carrier is reduced but the modulating power kept at the same level it would be if there was the full amount of carrier, then INCREASE the carrier to the full level on pauses. I seem to remember reading on here somewhere that a few riceboxes actually seem to run this way, something about the way they were modualting that they were quiter on pauses in modulation than, say a normal transmitter, like something that was plate modulated. think it may also had something to do with the slightly higher percent of negative modulation compared to positive modulation, because a lot of riceboxes want to swing down, not up, on voice peaks.

[WA3VJB]

Great, the pinched-off carrier will let the IBOC trash come in from next door.

[Opcom]

Great, the pinched-off carrier will let the IBOC trash come in from next door.

I guess they expect everyone to buy $$$ a DSP AM BC receiver next. It would be aware of or able to handle the AGC issues. Times are getting ugly. I wish the AM stereo digital crapola would die and go away so I could open up the I.F. bandwidth on my Stromberg-Carlson Hi-Fi AM tuner again.

[Bill, KD0HG]

Great, the pinched-off carrier will let the IBOC trash come in from next door.

I guess they expect everyone to buy $$$ a DSP AM BC receiver next. It would be aware of or able to handle the AGC issues. Times are getting ugly. I wish the AM stereo digital crapola would die and go away so I could open up the I.F. bandwidth on my Stromberg-Carlson Hi-Fi AM tuner again.

Well, I think the overall design of consumer AM receivers needs to get with it.. A diode detector and one IF chip doesn't cut it any more, why haven't they implemented at least synchronous detectors in AM receivers? Oh yes, costs 50 cents more for decent reception.

If I was smart, I'd design and sell AM transmitters using controlled carrier screen modulation like my old Knight T-150 used. Call them GreenRadio Mfg. Co. Watch the S-Meter dance.

Yes, I deal with two Harris DX-50s, both of them are 50 KW carrier, modulated or not. And a 2010 Nautel 50KW NX-50, which might be software upgradeable, once management hears about the potential electric bill savings. Cheese, the thing is already better than 90% efficient.

The IBOC question is a good one, no insight on that yet.

I'm not sold on this technology.

[W7TFO]

Yeah, well, the FCC also approved that Lightsquared junk that ruins GPS within the range of their terrestrial transmissions as well.

Dumb & dumber comes to mind.

73DG

[k4kyv]

Why frig around with crappy controlled carrier, even on the AM foaming-at-the-mouth-wingnut broadcast band, when cheap synchronous detection is feasible using the appropriate DSP/SDR software?

[kb3ouk]

i don't see then why it would make any sense, because most solid state rigs now make 90% or so efficiency, and probably could go even higher, like 99%, depending on the setup. i'd say if someone built a 50 kw class E BC TX it would probably do 99%, the lower you go in frequency, the more efficient a class E TX can get, right? and i think steve, wa1qix, said he built a 160 meter rig that could do something like 95% efficiency, so why can't that be done at MF?

[K5UJ]

They all  need to just tx the full 9 KHz audio NRSC and listeners need to buy pre-1955 octal five tube radios and they'll hear the best AM of their lives.

[flintstone mop]

I has the answer here>>>>>>>>>>>>>>>>>
EVERYONE reduce their transmitter power to 5KW daytime and 1KW nighttime.
The AM band is nothing but chattering and no music, except for the Disney Channel....OR a favorite solution I heard once, is the AM's move to old VHF TV channels and broadcast using FM,,,,,then their would be real effeciency. And no more interference....IBOC lives with better HD.....which is really nice on FM.........The AM band is a headache.........Hey we could inherit that band and have more play room WOW!!!!


hmmmmm Im  gonna write a letter to the FC Commissioners and give them a laugh.
Fred

[KL7OF]

AM foaming at the mouth, wingnut broadcast band???   Very good Don....How do you come up with this stuff???

[ssbothwell SWL]

I has the answer here>>>>>>>>>>>>>>>>>
EVERYONE reduce their transmitter power to 5KW daytime and 1KW nighttime.
The AM band is nothing but chattering and no music, except for the Disney Channel....OR a favorite solution I heard once, is the AM's move to old VHF TV channels and broadcast using FM,,,,,then their would be real effeciency. And no more interference....IBOC lives with better HD.....which is really nice on FM.........The AM band is a headache.........Hey we could inherit that band and have more play room WOW!!!!


hmmmmm Im  gonna write a letter to the FC Commissioners and give them a laugh.
Fred

now that is an uphill battle if i ever heard of one. 

[k4kyv]

AM foaming at the mouth, wingnut broadcast band???   Very good Don....How do you come up with this stuff???

Easily, just by tuning across the band day or night.  Some of the stuff on the air to-day makes Dr. Brinkey's infamous goat-gland rubbish sound mild by comparison.

I would say let the little toy AM radio stations move to the proposed expanded FM band, using TV ch 5&6. This would be particularly helpful for daytimers, or those licensed for micro-power at night. I have noticed that a typical FM station gets out farther in the daytime than even a 50 kw AMer. For example, most of the Nasville FM stations come in here, 50 miles away, much better and with less noise than WSM's 50 kw blowtorch and Blaw-Knox antenna on 650.

I wouldn't want to see the AMBC band go away entirely.  Leave it populated with a few clear-channel stations scattered over the country as in earlier days, and a limited number of regionals, so that the remaining stations on the band could actually be received outside their backyards.  Remember how well the 1 kw from Elisabeth, NJ got out nationwide at night while it was the first and only station to transmit on 1660 (or thereabouts) in the expanded AM band, before the new segment got cluttered up with multiple stations on each channel?

And let them take the IBOC garbage with them, and the remaining stations either transmit 100% analogue or 100% digital, using separate, clearly defined channels that don't overlap.

Of course the FCC probably won't go along with that because it would make too much sense.

Kinda like the CW community that adamantly opposes extending the 40m phone band down to 7100 but rarely uses up to 7125, the TV broadcast industry likewise opposes expanding the FM band, even though only a limited number of TV stations still use channels 5 and 6, or any VHF channel for that matter. Reportedly, the new digital TV signals don't work all that well on VHF.

[KA3EKH]

IBOC, compressed carrier, Cquam Stereo all that junk ant going to help AM it's dead. Maybe if you're in a top 50 market with a 50 kW station you have an audience for you talk or news format but out in the rest of the country forget it. AM broadcast stations are going of the air at a huge rate. Where I work we have a group of five FM stations and two AM and if something expensive happened like loss of  the transmitter site or need of a new pattern we would just turn the license back into the FCC. Maybe if you're in a community with no other media, no FM or television if there is such a place you can make enough to pay the bills but everywhere I have been the only reason most AM stations are on the air is that the same group that owns the two or three FM stations in that market happens to have a AM they inherited when they bought the property. Can think of maybe one or two AM stations that are not part of a group and are operating on their own and don’t know how they do it. The other potential boom for AM is the new ruling allowing AM stations to install FM translators to supplement their coverage area; just what the world needs more FM translators to crowed the FM band. Twenty years ago I had an opportunity to partner into a little 5 kW AM station but the deal went bad, sometimes you never know how lucky you are!

[k4kyv]

I have noticed that a lot of smaller AM stations are merely simulcasting their sister FM outlet (or maybe someone else's). They even give the informal FM station ID (Q106 or similar nonsense) on the AM frequency.

As small town AM stations go dark, that means a lot more 250 to 1000 watt broadcast transmitters floating around for hams to grab and convert.  Either  directly, or as the stations' assets are sold off, others using their old tube type transmitters as standby rigs will be buying up the more efficient solid state units from defunct stations as replacements, making their old hollow-state transmitters newly available, if only some ham can find out about it in time to win the race to the landfill.

Maybe we'll someday have a  "320m band" in the vicinity of 900 kc/s. <200 ft. towers and base insulators are becoming available, too.  A few years ago I bought a spare base insulator for my tower at a hamfest for $25.

But this is not limited to AMBC.  Follow any of the current broadcast industry rags, and you'll see ample gloom-and-doom speculation about the future of terrestrial broadcasting period - using any mode.

[KM1H]

Shouldnt this be on QSO?

[W4RFM]

I agree AM broadcast has it's trouble, but since that is what paid my bills for 40 years I still enjoy it. How many of you listen to AM stations when you are on the road, (town to town or similar) at night.

Yeah, I have my CD of all my 60's favorites that I play also, but sometimes, you just gotta DX on AM and see what you can get.

[Pete, WA2CWA]

I agree AM broadcast has it's trouble, but since that is what paid my bills for 40 years I still enjoy it. How many of you listen to AM stations when you are on the road, (town to town or similar) at night.

Yeah, I have my CD of all my 60's favorites that I play also, but sometimes, you just gotta DX on AM and see what you can get.

Never. Only listen to FM.

[Steve - K4HX]

Lots of people say the same of amateur radio.

Most people will hear what they want to hear in order to support their preconceived notions. Usually they are wrong.

AM foaming at the mouth, wingnut broadcast band???   Very good Don....How do you come up with this stuff???

[k4kyv]

Lots of people say the same of amateur radio.

Ask Burt.

[Opcom]

I has the answer here>>>>>>>>>>>>>>>>>
EVERYONE reduce their transmitter power to 5KW daytime and 1KW nighttime.
The AM band is nothing but chattering and no music, except for the Disney Channel....OR a favorite solution I heard once, is the AM's move to old VHF TV channels and broadcast using FM,,,,,then their would be real effeciency. And no more interference....IBOC lives with better HD.....which is really nice on FM.........The AM band is a headache.........Hey we could inherit that band and have more play room WOW!!!!


hmmmmm Im  gonna write a letter to the FC Commissioners and give them a laugh.
Fred

Hey if the station in Cleburne TX did that, I could not listen to that old-time country music and  'guests' calling in to "trade fair' every day at 0830 while on my way to work on Coppell TX. Its like a honky tonk of the airwaves. I listen to it instead of the programmed local network fed stuff.

[W2PFY]

Around Albany NY the local cable station YNN is simulcasting  on 900 KC at 400 watts daytime and I think 70 watts at night on a tower that is just about 100 feet high. I live part time about 3 miles from the station and it is very strong at night. The tower is a free standing type that used to be the WABY tower. Must have lots of ground radials.