HD Reception in New England

[rbrucecarter5]

They said medium market, Dallas is a large market at #5. KMKI is a flamethrower, they have listeners up to 300 miles away in Lubbock, substantial enough numbers in Abilene 180 miles away they have done remotes from there.

KMKI does not get "numbers" in Abeline and barely makes the book in Dallas, where it's had a 0.1 share and a cume of around 30,000 total weekly listeners over the last year or so.

And it is hardly a "flamethrower" as it does not even put a 5 mV/m signal over the city of Dallas or over the city of Ft Worth; in noisy metros around 10 mV/m is needed to generate any ratings results...

Remember, this was the old KWFT from Wichita Falls, and it's directional away from Dallas and Ft Worth, even in the daytime.

Well, its Abilene, not Abelene - and they were the ones doing the remotes - I'm just stating what happened. I found at least ten listeners in Lubbock - in one neighborhood - without even trying at all. They may have been KWFT, I remember KWFT - but they changed their COL to Plano, and put in brand new - no compromise - quarter wave towers. The pattern is different, it favors West and North. They definitely qualify as a regional flamethrower - virtually static free in both Midland and Lubbock before they went down the HD wormhole - even better than KLIF 570 and WBAP 820. Only KSKY 660 makes it out to West Texas better, and that is only after they went 20 kW and KMKI downgraded to HD. KMKI protects 610 Houston, but at least North and West they really get out. It is like other regional flamethrowers - KGNC Amarillo, which equals KEEL in Dallas, often overriding it in the daytime. And WNAX Yankston is another regional flamethrower up in SD. There are stories of others - 5 kW monsters that go and go and go. KMKI is up there with the best of them, even with HD they still have amazing coverage, not as good as before, but very impressive. Try them sometime when you are in Texas, they are impressive!

 

[KB1OKL]

Analog tuning results with AM HD are very interesting. One time, Dallas local KMKI broadcast dead air in HD, so I did some recordings of the station while I tuned up and down slightly off frequency. What was immediately apparent is that the 5-10 kHz phase modulation only mutes if your tuning is dead center. Even slightly off frequency, the phase modulation degrades into amplitude modulation and sounds like pink noise. It is so sensitive, I doubt that even the digitally tuned radios can get it perfect enough - the circuitry generating the tuning voltage for varactors consists of a digital to analog converter (DAC), and most of them are 10 to 12 bits. That wouldn't be exact enough to eliminate this problem completely, and even if it was varactors are not linear enough to tune exactly center frequency on every AM station across the band. You will hear some degree of noise coming from the 5-10 kHz phase modulated sidebands. And all of that doesn't even take into account the phase response of the AM station's antenna array, which could probably vary several degrees over the HD bandwidth. Bottom line - HD self noise on AM is a huge problem, and phase modulating 5 - 10k assume perfect center tuning.

Let's talk about exact center tuning for a moment. I was able to center the tuning fairly easily, using the HD self inteference "rush" as a guide. When I got the tuning perfectly centered, a secondary effect arose - a weird warbling sound. I can only assume it happens because the sidebands are not perfectly symmetrical - something inherent in the transmission scheme, or perhaps due to the IF response not being perfectly symmetrical.

All of this - except HD rush 1 kHz or more from the center frequency - would be inaudible to a listener when program material is present. But this points again to bad engineering at iBiquity, it shouldn't be the job of listeners to find these problems which should have been discovered in the lab before the system ever went public. A good engineer would not have made the assumptions (1) tuning is perfectly center frequency and (2) IF response is perfectly symmetrical. They should have tested both scenarios and designed a system that works when center frequency is a little off, and IF response is lopsided.

You wouldn't believe the noise on WBZ with WBZ tuned dead center at night, with KDKA and WINS spewing hash in addition to WBZ's own hash it sounds like there's a diesel generator chugging in the studio right behind the announcer when using an analog radio, wonderful system.

 

[iyiyi]

1030 sure sounds great in HD!

 

[KB1OKL]

1030 sure sounds great in HD!

I think it sounds like krap in HD, the voice on my Tom Tom sounds more real than the announcers do on WBZ-HD (during the rare occasions I actually got a lock).

 

[davideduardo]

Well, its Abilene, not Abelene -

The spelling police generally tend to conveniently forget that 8% of Americans have some degree of dyslexia. Thanks for allowing me to again (which to me looks identical to "agian") remind folks that there are many of us who can't see certain types of typos or spelling mistakes, particularly with words with caps at the start which spelling checkers tend to ignore.

 

[rbrucecarter5]

Well, its Abilene, not Abelene -

The spelling police generally tend to conveniently forget that 8% of Americans have some degree of dyslexia. Thanks for allowing me to again (which to me looks identical to "agian") remind folks that there are many of us who can't see certain types of typos or spelling mistakes, particularly with words with caps at the start which spelling checkers tend to ignore.

I'm dyslexic myself, so I can relate. I started being dyslexic when the schools abandoned phonics and started the look say method of teaching reading. Prior to that, I could read and spell very well. Being dyslexic leads to some interesting confusion on call letters, which are all caps. I had to put station call letters in 6 inch high capitals when I was on the air, or mangle legal ID's. I cannot spell words verbally to others, which made getting the call letters right each time extremely difficult. I've learned coping skills, probably you have too.

A young friend of mine has helped me open up about my dyslexia, which I hid for years out of shame. I met her when she did commercials for a company I worked for. Her name is Bella Thorne, and her advice to me - yeah a kid teaching an old dog new tricks - was just to read as much as I can, no matter how hard it is. That is how she got better, but it is a struggle. Here is her story along with others:

http://dyslexiahelp.umich.edu/success-stories

 

[K6JHU]

For abut 35 years I taped (later MP3) text books for Recording for the Blind (RFB). Then they found out that most of the students requesting the books were dyslexic so it became RFB&D. It was interesting every year to go to the annual meeting and see the sucess stories of those who completed school (including graduate school) even with dyslexia. Try taping a programming manual

 

[spunker88]

1030 sure sounds great in HD!

Decide for yourselves, this is via skywave so it may not be the best sample. I have an aircheck of WBZ in HD for several seconds with its very artificial sounding treble. As soon as the HD drops, the audio gets narrow but I notice instant relief on my ears. Meaning I would take the 5khz analog signal over the 15khz digital signal. If it were a full bandwidth analog signal there would be no competition.

http://users8.jabry.com/spunker88/Temp/wbz_hd.mp3

 

[iyiyi]

1030 sure sounds great in HD!

Decide for yourselves, this is via skywave so it may not be the best sample. I have an aircheck of WBZ in HD for several seconds with its very artificial sounding treble. As soon as the HD drops, the audio gets narrow but I notice instant relief on my ears. Meaning I would take the 5khz analog signal over the 15khz digital signal. If it were a full bandwidth analog signal there would be no competition.

http://users8.jabry.com/spunker88/Temp/wbz_hd.mp3

Excellent audio recording! Very good HD/Analog A/B test! Kind of blows a hole in the "no HD skywave lock" mantra, yes?

Show me just ONE analog MW signal that sounds so crisp and bright. If you are unable to detect the superiority of the HD over the analog in your audio clip, I seriously suggest that you consult an ear specialist. Just a tap of the treble control can adjust that audio brilliance to any acceptable level. I'm glad that they punch the highs on the HD eq. It showcases the quality and capabilities of HD quite nicely. HD is saying to analog, " I can hit these high notes, how's about you?"

I'll wait and see if somebody can produce an aircheck of an analog signal even remotely close to the clarity and brilliance HD shows in your audio example.

-

 

[KB1OKL]

1030 sure sounds great in HD!

Decide for yourselves, this is via skywave so it may not be the best sample. I have an aircheck of WBZ in HD for several seconds with its very artificial sounding treble. As soon as the HD drops, the audio gets narrow but I notice instant relief on my ears. Meaning I would take the 5khz analog signal over the 15khz digital signal. If it were a full bandwidth analog signal there would be no competition.

http://users8.jabry.com/spunker88/Temp/wbz_hd.mp3

Excellent audio recording! Very good HD/Analog A/B test! Kind of blows a hole in the "no HD skywave lock" mantra, yes?

Well, he did say several seconds which is just about all I was able to get also.

Show me just ONE analog MW signal that sounds so crisp and bright. If you are unable to detect the superiority of the HD over the analog in your audio clip, I seriously suggest that you consult an ear specialist. Just a tap of the treble control can adjust that audio brilliance to any acceptable level. I'm glad that they punch the highs on the HD eq. It showcases the quality and capabilities of HD quite nicely. HD is saying to analog, " I can hit these high notes, how's about you?"

Yes they can hit those ARTIFICIAL high notes that sound as grating as fingernails scratching a blackboard, they sound terrible, i could not listen to it for more than a minute besides the fact that HD won't stay locked anyway.

I'll wait and see if somebody can produce an aircheck of an analog signal even remotely close to the clarity and brilliance HD shows in your audio example.

I don't have any air checks but there are some analog AM's that sound great with the 16kHz position on my r-390, wide-band analog AM sounds much better than AM HD.

 

[iyiyi]

Couple of other HD/analog comparisons in the WBZ aircheck. Far superior signal/noise ratio in HD. Night and day difference between the spacious dynamic range of HD vs the compressed, flat audio of the analog. Continuous audio levels in HD vs the rise and fall of analog audio with signal strength variations. No limit on frequency response, up to the designed parameters, of HD. Analog OTOH, needs to equalize or otherwise process it's audio in an attempt to compensate for poor receiver IF response, transmitter and antenna system deficiencies, uses heavy compression to provide maximum S/N ratios - yet for all that, background noise increase is still a function of distance from the xmtr.

Oh yeah... Seems like nobody noticed the perfect, seamless segue from HD back to analog when the signal deteriorated. Also the fact that the aircheck was stopped just as soon as the analog audio went over the cliff into static...

One could get the impression that digital technology has improved just about everything except radio...

-

 

[rbrucecarter5]

No results on WBZ from Houston - not even the analog signal was present. I am not too surprised - WBZ used to be easy to get in Texas, just null the 1030 in Casper. But since they converted to HD, nothing - analog signal is gone.

 

[Savage]

If anyone actually thinks that aircheck of WBZ-HD sounds good, he needs his head aligned. It sounds like a cheesy, chorusing, ringing low-fi web stream. I vastly prefer the analog - even strangled back to 4.7 kHz (if the analog were opened up to the permissible TWICE as wide bandpass I would like it even better.)

At least the voices sound human in analog. As opposed to the HD digital "Mr. Roboto in a sewer pipe" effect. It's a poor tradeoff for an intermittently-disappearing low noise floor.

And you honestly think any normal civilian listener would put up with the mode-hopping? I don't. And I've been doing this for 45 years. I know what people will put up with, and what they won't, and believe me - this represents the latter.

 

[spunker88]

Its pretty easy to get WBZ to lock in HD at dusk here. It sits directly towards the east of me meaning it gets the effects of skywave before other stations do. Later at night adjacent interference from KDKA and some from WHO make it much harder to get a lock.

While the HD signal may be able to reach a higher frequency its very artificial sounding and would lead to listener fatigue quickly. The analog signal sounds more pleasing to listen to, even though its half bandwidth of what analog AM is allowed (5khz as limited by IBOC and the receiver XDR-F1HD). Yes, it cuts off all the treble but it sounds a lot smoother and would sound even better if it were not limited by the lossy 128kb/s MP3 I encoded it in.

AM stereo sounds better than HD Radio any day of the week, listen to this. Sadly this station switched to sports.
http://www.youtube.com/watch?v=amr43lL1UW8

Also if you want to hear a mono station that matches the treble response of HD without sounding artificial in analog listen to this aircheck of CHML.
http://www.youtube.com/watch?v=O15zCXo2D-U

Granted anything you hear over the internet has likely been compressed into some lossy audio format, so its hard to compare without hearing it live in person or using a large uncompressed file type like wav or flac.

 

[spunker88]

If anyone actually thinks that aircheck of WBZ-HD sounds good, he needs his head aligned.  It sounds like a cheesy, chorusing, ringing low-fi web stream.  I vastly prefer the analog - even strangled back to 4.7 kHz (if the analog were opened up to the permissible TWICE as wide bandpass I would like it even better.)

At least the voices sound human in analog.  As opposed to the HD digital "Mr. Roboto in a sewer pipe" effect.  It's a poor tradeoff for an intermittently-disappearing low noise floor.

And you honestly think any normal civilian listener would put up with the mode-hopping?  I don't.  And I've been doing this for 45 years.  I know what people will put up with, and what they won't, and believe me - this represents the latter.

I was listening to a football game on WFAN one night not too long ago because it wasn't on TV and all the internet streams are blacked out. Unfortunately WFAN left their HD on and it quickly became annoying because it kept going in and out of HD randomly. Sure I could listen to it on any older non-HD radio but then I would have to deal with the HD noise that overlaps the analog audio on older wide bandwidth receivers.

I find the low noise floor of HD annoying. Its the same as cell phones, I was put on hold on my cell phone the other day for a few minutes without any on hold music and found the non existent noise floor very annoying. I couldn't tell if the call had been dropped or not so I had to keep looking at the screen to see. On landlines there is usually enough of a noise floor to tell you are still connected and calls don't drop either. Granted it doesn't happen at much with cell phones anymore.

 

[satech]

On landlines there is usually enough of a noise floor to tell you are still connected and calls don't drop either.

That is actually "comfort noise" which is purposely injected by the telephone company to let the caller know the line is active. With today's fiber optics, landline phones could have no audible background noise, but callers became accustomed to that faint background noise during calls, so now it is artificially created.

 

[rbrucecarter5]

If anyone actually thinks that aircheck of WBZ-HD sounds good, he needs his head aligned. It sounds like a cheesy, chorusing, ringing low-fi web stream. I vastly prefer the analog - even strangled back to 4.7 kHz (if the analog were opened up to the permissible TWICE as wide bandpass I would like it even better.)

At least the voices sound human in analog. As opposed to the HD digital "Mr. Roboto in a sewer pipe" effect. It's a poor tradeoff for an intermittently-disappearing low noise floor.

And you honestly think any normal civilian listener would put up with the mode-hopping? I don't. And I've been doing this for 45 years. I know what people will put up with, and what they won't, and believe me - this represents the latter.

You think voice is annoying - try listening to music on AM HD radio. Now that is a horror story - the digital sampling is done at too low of a frequency - frequency translating and shifting high frequencies. The first few times it is interesting, but it gets annoying very fast. Contrast that with the robust C-Quam AM stereo that sounded so good on AM music stations. I remember hearing WLS Chicago in perfect stereo every night in Houston. That has to be lose to 1000 miles ---

 

[dumber than a box of hair]

Couple of other HD/analog comparisons in the WBZ aircheck. Far superior signal/noise ratio in HD. Night and day difference between the spacious dynamic range of HD vs the compressed, flat audio of the analog. Continuous audio levels in HD vs the rise and fall of analog audio with signal strength variations. No limit on frequency response, up to the designed parameters, of HD. Analog OTOH, needs to equalize or otherwise process it's audio in an attempt to compensate for poor receiver IF response, transmitter and antenna system deficiencies, uses heavy compression to provide maximum S/N ratios - yet for all that, background noise increase is still a function of distance from the xmtr.

Oh yeah... Seems like nobody noticed the perfect, seamless segue from HD back to analog when the signal deteriorated. Also the fact that the aircheck was stopped just as soon as the analog audio went over the cliff into static...

One could get the impression that digital technology has improved just about everything except radio...

-

If you think the HD portion of this aircheck sounds good, your ears need to go in the shop. Even my 61-year-old tinnitus-afflicted ears can hear how downright awful the HD sounds and how little dynamic range the digital audio has. The high end is squashed and tinny with a phasing effect which makes it uncomfortable to listen to.

 

[Savage]

Oh, rbruce, I have heard HD-AM playing music. I listened to the Disney outlet in Philly. With 50kw on 640 kHz this should have been a brick-wall signal, but no matter where I went in the northern 'burbs it sounded like it was coming in on a skywave from Whatchacallistan, and that was DAY pattern. The HD was a wall of noise, effectively. The station was playing a familiar Miley Cyrus song and I had to listen for a full fifteen seconds to decipher what it was. The analog channel was squashed too and typically narrowband as in AM-HD, but it at least sounded more like music. Kinda.

And people wonder why none of the Disney AMs moved the needle. At least, many do. But I don't.

 

[rbrucecarter5]

Oh, rbruce, I have heard HD-AM playing music. I listened to the Disney outlet in Philly. With 50kw on 640 kHz this should have been a brick-wall signal, but no matter where I went in the northern 'burbs it sounded like it was coming in on a skywave from Whatchacallistan, and that was DAY pattern. The HD was a wall of noise, effectively. The station was playing a familiar Miley Cyrus song and I had to listen for a full fifteen seconds to decipher what it was. The analog channel was squashed too and typically narrowband as in AM-HD, but it at least sounded more like music. Kinda.

And people wonder why none of the Disney AMs moved the needle. At least, many do. But I don't.,

Ah - Miley. She sure changed from the little girl we met when my daughter was on the show. The ones who didn't change - stayed themselves and very nice - Selena Gomez, Debby Ryan, Victoria Justice, Miranda Cosgrove, Ariana Grande, Liz Gillies - I don't know what happened with Miley, but I am worried about her. Yeah, and some of the ones we know are crossing over from Radio Disney to mainstream, others will shortly. Tremendous talents, and they do good shows.

One of the songs that got mangled was Jesse McCartney, he had a "ding" effect that got shifted down at least 5 kHz in frequency on HD - bizarre sounding. It makes me think the Nyquist sampling rate is way too low. Frequency undersampling will cause strange frequency shifts like that. As I recall, it needs to be at at least 2.2 times the frequency of the waveform sampled. Even then, that would only recover the fundamental - no overtones. So if you want to sample up to 20 kHz, the sampling frequency needs to be at least 44 kHz. Oversampling doesn't necessarily improve anything, it was merely done because faster data converters were available, and a filter to pass 20 kHz while rejection 44 kHz is ridiculously complex, but one to reject higher sampling rates is very simple. Oversampling = cheaper filter. Nothing else, besides a good marketing ploy.

Now - thinking again about AM HD - I don't see how they could squeeze 44 kHz of samples into the HD AM channels. For that matter, I don't see how they could sample even 10 kHz. So the Nyquist limit is breached, frequency translation happens, and it is horrendous to listen to.

I often wonder about Radio Disney's business plan going with HD AM. Little kids are on hand me down radios, and no parent will buy an HD radio for a little kid. But Audiocubes used to sell a $25 AM stereo C-Quam radio, and that is exactly what I suggested to the head of the radio network when they were in Dallas - use AM stereo C-Quam boards that cost next to nothing, put them in a cute plastic case with Mickey ear speakers - one for each channel, and sell them for $25 at Walmart. She obviously didn't listen.