Experimental high power IBOC operation

[Radioman100]

I recently learned that at least one station in a top 10 market has an experimental permit to operate FM IBOC at 10X the normal power level and has been operating it at that power level for quite some time.

It's a top 10 performing station in terms of 12+ numbers and is a very good performer in its target demographics. Its ratings have improved while this experimental operation has been taking place.

People I know who have had the opportunity to listen to it in HD say its HD signal is comparable in every way to the station's analog signal. In many ways, it performs better.

I'm curious to see if anyone can guess which station it is. I'm also curious to know if there are any others like it.

 

[4dude]

w0w 10x??

10X the interference!!!!!!!!!!!!


UNREAL

 

[fmradionuts]

I'll take a stab at it...KIIS 102.7???? ;D

 

[K-Tel]

I wonder if it's the same HD station that will be fully staffed??? There was an Inside Radio and Radio Records report on this a few weeks ago.

 

[davideduardo]

I recently learned that at least one station in a top 10 market has an experimental permit to operate FM IBOC at 10X the normal power level and has been operating it at that power level for quite some time.

It's a top 10 performing station in terms of 12+ numbers and is a very good performer in its target demographics. Its ratings have improved while this experimental operation has been taking place.

People I know who have had the opportunity to listen to it in HD say its HD signal is comparable in every way to the station's analog signal. In many ways, it performs better.

I'm curious to see if anyone can guess which station it is. I'm also curious to know if there are any others like it.

Two stations in Americas top revenue market increased the HD signal by 10 db for an experimental period. Not 10 x... 10 db. The feeling is that an increase on the order of 5 to 6 db might work as a broad based FM enhancement, but not 10 db. The stations involved, and those next adjacent channel with them signed confidentiality agreements. I am surprised you are suggesting revealing the nature of the test.

 

[davideduardo]

I'll take a stab at it...KIIS 102.7???? ;D

Way too low power for a conclusive test.

 

[Radioman100]

Two stations in Americas top revenue market increased the HD signal by 10 db for an experimental period. Not 10 x... 10 db. The feeling is that an increase on the order of 5 to 6 db might work as a broad based FM enhancement, but not 10 db. The stations involved, and those next adjacent channel with them signed confidentiality agreements. I am surprised you are suggesting revealing the nature of the test.

David, I think you just revealed a lot more than I did. I heard about this 3rd hand, thus my incorrect information about it being 10X HD power, not 10 dB.

Since you know about confidentiality agreements (I didn't BTW) is it safe to assume the other one is a Univision station?

 

[Radioman100]

w0w 10x??

10X the interference!!!!!!!!!!!!


UNREAL

Apparently not. This has been on for a while and nobody has complained at all.

 

[davideduardo]

Two stations in Americas top revenue market increased the HD signal by 10 db for an experimental period. Not 10 x... 10 db. The feeling is that an increase on the order of 5 to 6 db might work as a broad based FM enhancement, but not 10 db. The stations involved, and those next adjacent channel with them signed confidentiality agreements. I am surprised you are suggesting revealing the nature of the test.

David, I think you just revealed a lot more than I did. I heard about this 3rd hand, thus my incorrect information about it being 10X HD power, not 10 dB.

Since you know about confidentiality agreements (I didn't BTW) is it safe to assume the other one is a Univision station?

Nope. And the test was for a relatively short period of time; all stations are back to normal. For all I know, they did similar tests in some other markets. I'm not under any agreement...

 

[Radioman100]

Nope. And the test was for a relatively short period of time; all stations are back to normal. For all I know, they did similar tests in some other markets. I'm not under any agreement...

The experimental permit for the station I'm referring to doesn't expire for several months. I heard the test is still going on, but I also heard it was at 10X power, so my info may be faulty.

 

[davideduardo]

Nope. And the test was for a relatively short period of time; all stations are back to normal. For all I know, they did similar tests in some other markets. I'm not under any agreement...

The experimental permit for the station I'm referring to doesn't expire for several months. I heard the test is still going on, but I also heard it was at 10X power, so my info may be faulty.

Or it is a different test.

 

[Radioman100]

Or it is a different test.

Maybe so. One thing's for sure though, IBOC testing is ongoing and the current HD power levels may be increased as a result.

The lack of complaints in these major markets leads me to believe the tests have been successful.

 

[JohnnyElectron]

Are any of the 50KW AM clear channel frequency stations trying a stronger AM HD signal? The first night of HD I couldn't get any except my 2 locals; tonight I've been able to DX 3 or 4 clear channel stations and get it to lock into HD long enough to get their call letters and ID!

 

[w9wi]

Are any of the 50KW AM clear channel frequency stations trying a stronger AM HD signal? The first night of HD I couldn't get any except my 2 locals; tonight I've been able to DX 3 or 4 clear channel stations and get it to lock into HD long enough to get their call letters and ID!

Propagation was pretty bad on the first night of nighttime HD, things were a lot better the last two days.

Also, I suspect a number of stations didn't bother running the HD at night on the first night, since it wouldn't have been legal between sunset & midnight & someone would have had to come in & manually turn on the HD at midnight.

I got both PAD ("text ID") and digital audio from KMOX-1120 (St. Louis, ~240mi.) and WTAM-1100 (Cleveland; 400mi?) last night. WTAM delivered about 30 seconds worth, although it would occasionally blend back to analog. Their analog wasn't in delay, so it was kinda like deja-vu when it popped back into digital & I heard what they said on analog 8 seconds ago!

Stations that were blinking the HD light (but delivered neither digital audio nor PAD) last night:
WLW-700 WGN-720 WJR-760 WBBM-780 WHAS-840 WHO-1040 WTAM-1100
KMOX-1120 WOWO-1190 WOAI-1200 WPHT-1210 WRDZ-1260 (R. Disney/St. Louis)
WLAC-1510 (night pattern doesn't favor my direction, analog signal is lousy too)
WRLL-1690

and an unID on 990. On analog I was hearing what I'm pretty sure was Winnipeg, but I'm also almost certain no Canadian AM stations are currently running HD.

Using a Boston Acoustics and a 260-foot ham antenna.

==========================================

At the risk of making a seriously embarrassing mistake... aren't 10dB and 10x the power the same thing?

(10 *voltage* dB are not the same as 10x, but 10 *power* dB are - 10log(P2/P1) )

==========================================

The ability to run significantly higher digital power certainly would seem to make HD work a LOT better. I would imagine it could be done on FM in a few markets where there aren't any first-adjacents for a LONG ways. Vegas, Boise, Salt Lake, places like that. It's hard to imagine being able to do it in NYC or Chicago.

(do NOT tell my fellow DXers I said that!)

 

[Play Freebird]

I recently learned that at least one station in a top 10 market has an experimental permit to operate FM IBOC at 10X the normal power level and has been operating it at that power level for quite some time.

I'm curious to see if anyone can guess which station it is. I'm also curious to know if there are any others like it.

Not sure if this is by intent, but WYSP's digital sidebands currently appear about 10 dB higher than those of most other Philadelphia stations. I believe 'YSP is now using the ERI master antenna at American Tower's recently-built "candelabra" DTV facility, which has a combiner that can be fed a separate digital input. This configuration would make it relatively simple to increase the digital to analog ratio for test purposes.

Another CBS station sharing that site is WOGL, but they're using "space combining" with the analog transmitter feeding the master panel antenna and the digital going into a side-mounted aux antenna mounted lower on the southeast leg of the tower. I'm on the opposite side of the tower and measure nearly a 10 dB deficiency in digital to analog ratio on both sides. Yet, WOGL seems to decode nearly as well in this area as the other local stations.

If these tests lead to a push for higher digital "injection levels", digital coverage will undoubtedly improve, but this will not be a cure-all for HD-2 dropouts in markets with challenging terrain, nor would this mode of operation comply with the FCC mask. Like anything else, it's a tradeoff and some stations will notice objectionable interference in areas where it didn't previously exist. A new rulemaking would be required, so I expect a lot of opposition from stations that would receive greater interference.

 

[Mike Walker]

Well everything in life's a tradeoff. Sadly, when the FCC mandated In Band On Channel, with simultaneous analog and digital modes in operation, they pretty much guaranteed that difficult, and sometimes painful tradeoffs were coming! Here they are!

I've still not experienced ANY audible interference from FM HD (and I've tried!) But a recent swing close to Charlotte NC led me to believe that the sidebands are "buzzing" at some of the AM HD stations there!

 

[Len14043]

In a nutshell for FM, the tradeoff is IBOC for the ability to listen to first ajacient channels. FM IBOC is innoucuous except to the most diehard DXers (I am not denigrading DXers in any way seeing that I am one).

 

[4dude]

I love DXing but i think IBOC is more damaging from .53 to 1.7Mhz

 

[Mike Walker]

I still don't buy that FM IBOC does much damage to 1st adjacents. I am between WFDD, 88.5 in Winston Salem (non-HD), and WNCW 88.7 in Spindale NC (HD). I can easily get WNCW IN HD, with no interference from WFDD, and vice versa. Then I have a new antenna, rotor, and pre-amp...but a "serious dxer" would likely have proper gear as well!

 

[Len14043]

Mike,
I should have clarified what I meant by first ajacients. I was referring to listening to an out-of-market station ajacient to a local station. We have a local on 102.7 in Cincinnati. Prior to 102.7 running IBOC, a station on 102.9, about 70 miles distant, was receivable with a good radio, albiet with considerable splatter from 102.7. After 102.7 implemented IBOC, noise is heard on 102.9 resembling a blank channel, but is actually the digital signal. The first ajacient is covered by the capture effect of the digital sideband. The interference is minimal and acceptable to most people, but nevertheless still present. Correct me if I am wrong, but I believe you were referring to 2 semi-locals on ajacient frequencies. For AM, the interference in much more pronounced.