That's just lazy engineers not doing their jobs!
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HD on WINS and WCBS AM
- Thread starter mets18
- Start date
That's just lazy engineers not doing their jobs!
While traveling through Washington DC, I made sure to tune into the HD only AM station they are experimenting with right now. WWFD AM 820
https://wtop.com/frederick-county/2...first-all-digital-am-radio-station-in-the-us/
It sounded very good. The one very odd thing was that you had to know it was there. Unlike any other station, when you tuned in, since there was no analog signal, it took a couple of seconds for it to come on. Only a couple, but enough that someone could easily just tune past.
Did the station stop your radio from scanning?
The HD/analog sync drifts over time. You can set it up to be perfect and then a week later it'll be slightly out of sync again. Many major-market stations now use special processing that automatically measures the HD/analog delay and adjusts it to always keep it in sync.
Most Atlanta stations run a device built by Innovonics which automatically keeps the analog and HD1 in time sync. It is the Justin 808 and does a fantastic job...my FM is never further than a frame or two off.
So don't blame the "lazy"engineers!!!
My own experience listening to AM-HD is I thought it was somewhat an improvement in sound quality depending on the station - certainly a lower noise floor with HD. Also when Radio Disney still had a bunch of HD AM's running, I found music better than news/talk on HD. Any digital artifacts were not as noticeable to my ears. Station's with good analog coverage seem to do best with it (like KMOX mentioned earlier, WTIC, WPHT, WBZ when they ran it). With WINS and WCBS around NYC it did seem to cut in an out of HD a lot falling back to analog in my limited experience driving around Manhattan. It seems to work better once you get out of the city a bit for some reason (maybe HD is more affected by the tall buildings?)
My experience with the FM-HD 2 and 3 signals is not great. Cuts out too much and when it does it doesn't fall back to analog - just no sound - so I'd rather stay on AM. If HD radio supported failback from and FM-HD 2 or 3 to an analog AM that would be an interesting but it doesn't.
During the CBS radio days, when they went to the 8khz analog mode with their HD-AM's that made a big improvement in the analog quality on my radios (mostly units with wider bandwidth). Many AM's were running to AMAX standards (10khz) in mono or stereo right up to when AM-HD became common but then some fell under corporate mandates (as I understand) to conform to the HD frequency cutoffs even if not running HD. At one point I think Clear Channel/iHeart mandated 5khz cutoff on all stations but seems that is more relaxed now. Also my experience was the CBS stations moving to 8khz mode eliminated the self inflicted digital noise on their analog signal.
Generally if AM sounds bad on your radio it is your radio. My Ford vehicles have generally had decent AM sections. Units from the late 90's and early 2000's - especially those with AM stereo support - are good out to the AMAX specs and sound great. My last GM car - 2008 model year - the AM was pretty narrow and not that great sounding. At home I have a Denon wide bandwidth tuner that sounds great. My Yamaha tuner with HD capability is ok but not as good on AM analog. I have an aftermarket Pioneer HD capable radio in one vehicle that has a decent analog AM section - better than the GM unit. Adjusting the tone controls or equalizer if the radio has them can help.
If you want to hear great sounding AM - find a wide bandwidth, AM stereo tuner (like in the Ford vehicles from the late 90's) and listen to WJIB in Cambridge/Boston MA. Spectacular sound and pretty good coverage considering the transmitter power.
I was hopeful when HD came out it would help AM especially since with it being an update for both FM and AM, it would tend to just come with new radios more than the last attempt to help AM (AMAX and C-Quam) but between the low adoption, competition with streaming, end consumers not needing it for FM since FM sounds fine already and has a data stream with RDS it just hasn't taken off that well. Add in the expense of licensing for stations using it and extra maintenance of equipment for thin engineering crews the future does not seem that bright for it.
My experience with the FM-HD 2 and 3 signals is not great. Cuts out too much and when it does it doesn't fall back to analog - just no sound - so I'd rather stay on AM. If HD radio supported failback from and FM-HD 2 or 3 to an analog AM that would be an interesting but it doesn't.
During the CBS radio days, when they went to the 8khz analog mode with their HD-AM's that made a big improvement in the analog quality on my radios (mostly units with wider bandwidth). Many AM's were running to AMAX standards (10khz) in mono or stereo right up to when AM-HD became common but then some fell under corporate mandates (as I understand) to conform to the HD frequency cutoffs even if not running HD. At one point I think Clear Channel/iHeart mandated 5khz cutoff on all stations but seems that is more relaxed now. Also my experience was the CBS stations moving to 8khz mode eliminated the self inflicted digital noise on their analog signal.
Generally if AM sounds bad on your radio it is your radio. My Ford vehicles have generally had decent AM sections. Units from the late 90's and early 2000's - especially those with AM stereo support - are good out to the AMAX specs and sound great. My last GM car - 2008 model year - the AM was pretty narrow and not that great sounding. At home I have a Denon wide bandwidth tuner that sounds great. My Yamaha tuner with HD capability is ok but not as good on AM analog. I have an aftermarket Pioneer HD capable radio in one vehicle that has a decent analog AM section - better than the GM unit. Adjusting the tone controls or equalizer if the radio has them can help.
If you want to hear great sounding AM - find a wide bandwidth, AM stereo tuner (like in the Ford vehicles from the late 90's) and listen to WJIB in Cambridge/Boston MA. Spectacular sound and pretty good coverage considering the transmitter power.
I was hopeful when HD came out it would help AM especially since with it being an update for both FM and AM, it would tend to just come with new radios more than the last attempt to help AM (AMAX and C-Quam) but between the low adoption, competition with streaming, end consumers not needing it for FM since FM sounds fine already and has a data stream with RDS it just hasn't taken off that well. Add in the expense of licensing for stations using it and extra maintenance of equipment for thin engineering crews the future does not seem that bright for it.
This could be done easily by the receiver manufacturers just as they have done for decades in Europe and elsewhere;
one tunes in a station and the receiver finds it on other frequencies as they travel about.
Of course the AM, FM, DAB, or whatever stations would all need to transmit some identifying data.
One of the original intentions of the system was to synchronize European broadcasts as people drove across a country or even between two towns. It is sort of like diversity reception; it picks the best simulcast signal out of several/many that are available.
But the difference is that the European version is based on lots of simulcast national networks, covering whole regions or nations and some with hundreds of stations and repeaters. In the US, that was and still is very uncommon. So it's not part of the system here.
The HD standard for AM requires 5 kHz analog bandwidth. Some stations have managed to do 6 kHz and a few tried 7 kHz. I am not familiar with any 8 kHz operations.
There are so few remaining AM HD stations that all this is a sort of theoretical argument.
But there are quite a few simulcast regional networks. NPR affiliates with multiple transmitters come to mind. And then of course there's K-Love, which can often be heard on multiple signals in a market. Anyone know of a station group that's using that code to make receivers switch frequencies? I've done some searching but can't really find the mechanism by which this would work. It almost seems like a radio would have to have two separate tuners to see if an alternate station is really there.
Dave B.
At least when the last time I checked, KRCD and KRCV in LA, the double Class A FM simulcast, has the switching function activated. However, we were told that only certain European cars had that version of receiver technology so, for a Spanish language station, that's not much of an advantage.
Most newer receivers that are software controlled are able to scan the entire band, and simply pick the station you want out of everything that is available.
The RDS system that allows automatic finding and switching of frequencies for the best signal of a national or regional network have been in use in Europe for about two decades.
Think of it like the FM transmission antenna system on the Empire State Building. It can broadcast a whole bunch of stations from the top to the bottom of the FM band without any station to station interference.
A modern FM receiver chip can change channel in ~1 millisecond, so if the signal is weak enough to be noticeable to the listener it would be possible for the radio to check the alternate channel indicated in RDS / HD metadata without the listener thinking anything of it.
I have no idea if any actual radios sold in the US implement the behavior.
I have no idea if any actual radios sold in the US implement the behavior.
Modern DSP-based car radio tuners receive the entire AM or FM band simultaneously. For example the radio in my 2018 VW can give you a list of all the stations on the band, including HD/RDS text data, which displays instantaneously, not needing to scan sequentially through all the frequencies like older radios.
You know, I didn't try that. Damn. Next time.....
God no! Most engineers I've met are exactly the opposite. But in one market I was in, well, it was NOT like that.
When I last inquired, quite a few years ago, I found that European made cars and even the European brands assembled in the US had the search-and-seek function to find the best out of many signal of multi-station networks.
My European mark car made in Alabama was able to do this, an a later European car made in the Carolinas also did.
KNX 1070 in Los Angeles has also turned off their AM HD signal. Just noticed that this weekend. Is this a nationwide thing by Entercom due to the Coronavirus Pandemic or is the timing just a coincidence?
Could be something planned previously or could be that they don't want additional engineering issues caused by the system to affect them during this time.
Could even be that the encoder (many of the AM ones are near end of life) failed and now is not the right time to be driving out to the transmitter to fix it.
If off for an extended period of time, could be the hard drive in the exciter died. For the original AM IBOC systems, many are now considered out of support by the manufacturer.
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