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RW: All-Digital AM Test On The Way

D

dumber than a box of hair

The October 10th edition of Radio World has an article about an upcoming test of an all-digital AM station (analog transmitter turned off), courtesy of the NAB Radio Technology Committee. Apparently a CBS-owned station (as yet unnamed) in a medium market will be the sacrificial lamb.

http://www.radioworld.com/article/station-chosen-for-all-digital-am-test-/215874

The Committee has been throwing around ways to "revitalize" AM and this is one option they want to try.
 
Wow Digital AM,

How does Ibiquity expect small market/mom and pop stations that don't even have the resources to even pay the power bill on their transmitters to pony up, 100+ thousands of dollars to modify system? Oh yeah...thats what CBS and Clear Channel want, get rid of the dead wood so their companies can grow,

sorta like some dictator from WW2 saying "we need room"
 
Radio World limits comments to 400 characters. Nevertheless I think I made my point about how AM HD is extremely prone to losing lock under interference scenarios. The modern home, office building, and highway are among the noisiest RF environments created by man - and also the environments where HD AM is supposed to work and be an improvement. I will dutifully listen to see if I can get HD lock, but I seriously doubt it will happen. The ONLY hope I have for all digital mode is the HD sideband pairs I heard 1000 miles from Chicago stations in the daytime. Had that been an HD radio, I am almost convinced I would have gotten HD lock. But that was in an area with no RF noise sources. I suppose I could drive out there with a couple of common RF noise sources and see if (1) I get 1000 mile HD lock and (2) how robust the lock would be. I could repeat that with their all digital test station. Personally, I think pursuing a wild aquatic fowl would be a better use of my time.
 
I would be curious to see how they do, but I just don't see the mediumwave band supporting anything digital. The problems mediumwave has for anything digital even when we assume its on a clear channel are the high noise floor from modern electronics noise, lightning discharge noise, and skywave. Assuming most AM listening is done via groundwave, skywave issues would be distant stations adding interference at night, especially lower powered stations that aren't on clear channels.

HD Radio has a problem with all of these and the problem is worse due to the fact that the signal sits on the adjacent sidebands, meaning that 2 strong clear channel stations effectively jam each other such as KDKA and WBZ.

I still think opening up VHF channels 5 and 6 for radio would be better. It would be cheap to add these frequencies to new radios, and there are already many chip based radios out there that tune the Japanese FM band and only have it disabled via software.
 
spunker88 said:
I still think opening up VHF channels 5 and 6 for radio would be better. It would be cheap to add these frequencies to new radios, and there are already many chip based radios out there that tune the Japanese FM band and only have it disabled via software.
Click to expand...

All of you can forget Channels 5 & 6 for FM. The FCC is determined to put as many televisions stations as it can back onto VHF during the repacking process. Speculation among LPTV station owners is that VHF will be the primary home of low power TV. The commission has already increased the power for LPTV on VHF from 300 watts max. to 3 kW ERP and a few stations are running 5 kW ERP on an STA basis. As it is, there are still a few full power stations on 5 and 6. I doubt they will be allowed to move higher on the band during repacking.

So you'll have to make the AM band work the best you can--or convince the FCC to open up the shortwave bands for domestic use (and DRM-only). But forget channels 5-6; it's a dead issue.
 
Carmine5 said:
... and a few stations are running 5 kW ERP on an STA basis.
Click to expand...

Can you point me to a reference for that?

(I don't doubt it in the least! -- would just like to know the details)
 
dumber than a box of hair said:
The October 10th edition of Radio World has an article about an upcoming test of an all-digital AM station (analog transmitter turned off), courtesy of the NAB Radio Technology Committee. Apparently a CBS-owned station (as yet unnamed) in a medium market will be the sacrificial lamb.
Click to expand...

Hmmm. There are a limited number of markets where CBS has more than one AM station or an AM small enough they might be willing to sacrifice it. I would suggest the most likely possibilities are:

KIKK, Houston (low-powered daytimer)
WNEW, Washington (top of the dial & low power at night)
KYDZ, Las Vegas (currently children's radio, doesn't seem like a very desirable format in Vegas!)
WAOK, Atlanta (limited night coverage)
WBCN, Charlotte (ditto)

It may (or may not) be necessary to scratch KIKK, WNEW and WAOK from the list due to the "medium market" comment. If forced to bet money, I'd put it on KYDZ.
 
When they perform the experiment is the plan to up the digital power to the equivalent analog power, or keep the existing flea power HD signal with just the analog turned off?

Be interesting to see what the results of a test for the first option would be.
 
dumber than a box of hair said:
The October 10th edition of Radio World has an article about an upcoming test of an all-digital AM station (analog transmitter turned off), courtesy of the NAB Radio Technology Committee. Apparently a CBS-owned station (as yet unnamed) in a medium market will be the sacrificial lamb.
Click to expand...
I wonder if the FCC would allow CBS to switch KFWB 980 to all digital to simulcast KNX 1070. They are 5kW and, from what I read, may improve the ratings to a few dozen listeners. :D

But seriously, a Mt. Wilson signal is one of the best ways to (dis)prove the merits of all-digital AM-HD.
 
Or maybe we can just make our observations AFTER we've actually seen how a pure HD MW signal performs in real world conditions...
 
ajc_trw said:
But seriously, a Mt. Wilson signal is one of the best ways to (dis)prove the merits of all-digital AM-HD.
Click to expand...

Actually mediumwave (AM) does not require height to broadcast its waves; it requires ground conductivity. VHF (FM) and above do require HAAT.
 
The limitation is the much lower resolution at 1 mhz vs 100 mhz.
It is FAR easier to define "sharp corners" on data using a sine wave carrier reference at 100 Mhz.

At 1 Mhz, in addition to the previously mentioned manmade noise and natural noise, there's a lot
of bits referenced against a carrier sinewave at or near zero-crossing, and these disappear as far as the
receiver is concerned.

It's like asking ocean liners to do ballet.
 
Why all the secrecy about which station? Tell us so we can set up the monitoring stations properly. Or - do they plan on just sneaking in a 15 minute test with no independent monitoring, declare it a rousing success, pat themselves on their back that they were right all along, AM HD is fixed, all that is required is people to buy 500 million new radios and all will be right with the world. Whew! Solved that problem ----
 
rbrucecarter5 said:
do they plan on just sneaking in a 15 minute test with no independent monitoring, declare it a rousing success, pat themselves on their back that they were right all along, AM HD is fixed...
Click to expand...

...as if they haven't done that already. (The FM tests in Boston a few years back, where iBiquity and Greater Media deliberately kept third parties away from the testing.)
 
Rumor that I heard was, it's a CBS station in North Carolina, and it's changing formats. So, this will be a 2-3 week HD Radio version of "stunting".
 
kenglish said:
Rumor that I heard was, it's a CBS station in North Carolina, and it's changing formats. So, this will be a 2-3 week HD Radio version of "stunting".
Click to expand...

That would be either WBCN-1660 or WFNZ-610, both in Charlotte.
 
Somebody mentioned equipment cost but neglected to mention the extortion required royalty payments to iBiquity! Small market radio would be smart to not even get in bed with these guys, especially when I hear some of the bigger stations shutting this garbage off.

I think HD radio really means Hype Dependent radio.
 
w9wi said:
kenglish said:
Rumor that I heard was, it's a CBS station in North Carolina, and it's changing formats. So, this will be a 2-3 week HD Radio version of "stunting".
Click to expand...

That would be either WBCN-1660 or WFNZ-610, both in Charlotte.
Click to expand...
IF this is true, my bet would by far be on WBCN. CBS isn't going to get rid of any sports stations anytime soon with their new network up, and something tells me those call signs really don't belong there.

And don't be surprised if the new format is another sports station. No joke...

Radio-X
 
CBS still uses WBCN for web sites in Boston. WBCN was a legendary rock station and CBS wanted to park the call letters.
 
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