Lightning 'taking out' an AM IBOC/HD Radio Signal, KMKI 620 kHz

[bentleyontheair]

im sorry to say this but KMKI AM should have kept broadcasting in C-QUAM Stereo like they did a few years ago i had a portable cassette Walkman that received am stereo and sounded the best i have ever heard, in my childhood. and bragged about it when i was in the 1st grade, and they didn't believed it until they heard it themselves, so long story short... they should have kept broadcasting in am stereo

[OXLEYCRUSHER]

Can't see the point of having HD on AM,FM is more suitable,and less affected by lightning discharges.

[Hiphophero107]

This sounds like WKMI 1260 in Boston.

[superarticulation]

Could you explain what's HD AM signal? Is it analog better than AM stereo or digital signal like DRM+?

[aurora990]

as long as it is on the AM radio band, AM radio station reception can suffer from electrical interference including AM radio station HD reception. From what I know, HD radio reception from any AM radio station is more sensitive than standard AM radio reception.

[uploadJ]

@aurora990 -

Tnx for the comment. As to AM IBOC, by definition, it is in the AM 535-1705 kHz band, whereas FM IBOC is, of course, on the FM 88-108 MHz band.

I suppose I should do a 'range test' on KRLD and note the difference between standard AM transmission and their AM In-Band-On-Channel -IBOC digital transmission ... but I think the results are going to show that the IBOC digital transmission is weaker, owing to the way 'things' are presently configured (IBOC being at a lower power).

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[aurora990]

@uploadJ you are welcome. I prefer standard AM radio than HD AM radio until HD radio is available in all places besides large cities and HD AM radio reception is almost interference free.

[gccengineering1996]

That sound quality from that AM station sounds good in HD. I used a loop antenna, but WCBS-HD will not come in. Question how far KMKI-HD from your listening location so I see if I have to be very close to the station or use a better antenna.

[uploadJ]

@gccengineering1996

KMKI is not all that far away from me, less than 10 miles or so, and with the highly conductive soil we have (30 ms in the Collin and Dallas County vicinity) I have really a fairly strong signal from them.

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[ender06026]

I picked up a SONY XDR-S3HD for 39 bucks when Best Buy had a few lying around after they were discontinued. It would be very nice if they allowed the user to toggle off the HD feature. Distant stations with HD content can cause it cycle through the process of acquiring the HD signal, only to drop back to analog randomly as propagation shifts. This is nicely shown in your video as lightning disrupts the data stream and causes your receiver to drop back to the analog signal.

[gccengineering1996]

Update: I am getting an HD-100 soon off the net soon, I just bought a NS-HD01 because it was $50, the sound quality is good, I am just getting ready for modern AM DX this year. BTW, great demo on the HD-100 on how it handles thunderstorms, There is one station in HD here where I live that is on 1230 kHz, and I ready to hear it soon.

[iceboxxman]

AM sucks no matter how they try to cobble it up - you can't polish a turd .

[briank101101]

A lot of people here are judging the sound quality based on a camcorder microphone picking up sound from speakers that likely don't have a flat frequency response. HD AM stations that broadcast using pristine audio source material sound pretty darn good. In stereo they have 38 kbps to play with, using a codec that uses Spectral Band Replication and parametric stereo, which is better than a good 40 kbps AAC+ web stream as the audio only has to go up to 15 kHz

[uploadJ]

Re: Sound quality, have you viewed the vid made of the marching band with the Canon S3 IS camera titled "S3 IS Sound test".

Electret microphones have an intrinsically wide and flat response range.

Having said all that, I am sure the posters here are basing their observations on their *own* real life listening tests with actual IBOC receivers.

Keep in mind this was a demonstration of lightning effects on IBOC.

Thank your for your observation and post.

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[HWGuyEG]

@uploadJ

Good camera, I have one, too bad many have that display bug.

[EncoreEnterprisesLLC]

Why did you leave out the guy's name at the beginning of the video?

[uploadJ]

I don't want to give his full name.

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[samljer]

Most non-digital stations can sound that good on a good stereo, im not impressed

[gccengineering1996]

Great, So if the station was digital only that means it would knock out completely during a thunderstorm and then come back on. Not good at all even during severe thunderstorms during the summer and hurricane watches and warnings. this is a big problem for AM and Biequity for failed , questionable, quacked up to be technology.

[JoeOnTheRoad]

I've got to say it does sound pretty good when it switches to Digital.

[uploadJ]

Yes, I've got to say it does too.

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[Lachlant1984]

I know I've said this before, but I strongly disagree with that statement, yes there's not a lot of treble in the standard analogue AM sound, but it just sounds a bit more full bodied and not compressed and sterile like the HD sounds like, but that's my opinion.

[uploadJ]

Lachlant1984: "I know I've said this before, but I strongly disagree with that statement"

I think the comment the other poster made was in regards to the AM mode that can accompany IBOC; in particular, KMKI (this radio station) had the audio 'cut off' at 4.7 kHz until this year, when they 'widened' it.

A number of us are aware what a full-bodied 10 kHz BW AM station sounds like ... for instance, I have a wide mechanical filter in my Heathkit AR1500 that allows good rendition of AM.

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[Cringle84]

@uploadJ True, I have a Sherwood TD130SB tuner, containing AM STEREO, and noise blanking chip, the sound quality is crisp being wide band, and listening on a stormy night, well you can still hear the lightning, but you can only just hear it, and 50 Hz hash noise from fluros are completely blanked out, but one thing it does not stop is computer interference and heterodyning and chirps from strong adjacent stations.

[Lachlant1984]

What brand of radio is that you're using in this video?

[uploadJ]

A "Radiosophy HD100"

Not a bad little radio really ... I borrowed it from a friend for some tests, like this.

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[amstereofan]

A much much better system for AM and FM than DRM which will never get anywhere. IBOC really would be a great idea for Europe and the UK

[marsam233]

HD Radio is terrible on AM. On FM it is not the greatest, but it is better. I'd hope the people in Europe and the UK, would not adopt HD Radio, you guys would throw it out quick.

[eimac4x1]

So this "high tec" digital has to fall back on old fashioned analog to work? Whats the point? And the regular AM mode sounded better, anyway.

[deconstructionist67]

Is the AM HD stereo?

Some DRM broadcasts on SW are.

[uploadJ]

Yup; AM "HD" ... also formally known as Ibiquity "IBOC" (In-Band On-Channel) format ...

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[bratina501]

Well, both yes and no it depends on which station you listen to. Like DRM, its up to the broadcaster to decide whether they broadcast in stereo or not. I personally have heard the digital stereo aspect on both AM and FM as I have been an HD Radio listener since December of 2006.

[uploadJ]

I will listen closely to Radio Disney and see if they are Stereo.

There are some trade-offs for AM when doing IBOC simulcast with the AM signal, and I don't recall specifically what Ibiquity's standard will allow for IBOC. FM of course is a different story: they have a lot more BW (bandwidth) to work with.

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[bratina501]

I think that AM IBOC has two modes, a core mode at 20 kbps mono and 32 kbps stereo depending on your reception. Radio Disney is also available in my area in digital on KDZR 1640 which like KMKI broadcast in C-QUAM AM stereo originally. In my case KDZR switched in the spring of 2003 and at the time I had a Sony SRF-42 HIFI wide band AM stereo radio only Walkman and they sounded incredible especially at close range. My current Accurian also gets analog AM stereo through a firmware Easter egg.

[staticbear76]

i love hearing the staticy crackle on my am radio it is one of lifes simple pleasures

[uploadJ]

Me too, I like hearing the occasional lightning crackle; lets one know there is a storm/rain in the area too!

[tornadoguru6]

I do not have that problem and it is lightning right now!

[uploadJ]

tornadoguru6: "I do not have that problem and it is lightning right now!"

As this observation stands, without indicating which market you are in, how far away T-storms are indicated, I don't know how one would evaluate your claim.

At the moment, in the DFW area, KFWS WSR-88D doesn't indicate any precip that would be capable of producing lightning, so, I have to asume you are outside the Dallas/Ft. Worth area.

If you get a chance, please document your obs & conds with data, pics, etc.

[Ubstudios]

I have to say even though this showcases a flaw in the technology, it is still damn cool to hear lightning take out HD.

[Lachlant1984]

If you're in an area where radio reception is poor and you can only just get HD signals, would simply moving around the room cause the HD signal to drop out as sometimes happens with FM?

[uploadJ]

Not so much with AM, but if you come near a digital appliance, like a computer, the RF noise produced in close proximity to the computer can wipe out an AM Broadcast signal ... and that's why I keep my IBOC Sony across the room from the PC.

[Lachlant1984]

That music sounds better when the unit isn't receiving the HD transmission. It sounds shit in HD, like a highly compressed MP3 file.

[uploadJ]

Lachlant1984: "That music sounds better when the unit isn't receiving the HD transmission"

Yes, the 'coding' they use sounds bad esp. at the higher frequencies. Even 50 kW 820 kHz WBAP when they were IBOC digital sounded 'processed' to the point of being objectionable.

[Lachlant1984]

Let's say you're listening to your favourite radio station, the normal analogue signal is good, but there's something wrong with the HD transmission. Is it possible to force these radios to receive the analogue signal only even if you're in an area that broadcasts HD? Does that annoying blue flashing light on the front of the radio indicate whether the radio is receiving HD or not? I wonder how adverse weather conditions will effect DAB+ Radio?

[uploadJ]

Lachlant1984 "Is it possible to force these radios to receive the analogue signal only even if you're in an area that broadcasts HD?"

There was a well-written webpage on

the Sony XFR-F1HD (that I also have) on getting it to do 'other' things like this.

[wildbilltexas]

Back in the early 90's I visited KWFT in Wichita Falls while job hunting. Their studios were out in the transmitter building with little or no sound proofing. It was like working in a garage. It's sad there is only one AM left in that town.

[marsam233]

I thought HD was supposed to take care of this sort of thing. Guess that's another lie put forth by Ibiquity.

[Amishman35]

I wish they would bring back analogue AM stereo. I head a video of it, and it sounded even better than the digital version, even if they both were in mono.

[uploadJ]

The 'chirp' that can be heard three (or four?) times is a pet cockatiel demanding attention ...

[bradmann85]

i had one that would let you know that its his bed time usually at 9pm and he wont quit till you cover him up.