1330 KKPZ turned on their HD Radio signal this week.

1640 KDZR should follow soon. (Finally a music format in AM HD!)

How is that working with the directional signal? KPOJ apparently had some trouble with theirs.

Is 1640 still broadcasting in analog AM Stereo?

More unneeded noise added to the band.
Its a Mickey Mouse technology.

"some trouble"? How about "total failure"?

Who listens to 1330? Why do they keep the format they have?

1330 is owned by Crawford. It's a religious company that as far as I know doesn't dabble in other formats. It's interesting that you should mention a Mickey Mouse technology since the local Radio Disney is probably the next one to go HD.

Actually, Crawford does have stations that do formats other than time-brokered Christian. They have a few nostalgia stations under the moniker "Legends." They also have a few talk and sports stations.

ssssssTHEYsMIGHTsNEEDsTOsPRAYsTHATsTHEYsDIDNTsBLOWsTHE sMONEYsONsTHEsHDsSCHEMEsssssssssssssssss

KKPZ is sounding pretty good in HD. But when are we going to have an AM HD music format? I have to admit that I've listened to Disney Radio sometimes. They have a loud high-energy format that's very much like AM Top 40 formats of the 70's.

They were working on both stations at the same time so 1640 should be the next to follow

Here's a dumb question for you smart engineer types.

Will KKPZ now broadcasting in HD increase their range any, particularly at night? If so, will it increase their range by very much?

Thanks.

Herb

Here's a good question; is AM even listenable at night in HD? How about adjacent stations? How about signal stability on HD stations with lots of adjacent channel interference?

NAB seems to say nothing about this except "HD IS OUR SAVIOR!!!!" No good excuse or spin as to why most stations aren't in HD yet, aren't advertising it, aren't selling it, etc.

More bad radio pretending disaster = greatness!

Nope... AM HD is shut off at night, otherwise it would interfere with adjacent channels. This is a problem that the FCC is trying to sort out.
In general, the range of the HD transmission is less than the analog signal.

At this point, there is no nighttime broadcasting in HD. Broadcastin in HD shouldn't change the coverage of analog reception. While good analog reception is possible below the digital threshhold, most people are overwhelmed by noise before that point so digital coverage is likely to be an improvement under these circumstances.

There are bunch of unanswered questions. Either they don't know (which means they didn't do enough research), or they know and (its bad and) they ain't saying.
Any predictions what happens to KPDQ if KGO throws on HD at night?

digital works pretty well within the 60dbu contour of the groundwave. After that its gone. analog of course is receivable after the 60dbu area but as was said more and more subject to noise.

There is no data yet on nighttime performance on AM. Shortwave DRM signals which are digital only, no analog carrier which it is wrapped around, propagate similar to the analog.

digital signal robustness is selectable in the digital exciter. Many tradeoffs exist. The shortwave signals arent concerned about keeping out of the analog channel for instance. the ammount of redundant subcarriers is also selectable so night time operation could be workable and controlled were the co and adjacent channel interferance issue to be dealt with sufficiently. this is all still theoretical of course.

The HD signal is limited in coverage due to the existence of an analog signal. If that ever goes away, they should be able to get digital coverage out to 40dbu. At least that's what I've heard about FM.

All of that babble above indicates AM HD has some MEGA PROBLEMS.

Not good news if you own AM, and more credence to do what Canada is doing and having everyone abandon the near useless quasi shortwave performing AM band now!

It's like keeping record players alive, please!

Anyone have potential listener data yet? Specifically, are HD radios moving in numbers that might actually matter?

Up to this point there haven't been a variety of good HD receivers and some like the Radiosophy Multistream have been only vaporware so far. There are several good receivers for cars like the JVC KD-HDR1 but the main consumer receiver has been the expensive Boston Accoustics Recepter Radio HD. It's a first generation tabletop receiver and is picky about antenna orientation but works well once you make it happy. Several stations that are unlistenable analog FM hash in my office sound perfect once digital fades over the analog. The FM part of the receiver is actually very sensitive -- I can receive Reed's 10 watt station fairly well downtown. The AM part, well, not so sensitive.

The most promising consumer receiver right now is the Accurian (another tabletop) which will be sold by Radio Shack for about a hundred bucks after the rebate. They really need to make some inexpensive HD Radio tuners for people who want to add HD Radio to their home systems.

> Not good news if you own AM, and more credence
> to do what Canada is doing and having everyone
> abandon the near useless quasi shortwave
> performing AM band now!

I just don't see the AM band going completely silent any time soon because Clear Channel and other broadcast conglomerates have paid so much money for stations there. However, could there be a possibility that sometime in the near future, conglomerates owning more than one AM in a given market might run one station analog only and the other digital only, in the same way that HDTV is simulcast today? This would ameliorate the interference problems somewhat, perhaps enough to allow for 24 hour operation of the digital. Of course if they were to do this, they might as well have gone with DRM, which I would consider a better idea because it would not force the use of proprietary software and hardware in a broadcast system that is supposedly "free" to the listener.

In any event, even if broadcasters were to completely evacuate the AM band someday, other services will move there. Even the spectrum below 150 kHz is still in use today.

Happy Thanksgiving, everyone!

1640 was still in AM Stereo as of yesterday afternoon when I listened.

Having listened to 1330's HD signal, I think it sounds kinda odd. KEX's HD sounds quite a bit better at this point.

What are you hearing on 1330-HD, Dylan? Is the bass distorted? Do the highs sound rolled off? I don't have a HD tuner, but I'm trying to make a guess whether they have new processing for HD or if it is the same as they used before they put the HD in.

Note that many of the programs that KKPZ airs are mixed in mono. The quality of the source material also varies quite a bit because of the varying levels of skill and quality of equipment used by the various producers. Some of the programs are broadcast from cassettes.

The highs sound a bit distorted to my ears.

Something is just a bit off. It sounds almost too "digital", if that makes any sense.

Agree, I heard them this weekend and definitely had a high-end "crackle" sort of distortion, possibly due to multiple reencodings.

On a semi-related note, I happened to be listening to KEX when they shutdown HD for the night. It switched back to analog, but just after that there was a distinct snap-crackle-pop on the analog audio, I assume as the HD exciter turned off.

I had an opportunity to hear IBAC radio a while back and wasn't too impressed...audio sounded the same as the main channel, but with a lot of metallic compression artifacting within. This, also, was taking into account that it was on the HD2 feed on 105.9 so you have to account for narrower bandwidth.

Still, how the marketing execs can pass this off as being "CD quality" (or even "near-CD quality" for that matter) is beyond me. I have heard DMX channels, via DBS on a high-end Pansat receiver installed at a friend's house that easily trumps this.

AM IBAC, of course, sucks. No questions in my mind about that. I am still waiting for a station around here to get on the "Cam-D" bandwagon. If indeed it works at night like Leonard claims it to, I am surprised it hasn't gotten more national attention than the two stations that are using it currently. Seems a more...I dunno, "sane" approach to IBAC than Ibiquity's system. (Afraid of the dark.........)

Listening was (is) conducted in the aforementioned friend's car, with a Kenwood rig she received for her birthday. (Those of you who remember the first "HD Table Radios Go On Sale" thread may also remember me mentioning this earlier this year under my short-lived "motocross_and_muzak" handle.)

Needless to say we *did* get the grounding situation straightened out (inductive alternator & engine hum was reduced quite a bit so that was one big plus) but still drops out quite a bit driving downtown PDX, still much so that at times it's completely unlistenable. (CD players usually come in *very handy* about this time.)

Remember my old "digital SCA" rant? Case in point........

Basically I'd take satellite (either DBS & mini Ku-band dish or Sirius, at the very least) or analogue AM/FM any day over IBAC. "HD Radio", even though it actually describes the method by which it is broadcast, seems kind of dishonest (misleading) to me to describe the quality.

Ptaak:
I like my record players!!

On a semi-related note, I happened to be listening to KEX when they shutdown HD for the night. It switched back to analog, but just after that there was a distinct snap-crackle-pop on the analog audio, I assume as the HD exciter turned off.

What you may have heard was the station changing pattern. KEX runs a non-directional pattern during the day, and a three-tower directional system at night. When they change the pattern, the station actually leaves the air for an instant while the antenna system switches.

Why must they leave the air for an instant?
Could not the 2 additional towers be brought up to power gradually? I am picturing someone turning a large wheel or big crank. Or maybe a large frankenstien style copper knife switch?

Imagine switching about 1400 volts at about 33 amps.

The source of the energy is one transmitter, not three.

Separate matching networks for each mode and tower.

The transmitter output gets interrupted while at least eight 240-volt solenoid-operated switches change direction.

They could have some large air wound RF transformer coils with a motor driven intercoil coupling adjustment that would either closely couple the coils for full power transfer into the 2 other towers at night, or for daytime, it moves the secondary coils far away from the primary, and rotate 90 degrees for zero coupling/power transfer.
This would eliminate need for all of those 240Volt solinoid operated switches and also would avoid having to interrupt the program.

Yeah 62, that makes a lot of sense. Let's install some huge Rube Goldbergesque contraption to save two burps a day at pattern change time.

Indeed why bother with AM at all?

Does anyone tolerate how noisey and unlistenable AM is these days?

How does one hack it after listening to all the digital on computers and Ipods or even FM?

It is REALLY bad with all the extra computer interference and all the old stuff like dimmer switches, power lines, etc.

The radio stations should hire a team of eco-protesters to go around to everyones house and replace all of the lamp dimmers, computers and other electronic stuff that needlessly radiates RF noise pollution. Kind of like the disconnect your downspout program.

And get the Cities to stop using LED signal lights and electric trains and busses while your at it too! Gee I bet hybrid cars make AM impulse noise too! Can you get people to stop buying those??

That'll save AM!

If AM just shut of the noisy analog and broadcast ALL DIGITAL we would alleviate the noise problem and have better digital audio quality as well... and you would no longer hear the adjacent channel hiss!

Time to go to radio shack and buy your $99.00 IBOC radio!

I'm sorry but the majority of my analog AM radio listening is a perfectly fine experience.

Don't know if the engineers working on KEX have made additional tweaks as of late, but I've been nicely surprised at the diminished hiss on some of my other radios.

The Delco is flawless, completely dealiing with the IBOC. Tried a coupla other radios recently and it's better!

(Or I think it's better, I wanna know which it is!)

Less than 5 percent of my AM listening is plagued by these things. Usually it's when I have to drive down town, then it's only in a few annoying areas. The rest of the time, the AM is just fine.

I've noted quite a few LED signals that do not make much of an RF mess at all. Perhaps construction of those is improving?

Also I've noted two kinds of LED lighting on cars. One kind is pure DC, always on. These are no problem at all. The second kind is a 60Hz impulse lighting.

These are distracting on the highway because they leave image prints on my eyes when I scan the road. IMHO, there is a strong case for not allowing these going forward. Too many cars with these put night time drivers at more risk for only a small return in service life on the light itself.

Older LED flashlights also pulsed. These make AM noise. Newer ones appear to just run on DC, and make only the usual on / off impulse any lighting will make. Non issue.

Perhaps our super-bright LED tech is improving as well?

The impulse system used to be necessary to achieve peak brightness and service life. I'm not sure that's the case now.

Not much we can do with the tram, but it's a highly localized issue, IMHO.

As has always been the case, some regard for the spectrum when building things, lets AM continue as it always has.

Given these things, I'm not sure there is a case for IBOC on the basis of a diminished listening experience alone.

It all still remains a content issue. Fix that and the other issues will work themselves out. Don't fix it, and all the quality in the world won't matter one bit.

BTW: Does the IBOC perform well next to the tram?

<quote>What you may have heard was the station changing pattern.</quote>
Nope, there was no interruption of the audio, just a few crackles.

What tram are you talking about? The one OHSU is putting up?

I didn't notice just how much noise is in the AM stations I listen to until I got an HD Radio. Once KEX digital fades in, it all just disappears. My brain has just been ignoring it, I guess. I'm looking forward to Disney Radio turning HD on so I can hear how well it does with music.

Won't be in stereo from what I understand.........meanwhile, according to FCC regulations, since DZR's in the Expanded band (1610-1700kHz) it has to be in stereo, so there's another advantage analogue AM has over IBAC!!

I could make a list if I had to..........

If there were a reliable and cost-effective way to do pattern changes without dropping carrier, somebody would be doing it by now. The engineering problem, in addition to the high voltages and currents involved, is that all of the different antenna pattern configurations have to present a proper electrical load to the transmitter (50 Ohms). The motorized variometer setup that is described in 62kgw's post would require that all of the coils move together in a precise manner so that the transmitter sees 50 Ohms throughout the pattern change operation. It is just a lot easier and more repeatable to turn the carrier off, flip the switches, and turn the carrier back on.

What do you mean it won't be in stereo? Why wouldn't it be in stereo like every other AM HD Radio station?

Exactly what I said--from what I understand it won't be in stereo because AM IBAC (Ibiquity's system) doesn't support stereo. (FM does, AM doesn't.)

As I am aware the only AM IBAC broadcast system that actually *does* support stereo is Kahn's Cam-D gizmo. But as I am further aware only two AM's in the entire country are actually making use of that system.........

Well, to be perfectly fair, the Ibiquity system does do stereo. It's just lacking a serious enough bit rate to do it properly. Mono signals are better on the artifacts than the stereo ones are.

Scowl, he means the analog wont be stereo any more. the HD will be in stereo of course.

Notalent he meant (until KBBT/KSKD cleared it up) that the IBAC wouldn't be stereo because he thought the system didn't support it.

Now he is retracting his statements..........

Analogue AM signals 1610 thru 1700 currently have to be in stereo because of FCC regulation (will cite number once I can remember which one it is.)

This may likely change tho, if AM Ibac actually becomes popular (can't see it happening due to technical limitations, and Ibiquity's seeming fear of night-time) and analogue X-band's stereo mandate may be lifted or at least loosened up, then the analogue signals may (will) likely not be stereo any more, or at least not very many will be stereo.

Have to wait and see what happens...........

"Well, to be perfectly fair, the Ibiquity system does do stereo. It's just lacking a serious enough bit rate to do it properly."

Reminds me of stereo laserdiscs vs. AC3, but in that case it was actually a matter of implementation.......

How much bandwidth would stereo AM IBAC require to make it worth the trouble? 96k? 128, what??

(But in terms of MP3 recording, I still say 320 whoops ass of anything lower any day! Not sure if it could apply to any current IBAC implementations, AM or FM, tho..........)

mp3 coding and the coding used in HD are entirely un comparable. It would take 48kbps to make good sounding AM IBOC, 64 would be excellent, 96 would be pristine.

these bit rates could only happen on AM without the presence of the Analog information.

Oddly the AM IBOC codec will not allow mono implementation. you can feed it a mono signal but it will code with a stereo codec thus there is no benefit to being mono since it will just turn it into two identical channels.

When I plug my headphones into a mono receiver, it also turns it into two identical channels. I guess the damn things don't allow mono implementation! :-)

Seems to me, there would be some redundancy there possible on the receiving end. Two identical channels, would allow for a lower number of error correcting bits. Doesn't the Ibiquity system support doing that?

Thought it did anyway...

KEX is in Stereo on it's HD channel, although the only time I hear it is during Mark and Dave. A few sound effects here and there. That's about it.

The Ibiquity system was intended to provide consistantly reliable audio regardless of what's in the audio. That's one of the major goals of digital broadcasting. It wouldn't be acceptable for it to suddenly fail during a stereo commercial in the middle of a mono talk show.

How does AM IBAC sound in Stereo (in terms of listening to stereophonic sound, not a stereo broadcast of mono?) Is it as "watery" and "metallic" sounding as its FM counterpart? More/less??

Seems to me that because AM isn't line-of-sight, it would seem to fare better in my friend's car especially driving downtown. (Forgot to mention earlier: the dropping-out was all on FM.)

Might prove to be a tad problematic listening to it in a building (like an office tower or basement) tho, areas that might otherwise easily be penetrable by FM.........

Aside from the problems listening on a car stereo (that we've heard anyway, not sure about the experiences of others here using this same system) do car systems generally work better than fixed (i.e. "at home") IBAC radios?

I want some honest opinions and general ideas on what works/what doesn't work before I try making the investment in a IBAC rig (if I ever do) 'coz I am on a reeeeeeeally tight budget...........

> The Ibiquity system was intended to provide
> consistantly reliable audio regardless of what's
> in the audio. That's one of the major goals of
> digital broadcasting.

In practice, codecs used for digital audio and video fall short of this goal because certain types of content can be compressed into the alloted bandwidth more easily than others. The designers of these codecs have to make tradeoffs in order to achieve really high compression ratios.

Yes, codecs will generate artifacts when they can't compress well enough, but codecs aren't designed to handle data loss and error correction which is what the question was about.

Actually, there is significant error correction in the Ibiquity system. Both digital sub-carriers carry a redundant signal.

This correction ratio is adjustable to trade for bitrate. I've no data on the actual choices made.

IMHO, it's a fairly solid system in this regard.

The core problems of AM remain however. Excessive noise is gonna bury pretty much any signal. That's why I asked about the light rail performance.

Night time brings the problem of keeping things in phase as well.

Hello to all.
Please go over to the other KKPZ HD thread and add your comments! Or should I say KKPZzzzzzzzzzzzzzzzzzzzzzzzz!

Yes, there is significant error correction in the Ibiquity system, but it all happens before the data reaches the codec which needs a perfect bit stream to work.

Can someone out there with an old radio that has a decent s-meter and narrow filter and analog fine tuning do some measurements? (Like one of those big Hallicrafters Ham/SW radios or similar.)
Some of us think 1320 and 1340 are less powerful than are 1180 and 1200 in relation to 1330 and 1190 respectively. Is that true? Why would 1330 not crank up the HD sideband hash as much % as does 1190?
Tune to the main carrier and note the sighal level, then find the noise peaks on the + and - sidebands and note those readings. Repeat for the other station.
Thank You

One station runs 1/10th the power of the other one. That could have something to do with it. KEX's antennas are also broad banded and about halfwave.

62kgw:
I just tried the measurement that you proposed above from Hillsboro, using my Icom IC-R8500 connected to a 100 foot "longwire" antenna.
Couple of things, the S meter on the 8500 is quite small, although it IS an analog meter (reading error could be a db or 2 for each measurement). The 8500 is a digital box, BUT it can tune (with a knob) in steps as small as 10 hz. The "narrow" 2.2khz filter was used. In addition, I used a 20 db attenuater on KEX and a 10 db attenuator on KKPZ as an attempt to get the signals to about the same level.

results:

KKPZ
1317 S-9 +10 db
1330 S-9 +35 db (average)
1343 S-9 +11 db

KEX
1177 S-9 +17 db
1190 S-9 +40 db (average)
1203 S-9 +17 db

So, I would conclude that the main to HD ratios of the two stations are fairly close, with the possibility that KKPZ might have slightly weaker HD (compared to the main signal).

As I tried to explain, I am looking for data on the amount of HD hash RELATIVE to the main carrier.
If someone can go to a position where the received signal strength from both stations is the same (obviously closer to KKPZ's antenna tower), that would make it easy to measure and compare the sideband differences. A modern general coverage receiver that has meter with good resolution could be used.

JR, your ahead allready. Great! Anyone else? The more data the better!

why bother?

there is a mandated spec for the power in the sidebands.

they should both be the same relative to their respective carrier.

you are not going to find any evidence of a conspiracy using a radio either. you need a spectrum analyzer for that.

they exist in the pdx market and surely qualified engineers have checked to be sure 1330 is operating correctly or they would not have been authorized to turn it on.

a spectrum mask showing the occupied bandwidth should be on file with the FCC as part of the IBOC authorization and should also be in the public file of the station.

Why dont YOU go do the research YOURSELF??

OK then, do not make any measurements, don't listen for noise, and do not make observations about sound quality. Just listen to the program and patronize the advertizers.
If you are not in the 25mV area, don't listen, period!

9:15 PM tonite 1330 +/- = Bzzzzzzzzz ssssssssss xxxxzzzzzz ssssssssszzz, etc.

Noticed that they were testing HD this morning before official "sunrise", which is 7:45 for Dec, in Portland.
From Hillsboro, last night, there was so much DX stuff on 1340 (and perhaps 1320 as well), HD indicator would blink, but radio would not lock on... saw PAD info, but did not get digital reception.
I think they turned the HD off before midnight.

Was it intentional testing or a error?

I heard 1330's HD on the air at around 11:50 last evening.

The HD is still on as of now.