When an AM station's IBOC interferes with a local station...

[Buckeyes2001]

1220 WHKW/Cleveland is a local station to me but at night, the IBOC from WPHT 1210/Philadelphia chews them up.

Do you have cases of local AM stations getting beat up by IBOC from another station?

 

[KR4BD]

It's not quite "local" to me, but WLW-700 often gets stepped on by WOR's I-BUZZ at night in Lexington, KY. Before WLW turned their off noise generator, their I-BUZZ stepped on WOR!

Now.... That's what I called "mutually assured signal destruction" (MASD) !

 

[schmave]

It's not quite "local" to me, but WLW-700 often gets stepped on by WOR's I-BUZZ at night in Lexington, KY. Before WLW turned their off noise generator, their I-BUZZ stepped on WOR!

Now.... That's what I called "mutually assured signal destruction" (MASD) !

WLW gets trashed by WOR's IBOC a good deal here in Thornville, Ohio, 30 miles east of Columbus. But go even 15 miles west and WLW is considerably stronger ... we're just at the start of the ring of cancellation.
There have been reports of KDKA being smashed by WBZ's IBOC within 40 miles of Pittsburgh at night. That's where it becomes even more unacceptable, to not get a local station within the market.

 

[KeithE4]

There have been reports of KDKA being smashed by WBZ's IBOC within 40 miles of Pittsburgh at night. That's where it becomes even more unacceptable, to not get a local station within the market.

How about a situation where a distant IBOC obliterates a station within its own city of license?

That's what happens when KNX 1070's IBOC wipes out Tempe (SE-suburban Phoenix) AZ's KDUS 1060 at a distance of ONE MILE south of its transmitter. To be fair, KDUS's 500 watt night signal is required to be almost totally nulled to the south to protect XEG 1050 Monterrey (its ERP is 5 watts at best directly south of its towers), and Tempe grew past the limits of the signal in the '70s.

Los Angeles is about 350 miles west of Tempe. There is no reason whatsoever for its IBOC signal to be heard here, especially when the normal AM signal is actually weaker at times. Even though KDUS can't upgrade its signal, and the city (actually, the whole Phoenix market, which has grown 10-fold since 1060 signed on in the '50s) has outgrown the station's reach, there is no excuse for something like this ever happening. I hear KNX hash overriding KDUS when driving down I-10 starting at about 3/4 mile south of the KDUS transmitter.

 

[Darth_vader]

"WOR's I-BUZZ"

Your radio's front-end must be extremely narrow if it makes the white noise of a mediumwave Ibiquity channel sound like "buzzing". I can't begin to imagine what speech and music must sound like on that rig. Yikes...

 

[BobOnTheJob]

The noise floor on WHAS 840 Louisville,KY starts rising 30 miles from their 50KW non-d site thanks to 830 WCCO's IBOC from Minnesota. By the time you're 50 miles from WHAS, it's not anything you'd want to listen to.

 

[rbrucecarter5]

The noise floor on WHAS 840 Louisville,KY starts rising 30 miles from their 50KW non-d site thanks to 830 WCCO's IBOC from Minnesota. By the time you're 50 miles from WHAS, it's not anything you'd want to listen to.

Oh THAT explains what happened to WCCO! They used to be an easy catch here in Texas, once you null WBAP. Not so any more, that HD AM is a power vampire or something. WCCO used to be such a powerhouse that I could get them DAYTIME in Lubbock, TX with a large loop antenna. Of course Lubbock has high ground conductivity so all the Chicagos, etc. also come in.

I wonder how WCCO penetrates buildings in the Twin Cities with that HD power vampire ----

 

[radioman148]

The noise floor on WHAS 840 Louisville,KY starts rising 30 miles from their 50KW non-d site thanks to 830 WCCO's IBOC from Minnesota. By the time you're 50 miles from WHAS, it's not anything you'd want to listen to.

Oh THAT explains what happened to WCCO! They used to be an easy catch here in Texas, once you null WBAP. Not so any more, that HD AM is a power vampire or something. WCCO used to be such a powerhouse that I could get them DAYTIME in Lubbock, TX with a large loop antenna. Of course Lubbock has high ground conductivity so all the Chicagos, etc. also come in.

I wonder how WCCO penetrates buildings in the Twin Cities with that HD power vampire ----

That daytime reception of WCCO & the Chicago stations in Lubbock would I assume only be in the winter?

 

[tomservo]

Nope. Only one local I can hear at night and that's because I'm practically under their stick. No IBOC interference here. Cuba is a much bigger problem.

 

[FreddyE1977]

WDZZ (formerly WTAE/WEAE), the local Radio Disney on 1250, throws out a band of buzz that literally
blankets everything from 1210 up to around 1290. Granted I live pretty close to the tower. But coming
dangerously close to WJAS on 1320.

They seem to be the only local AM that runs this thing anymore (to serve all those tweens out there
with HD radios, no doubt)

 

[Buckeyes2001]

Also here in Vermilion, OH the noise floor on 1380 WDLW/Lorain starts rising before you get to the Erie County line from WSPD 1370/Toledo during the day from their IBOC.

 

[gar hi]

I've never once heard IBOC hiss from any station outside our local radio market.

Am I the only one?

The loudest station at night here is WWL but I've never heard IBOC noise from them.

Do they turn it off at night?

Our big stations WDAE, WFLA, and WHNZ don't have IBOC hiss at night.

 

[BobOnTheJob]

I've never once heard IBOC hiss from any station outside our local radio market.

Am I the only one?

The loudest station at night here is WWL but I've never heard IBOC noise from them.

Do they turn it off at night?

Our big stations WDAE, WFLA, and WHNZ don't have IBOC hiss at night.

Wow gar...count yourself blessed. Do you hear WWL IBOC hiss during the day? I don't know if they run IBOC or not, but if you take that portable to the beach, I'd think that 860 or 880 would have at least some audible hiss during the day if they are.

 

[gar hi]

As strong as WWL is at the beach in the daytime, I've never heard any IBOC hiss.

 

[rbrucecarter5]

That daytime reception of WCCO & the Chicago stations in Lubbock would I assume only be in the winter?

Nope, I purposely tried at different times of the year. Pretty consistent. It took a loop at least three feet on a side, better results with 4 and 5 foot loops. I also had things like the Chicagos, even WBBM strong enough to overcome interference from a local 790. Other things like WSM, WSB. The ground conductivity is extraordinary there. Daytime reception at those distances is characterized by deep fades sometimes lasting minutes or even an hour or two. But they always fade back in. Surprisingly little from the West, you would think KFI would have been a shoe-in. But no - all WWLS from OKC.

 

[pianoplayer88key]

That daytime reception of WCCO & the Chicago stations in Lubbock would I assume only be in the winter?

Nope, I purposely tried at different times of the year. Pretty consistent. It took a loop at least three feet on a side, better results with 4 and 5 foot loops. I also had things like the Chicagos, even WBBM strong enough to overcome interference from a local 790. Other things like WSM, WSB. The ground conductivity is extraordinary there. Daytime reception at those distances is characterized by deep fades sometimes lasting minutes or even an hour or two. But they always fade back in. Surprisingly little from the West, you would think KFI would have been a shoe-in. But no - all WWLS from OKC.

Fades? Sounds like some residual skywave to me. Maybe there's a limit to the daytime ionispheric absorption even in summer and your antennas are sensitive enough to overcome it somewhat? If not, what do you think could be causing the fading?
With your larger loops, do you think it's possible to have two co-channel class A daytime signals mixing like XEKT & KLTX at Pacific Beach NW of Sea World on the SRF-59 (assuming there were no other interfering signals) if you're at the right location? I'm thinking something like XEWA vs CBK, KFAR vs WFAN, WOR vs KIRO, WSB vs KFQD, WBBM vs KNOM, CKLW(?) vs XEROK, KGO vs WGY, XEPRS vs WBAL (ignore KAAY), CKWX vs WBBR, KFBK vs WSAI, KNZR vs WQEW?
Also any idea how your loops would compare to the ferrite sleeve loop antennas discussed on the ultralightdx group, as well as Gary Debock's PVC frame air core loops? Also have you had a chance to try any of the DSP Si4734-based radios? I have a PL-398mp that I like fairly well, along with a couple others.

 

[radioman148]

That daytime reception of WCCO & the Chicago stations in Lubbock would I assume only be in the winter?

Nope, I purposely tried at different times of the year. Pretty consistent. It took a loop at least three feet on a side, better results with 4 and 5 foot loops. I also had things like the Chicagos, even WBBM strong enough to overcome interference from a local 790. Other things like WSM, WSB. The ground conductivity is extraordinary there. Daytime reception at those distances is characterized by deep fades sometimes lasting minutes or even an hour or two. But they always fade back in. Surprisingly little from the West, you would think KFI would have been a shoe-in. But no - all WWLS from OKC.

This is interesting that you would get fades during the day. Definitely indicates skywave properties. What time of the day have you usually heard this?

 

[stacker]

I have noticed increased interference to local stations from co-channel stations running IBOC. Happens during critical hours, before sunset and right after sunrise. The digital component being broadcast seems to increase the effect of the normal fading that would occur with two analog signals beating against each other. I've observed this inside the city grade contours of some stations.

 

[Bongwater]

Let's just say it's probably not going to get better.......

http://www.radiosurvivor.com/2012/10/04/nab-debating-the-future-life-or-death-of-am-radio/

 

[rbrucecarter5]

That daytime reception of WCCO & the Chicago stations in Lubbock would I assume only be in the winter?

Nope, I purposely tried at different times of the year. Pretty consistent. It took a loop at least three feet on a side, better results with 4 and 5 foot loops. I also had things like the Chicagos, even WBBM strong enough to overcome interference from a local 790. Other things like WSM, WSB. The ground conductivity is extraordinary there. Daytime reception at those distances is characterized by deep fades sometimes lasting minutes or even an hour or two. But they always fade back in. Surprisingly little from the West, you would think KFI would have been a shoe-in. But no - all WWLS from OKC.

Fades? Sounds like some residual skywave to me. Maybe there's a limit to the daytime ionispheric absorption even in summer and your antennas are sensitive enough to overcome it somewhat? If not, what do you think could be causing the fading?
With your larger loops, do you think it's possible to have two co-channel class A daytime signals mixing like XEKT & KLTX at Pacific Beach NW of Sea World on the SRF-59 (assuming there were no other interfering signals) if you're at the right location? I'm thinking something like XEWA vs CBK, KFAR vs WFAN, WOR vs KIRO, WSB vs KFQD, WBBM vs KNOM, CKLW(?) vs XEROK, KGO vs WGY, XEPRS vs WBAL (ignore KAAY), CKWX vs WBBR, KFBK vs WSAI, KNZR vs WQEW?
Also any idea how your loops would compare to the ferrite sleeve loop antennas discussed on the ultralightdx group, as well as Gary Debock's PVC frame air core loops? Also have you had a chance to try any of the DSP Si4734-based radios? I have a PL-398mp that I like fairly well, along with a couple others.

Well, two people asked about the deep fades. Most of the time, I was listening from late morning to early afternoon. A couple of times later, a couple of times earlier. I went out there several times of the year, and had a lot of time on my hands to do DX'ing. I actually left my large loops in my father's storage shed between trips. I tried several radios, etc.
I am assuming a lot of skywave, possibly interfering with and cancelling ground wave. I'm not the only one to do 1000 mile plus daytime reception - I've seen several other DX'ers report it. Usually they are in an area of good ground conductivity -like near the beach. I have done it myself when I lived on a barrier island in Florida. New York stations were so reliable that I depended on them. No loop was even needed there.

None of my locations was anywhere close to equidistant from two 50 kW stations, so I can't attest to whether they swap or not in the daytim. I have never used a large loop at night, because anywhere in the US it would probably swamp with stations. Although it might be interesting to try for split channels. I know I got an interesting split channel in the 80's with a loop at night, but so many stations have come on the air since then that I doubt I would have much luck.

Another 1000 mile reception scenario was in a remote part of New Mexico, when the sideband pairs of Chicago stations were clearly audible, even when not a trace of the carrier or analog was. WCCO sidebands were there, too. Next time I drive through there, I'll take a camera and record a youtube or something. I've never had it not happen, I've taken to stopping at that remote rest stop just to marvel at how tenacious the sidebands are. KOA is running HD, or at least was, man the sidebands are ferocious at that location, even if the analog is weak. Same with another Denver, I think 560. Really loud sidebands, weak analog. I think KGYN Guymon OK complained a lot about WOAI sidebands before WOAI shut down the system. I know the WOAI sidebands were really strong in Dallas, it is a wonder 1190 didn't complain.