• Get involved.
    We want your input!
    Apply for Membership and join the conversations about everything related to broadcasting.

    After we receive your registration, a moderator will review it. After your registration is approved, you will be permitted to post.
    If you use a disposable or false email address, your registration will be rejected.

    After your membership is approved, please take a minute to tell us a little bit about yourself.
    https://www.radiodiscussions.com/forums/introduce-yourself.1088/

    Thanks in advance and have fun!
    RadioDiscussions Administrators

KCBS 740 AM HD off again

D

danak6jq

I've been experimenting with a software-defined receiver (Softrock Ensemble II + HDSDR) for AM BCB DX, and I'm located about 25 miles east of the KCBS 740KHz AM/HD transmitter site. At 770KHz there is KCBC-AM, also AM/HD and about 85 miles from me. The two stations next to each other make a distinctive display of IBOC sidebands in the spectral 'waterfall' display and I noticed that KCBS's IBOC sidebands didn't look healthy; the upper primary IBOC was nowhere near flat, but KCBC's IBOC sidebands look like they're out of a textbook. I also noticed my Sony HD receiver wasn't reliably decoding KCBS' IBOC. So I did what a good listener does and I emailed KCBS AM via their website last Friday.

I noticed yesterday evening that KCBS has the IBOC off, it's still that way now. Enjoy.

Dana K6JQ
 
You're probably the only listener to email them that their HD is off. Nobody at the station cares more about its HD status than you do, not even the engineer.
 
Quoting from the email I sent KCBS:

Then again, I'm one of the 17 people in the Bay Area that even knows what IBOC is.
 
dumber than a box of hair said:
danak6jq said:
Quoting from the email I sent KCBS:

Then again, I'm one of the 17 people in the Bay Area that even knows what IBOC is.
Click to expand...

There are that many?
Click to expand...

Good question. The metropolitan Bay Area population is around 7.2 million people and I guessed 0.000236% of the people have heard of AM IBOC. That's including people that work at the radio stations. It could be optimistic, you're right.
 
It's funny...

Makes you wonder just how much bull it takes to prop up a system like HD radio, especially on the AM broadcast band. Most of us have been pulling up the legs of our pants for quite some time.
 
kc4rae said:
It's funny...

Makes you wonder just how much bull it takes to prop up a system like HD radio, especially on the AM broadcast band. Most of us have been pulling up the legs of our pants for quite some time.
Click to expand...

Talk about bull, read any of the way overly optimistic junk written in the radio mags lately?
 
When it comes to HD, yes. Badly optimistic. We know, but do broadcasters know?
 
We independent broadcasters definitely know. The scam is being perpetuated by iBiquity, the NAB, the big groups (mainly CBS, Clear Channel, Cumulus, NPR affiliates), and a few of the trade magazines -- most notably Radio World. Please don't lump us in with that group!
 
local oscillator said:
We independent broadcasters definitely know.
Click to expand...

Of course!

The question was meant to make a statement.  Why are these points being made about HD radio and it's benefits (many call question the validity of a hybrid transmission that doesn't work too well) repeated over and over again.  Do they think they'll change minds?  Nope and so far HD radio has only serve to change minds from users of HD to non-users.
The scam is being perpetuated by iBiquity, the NAB, the big groups (mainly CBS, Clear Channel, Cumulus, NPR affiliates), and a few of the trade magazines -- most notably Radio World.
Click to expand...
Scam?  Oh yeah.  At least from what I've read about it.
Please don't lump us in with that group! 
Click to expand...
Only if corporate radio was as good as smaller broadcasters.  I don't listen to any of the big ones anymore.

We do have an NPR station on MW that turned their HD off, which was a little of a surprise.  It has been off for about a month.
Sorry for further hijacking the thread.
 
Desperation never sleeps. HD-AM doesn't work, it can't work and never will. Even if it were stable and reliable - which it is not - I don't even think it sounds better than analog AM. Every example I've heard sounds screechy and artificial, consequences of the highly faked upper register which is generated in the ill-conceived CODEC. The only impressive effect is the lower noise floor. But your approval rapidly fades the longer you listen and ear fatigue starts to set in, with the uncomfortable fake-sounding audio rapidly causing an urge to turn it off and get back to hearing "real" broadcasts. And the irony: it sounds worst on spoken-word programming, precisely the primary content on AM radio today.

I know that AM is narrowband and relatively noisy. But when properly processed and heard through a decent receiver, AM can sound amazingly good. The main problem with the AM system today is on the receiving end, not the transmitting one. A standardized well-designed DSP receiver and abandonment of the 1990 NRSC preemphasis could work wonders with AM.
 
I had someone fooled into thinking that my old Pioneer SX-636 receiver was tuned to an FM signal when it was tuned to an AM non-HD station. The only thing I did was increase the treble to maximum gain and ensure that noise-generating lights and other devices were turned off. I thought we could live without the soda machine for a little while. :) You might wonder why I would listen to AM and deal with the problems with eliminating noise rather than FM? Because that's where the content I want is at. Most locally-owned stations in my area are on AM and play more music than the big FMs do.

It used to be that tuning an AM station was great with no noise interfering with reception. Now, it is a struggle. I'm flipping off lights and circuit breakers to find the source. It is worth the trouble, though, because I usually find problems to fix when I find something that causes interference.

When SBR was beginning to find codecs to attach to, my first thought was, "I don't know about this. It doesn't sound that much better." This was during the days of mp3PRO. At low bitrates, it does help but the encoding process was important for best results. It does have its limits. AACplus is great from 48 to 64kbps. Outside of that, it is either grungy or so smashed, it would be better without SBR. I think the bitrate of the codec HD uses for AM is much too low for SBR to be helpful.

Where I live at, AM has less noise interfering with reception than FM does.
 
Status
This thread has been closed due to inactivity. You can create a new thread to discuss this topic.


Back
Top Bottom