Kintronic Talks AM With FCC

[tomservo]

If I get the chance, I'll see if I can do an A/B recording of my local AM station. They run a translator and play music most mornings, so if I can catch them doing tunes it should make for a good comparison between AM & the FM translator. Both are mono, both have basic processing. I have an AMAX AM stereo Sony Walkman for AM and I can use my Radio Shack portable for FM.

I'm so close to the tower that even on night power I get no whistle, whine or any other AM artifact so recordings always come out good.

 

[semoochie]

"You lose both AM and FM in tunnels..." I don't know how you can say that. FM is supposed to penetrate tunnels and I don't have any problem, as long as the signal is strong. I once had a problem in the Cascade Range about 100 miles from the station but that hardly counts.

 

[rbrucecarter5]

"You lose both AM and FM in tunnels..." I don't know how you can say that. FM is supposed to penetrate tunnels and I don't have any problem, as long as the signal is strong. I once had a problem in the Cascade Range about 100 miles from the station but that hardly counts.

I-10 goes under the bay in Mobile. It doesn't matter AM or FM. Both are entirely gone at the bottom of the tunnel. Even locals. I find it a very useful phenomenon - because it allows me to know the noise floor of the receiver.

 

[tomservo]

I-10 goes under the bay in Mobile. It doesn't matter AM or FM. Both are entirely gone at the bottom of the tunnel. Even locals. I find it a very useful phenomenon - because it allows me to know the noise floor of the receiver.

Ah, you beat me to it. I pass through those tunnels regularly and both the Wallace (I-10) tunnels and the Bankhead (US-90/98) downtown are radio free zones.

Back in the olden days before Austal and all the industry sprang up on the east side of the Wallace tunnels, the WLVV 1410 tower was literally a hundred or two hundred feet from the mouth of the tunnels. Even with that proximity, the signal was gone as soon as you got part way into the tunnels.

If people are under the impression that radio signals are fine in tunnels, it's most likely because the DOT has installed some sort of booster or leaky coax to let signals in. I recall passing through interstate tunnels around Pittsburgh that didn't cause me to lose AM or FM signals but that is the only example I know of offhand.

Here in Mobile, I am not even sure all the cell phones work in the tunnels. I can't stream anything if I pass through with my Verizon service, but I can hold a phone call. There may be a cellular CDMA microcell or booster there that doesn't cover the LTE/700 MHz frequencies for 4G.

 

[semoochie]

When most people refer to a tunnel, it's a fairly short way through a hill. Examples of mile long or so tunnels are fairly rare, at least compared to the former. AM doesn't penetrate tunnels, PERIOD! FM does.

 

[KB1OKL]

If I get the chance, I'll see if I can do an A/B recording of my local AM station. They run a translator and play music most mornings, so if I can catch them doing tunes it should make for a good comparison between AM & the FM translator. Both are mono, both have basic processing. I have an AMAX AM stereo Sony Walkman for AM and I can use my Radio Shack portable for FM.

I'm so close to the tower that even on night power I get no whistle, whine or any other AM artifact so recordings always come out good.

Did you try the comparison Tom? I'm curious as to what you think.

 

[ContinuousWave]

When most people refer to a tunnel, it's a fairly short way through a hill. Examples of mile long or so tunnels are fairly rare, at least compared to the former. AM doesn't penetrate tunnels, PERIOD! FM does.

Depends on the length of the tower...at any spot in a tunnel where you cannot see the end of it (and thats a lot of them), FM does not penetrate..Tunnels usually have radiating coax for their two way radio systems to work with..if it was not there, there could not be any communications in/out..

 

[tomservo]

Did you try the comparison Tom? I'm curious as to what you think.

Not yet. It was dead air when I tuned in earlier. That sounds the same on either band.

 

[ContinuousWave]

Not yet. It was dead air when I tuned in earlier. That sounds the same on either band.

Not if there are lightning strikes nearby

actually FM hiss is different from AM hiss...even on a wideband AM radio...I have a Sony with switchable wide/narrow filters...on any local AM that is running decent audio levels, the wideband sounds great...

 

[kc4rae]

We have a station locally that uses a translator for its AM. The sound is quite different because it is being delivered to different sites by different means. The STL is pointed to the translator, which means the AM is probably on a ISDN or a web stream. They both are using a low pass filter and are both in mono, just not L+R mono. The processing is different as well.

 

[rbrucecarter5]

Not if there are lightning strikes nearby

AM HD drops immediately in a lightning storm. giving you the tail end of the strike when it drops to analog. It doesn't even take a nearby strike, it can be 10's of miles away and it will make HD drop. Given the recovery time, it is very annoying to listen to AM HD during a thunderstorm.

 

[Kelly A]

AM HD drops immediately in a lightning storm. giving you the tail end of the strike when it drops to analog. It doesn't even take a nearby strike, it can be 10's of miles away and it will make HD drop. Given the recovery time, it is very annoying to listen to AM HD during a thunderstorm.

I could swear you've been one of the longtime detractors for AM-HD and that analog AM is just fine, yet you don't like it when it switches from digital back to analog? So you DO listen to AM-HD? Better be careful, the anti-HD group will kick you out of the anti-anything-new club.

 

[rbrucecarter5]

I could swear you've been one of the longtime detractors for AM-HD and that analog AM is just fine, yet you don't like it when it switches from digital back to analog? So you DO listen to AM-HD? Better be careful, the anti-HD group will kick you out of the anti-anything-new club.

I actually have HD radios at home and in the car, because in Houston ALL interesting formats are ONLY on HD-2 FM. If HD plays something I want to hear, I use it - even with its limitations which are many and in my opinion will lead to HD's downfall. I look on the HD radios as temporary - HD will go away slowly like C-Quam did on AM. Houston no longer has any AM HD stations, the nearest is in College Station. So these observations are from memory when I lived in Dallas which still had AM HD stations. Even very strong local ones dropped immediately in thunderstorms.

As for the anti-HD crowd, I report observations on the shortcomings of the system. And there are many. I think it could be fixed or at least patched to work a little better, but not without some crow and humble pie eating by the HD engineers, who never admit mistakes. And unfortunately (for them) consumers have spoken, bad word of mouth spread, and the time has passed, the window of opportunity closed. IF there ever was a time or window in the first place, the system needed to WORK PROPERLY and have compelling content. At least Houston has the compelling content right, but the technical flaws even make a DX'er like me frustrated with unreliable reception. The average consumer? GONE at the first dropout, never to come back.

 

[JohnnyElectron]

Feedback about FCC / Kinetronic Labs meet?

Anybody hear any feedback about the Kinetronic Labs meeting with the FCC and if anything positive came out of it?

 

[KB1OKL]

As for the anti-HD crowd, I report observations on the shortcomings of the system. And there are many. I think it could be fixed or at least patched to work a little better, but not without some crow and humble pie eating by the HD engineers, who never admit mistakes. And unfortunately (for them) consumers have spoken, bad word of mouth spread, and the time has passed, the window of opportunity closed. IF there ever was a time or window in the first place, the system needed to WORK PROPERLY and have compelling content. At least Houston has the compelling content right, but the technical flaws even make a DX'er like me frustrated with unreliable reception. The average consumer? GONE at the first dropout, never to come back.

The biggest mistake that was made with HD was putting it on the existing AM and FM bands which essentially put it in competition with analog. There was never any clamor from anyone except the industry for a better AM or FM mode of delivery. ibiquity tried to manufacturer reasons why we would want it and they all rang false. Nope, no one cared, the only way it would have become successful was if it had been so much better than analog that no one could live without and it of course didn't even come close. It has so many technical detriments that it wouldn't have been successful even if it had been put on it's on band like in Europe where it has also consistently been a lead balloon even though it has been mandated by the government, no one wants it and no one cares. Next.

 

[kenglish]

The reason HD Radio (IBOC) was put in the existing AM/FM Bands ("In-Band, On-channel") was because most broadcasters were not willing to buy new spectrum (and, pay new regulatory fees).
20/20 Hindsight may see that as a mistake, or maybe not.

 

[tomservo]

The reason HD Radio (IBOC) was put in the existing AM/FM Bands ("In-Band, On-channel") was because most broadcasters were not willing to buy new spectrum (and, pay new regulatory fees).
20/20 Hindsight may see that as a mistake, or maybe not.

Even though it's been a tremendous headache, I can see why the broadcasters wanted an on-band solution. At the time this was being discussed, weren't the options for a new radio band kind of limited? I seem to recall talk of using the L-band, generally the 1452-1467 MHz part of the spectrum. That was thwarted by the military, which uses the band for telemetry. Getting the military to vacate spectrum is like pulling teeth. Here on the Gulf Coast the military was supposed to give up some frequencies so that T-Mobile could build out their 3G HSPA/HSPA+ network, but the government dragged their heels and stalled so long that we STILL don't have 3G service in many areas around here. T-Mobile would up skipping over that and going straight to their LTE (true(r) 4G) deployments to make up for lost ground. I think they finally started building out a supplementary 3G network in this area just last year, after the military was asked to vacate the frequencies back in the 90s!

DAB is also used on some other UHF and VHF (~200 MHz) frequencies around the world, but those are all in use here as well.

Then there would be the sudden change in the coverage model. We seem to be sort of unique in our setup where a strong central transmitter serves a metro area or region and that programming is not exactly duplicated nationally. Going to a high frequency digital setup would have required a cellular-like approach to coverage which would leave rural users out in the cold, especially if the network was deployed on the GHz bands.

I'm not really sure what digital alternatives we could actually use in this country that would duplicate analog coverage of individual stations and also increase the sound quality and variety of programming. Perhaps some sort of MediaFLO-like setup from reclaimed TV spectrum? MediaFLO is a now-defunct transmission system that both Verizon and AT&T used to provide 16 channels of live television without consuming their data bandwidth on cell phones. It utilized a single TV channel in the UHF band, IIRC. And much like our current analog broadcasts, it was a central (or dual) transmissions that covered only a metro area and surrounding areas. Maybe something like that could work for radio. 16 TV channels' worth of bandwidth would surely allow every station in a major market equal access. The hardware is proven and it should be a pretty robust setup that could easily be put back in phones and in car entertainment systems for minimal cost.

 

[xmtrland]

I work for an AM IBOC station and they do pay attention to the HD processing versus the Analog. They use a Nautel NX50 transmitter and an Optimod 9400 which allows you to process HD and analog separately. And as the transmitter model number indicates it's a 50KW station. From what I hear the HD performs well. The switch from Analog to digital is noticeable but levels are adjusted for a smooth transition. Next time we get lightning I'll have to see how that affects the buffering on the HD. It's interesting I can turn the transmitter off for easily 2 seconds with out losing the HD stream. You don't hear the pattern change.

Also interesting to note that the Nautel NX50 configured (Exgine card) for HD is the same configuration to do C-quam. It's just a matter setting a preset for it. No I have not done it, but from what I read it's there.

The NX50 running IBOC HD is also GPS locked. So synchronization of this type of transmitter is already built in.

 

[ContinuousWave]

Digital requires timing that analog does not....hence the GPS syncing.....HD also does buffering in the rcvr which is why you can turn off the signal for 2 secs or so...sat rcvrs are similar so minor bridges, etc do not cause loss of signal (but 4 lane overpasses can depending on vehicle speed)

GM has dropped HD from a number of makes this year because of the switching back and forth (which they said was distracting)...The rcvr must se the HD signal for 4-8 seconds before switching to the digital but can switch back to analog rather quickly...which in the long term POes the car owner...

I don't think the Nautels have the software installed to do CQUAM......one or two lines of code could probably do it but iirc Nautel was asked about that at a NAB or other show and said they did not offer that option...Harris is the same way (though an external exciter can be ran to do the CQUAM)

 

[semoochie]

The reason HD Radio (IBOC) was put in the existing AM/FM Bands ("In-Band, On-channel") was because most broadcasters were not willing to buy new spectrum (and, pay new regulatory fees).
20/20 Hindsight may see that as a mistake, or maybe not.

No, the reason it's in-band is because the only band the government would allot was where Sirius/XM is now, turned down by the broadcasters because it would require too many repeaters.