iHeart owned station here HD/iBOC transmitter is causing adjacent interference way outside their spectrum. How do I get them to fix it?

[pclover]

So there is an iHeart station that looks like this on a SDR waterfall and is splattering into adjacent stations. They had a similar issue last year but it was resolved I believe after a informal FCC complaint. Last time it was so bad that the HD sidebands were buried in and didn't work. This is not SDR overload.

It appears once again it's back and they really don't have a public engineering contact info.

Any ideas? I'm not a station owner but clearly this is not FCC compliant. Why I care is for the upcoming Sporadic-E FM broadcast DX season.

EDIT: Also I attached what it looked like last year before they fixed it.

 

[PTBoardOp94]

Looks right to me. The authorized HD sideband is up to +- 200 kHz from the carrier, and that appears to be exactly what this station is using.

 

[pclover]

Looks right to me. The authorized HD sideband is up to +- 200 kHz from the carrier, and that appears to be exactly what this station is using.

Look at the noise spike around 92 Mhz. That's almost 700 Khz from 92.7. Also 93.3 This isn't local noise.

 

[lanceventa]

If its causing interference to legitimate (a web SDR doesn't count) over the air reception of another station inform that station to pursue it.

 

[pclover]

If its causing interference to legitimate (a web SDR doesn't count) over the air reception of another station inform that station to pursue it.

Local SDR here not remote. Using a 4 element yagi.

I guess I could contact the adjacent stations to deal with it. 91.9 is getting adjacent interference and is local so I could try that.

 

[lanceventa]

Local SDR here not remote. Using a 4 element yagi.

I guess I could contact the adjacent stations to deal with it. 91.9 is getting adjacent interference and is local so I could try that.

How close to you are the supposedly interfering stations? Hurting DXers from a distance is not going to be a priority, but if its affecting local listening that's another story.

 

[pclover]

How close to you are the supposedly interfering stations? Hurting DXers from a distance is not going to be a priority, but if its affecting local listening that's another story.

About 30 miles however it's a clear line of sight path over water.

Local listening of 91.9 not impossible but the noise is clearly present. It's also around the same distance and a clear shot over water.

 

[Kelly A]

Couple thoughts on this whole thread:
1. Using a consumer grade SDR and a 4 element yagi cut to an undisclosed frequency is not grounds for assuming this station is doing anything wrong. Besides factors with your setup; water reflections and inversion layers can cause multipath, creating inaccurate measurements. If this is bothering you so much, take your setup on the road and measure the station again with a no-gain antenna (vertical whip) and take your measurement from 1km away from the station.
2. Assuming the radio station is transmitting using an antenna with circular polarity, what polarity are you taking the measurements? Let's assume measurements are being made with your antenna horizontal, then you could be seeing vertical scatter in your consumer grade SDR.
Bottom line really, is who cares anyway? Lance is right. Even if this station is operating outside their technical boundaries, which I doubt, how is this negatively affecting your life?

 

[pclover]

Couple thoughts on this whole thread:
1. Using a consumer grade SDR and a 4 element yagi cut to an undisclosed frequency is not grounds for assuming this station is doing anything wrong. Besides factors with your setup; water reflections and inversion layers can cause multipath, creating inaccurate measurements. If this is bothering you so much, take your setup on the road and measure the station again with a no-gain antenna (vertical whip) and take your measurement from 1km away from the station.
2. Assuming the radio station is transmitting using an antenna with circular polarity, what polarity are you taking the measurements? Let's assume measurements are being made with your antenna horizontal, then you could be seeing vertical scatter in your consumer grade SDR.
Bottom line really, is who cares anyway? Lance is right. Even if this station is operating outside their technical boundaries, which I doubt, how is this negatively affecting your life?

It's a yagi tuned for FM broadcast... If i turn the yagi away from the station the noise begins to disappear.

Why I care is DX interference obviously not an issue to normal listening, but splatter into adjacent licensed stations this bad is not acceptable. That's the grounds to them to fix it.

If you look at my OP previously, the station had noise so bad the the HD sidebands wouldn't lock. Even on a Sony XDR it refused despite a strong signal. When they fixed it the noise was gone and the sidebands locked without issues. Also the noise I'm pointing out now was gone until recently.

Given the similar pattern of the noise and the period it was gone for pretty likely once again their filtering is screwed up some place.

As you pointed out multipath and scatter obviously are a concern but this is straight line path without much to cause it. Multipath and scatter normally has a very distinct pattern if it's bad on a FFT display.

 

[Kelly A]

It's a yagi tuned for FM broadcast... If i turn the yagi away from the station the noise begins to disappear.

FM broadcast is a pretty wide chunk of spectrum there Skippy. Are you aimed horizontally or vertically? You said over water, so how do you account for inversion and reflections over water?

Why I care is DX interference obviously not an issue to normal listening, but splatter into adjacent licensed stations this bad is not acceptable. That's the grounds to them to fix it.

Do you actually hear splatter? Or are you just relying on your toy SDR?

If you look at my OP previously, the station had noise so bad the the HD sidebands wouldn't lock. Even on a Sony XDR it refused despite a strong signal. When they fixed it the noise was gone and the sidebands locked without issues. Also the noise I'm pointing out now was gone until recently.

If you're talking about something at 92kHz., did it ever occur to you that could be an intentional 92kHz subcarrier?

Given the similar pattern of the noise and the period it was gone for pretty likely once again their filtering is screwed up some place.

What filtering? Do you have any idea what you're talking about?

As you pointed out multipath and scatter obviously are a concern but this is straight line path without much to cause it.

You mean like several miles over water? Yeah, that could be a problem.

Multipath and scatter normally has a very distinct pattern if it's bad on a FFT display.

What does a display have to do with received multipath?

 

[pclover]

FM broadcast is a pretty wide chunk of spectrum there Skippy. Are you aimed horizontally or vertically? You said over water, so how do you account for inversion and reflections over water?

Do you actually hear splatter? Or are you just relying on your toy SDR?

If you're talking about something at 92kHz., did it ever occur to you that could be an intentional 92kHz subcarrier?

What filtering? Do you have any idea what you're talking about?

You mean like several miles over water? Yeah, that could be a problem.

What does a display have to do with received multipath?

In this case I'm doing horizontal The station is circular polarized like most.

You can clearly see there is splitter into adjacent channels. Local 91.9 is noisy as a result. 93.3 is tropo and not local. On a receiver like a Sony XDR it hides it because of DSP noise reduction. AFIK Scatter and Inversion wouldn't shift a signal down 500 Khz or so.

Not sure where 92 Khz is coming from? Not talking about a MPX subcarrier here.

EVERY transmitter has to have filtering... They are not perfect. Be it external or already built in. This is radio engineering 101. If you didn't you'd have harmonics and/or IMD products up and down way outside your spectrum. Sometimes called spurious emissions. Here is an example of some FM Filters-Combiners Archives - Electronics Research, Inc.

If you look carefully at a FFT display of a spectrum analyzer multipath becomes obvious. That's what I mean by here.

 

[Kelly A]

In this case I'm doing horizontal The station is circular polarized like most.

You can clearly see there is splitter into adjacent channels. Local 91.9 is noisy as a result. 93.3 is tropo and not local. On a receiver like a Sony XDR it hides it because of DSP noise reduction. AFIK Scatter and Inversion wouldn't shift a signal down 500 Khz or so.

But your Chinese SDR is not a calibrated way of measuring this. If you can't hear splatter, then it's likely not there.

Not sure where 92 Khz is coming from? Not talking about the MPX subcarrier here.

But stations are allowed to run 67kHz or 92kHz subcarriers along with HD. The fact you don't know that speaks volumes.

EVERY transmitter has to have filtering... They are not perfect.

Be it external or already built in. This is radio engineering 101.

You clearly have never been a broadcast engineer. More likely just a big talking radio nerd with a Chinese SDR. The fact you can't articulate what filter and where, illustrates that.

If you didn't you'd have harmonics and/or IMD products up and down way outside your spectrum. Sometimes called spurious emissions. Here is an example of some FM Filters-Combiners Archives - Electronics Research, Inc.

But what if this station isn't running through a combiner? Do you even know?
.

If you look carefully at a FFT display of a spectrum analyzer multipath becomes obvious. That's what I mean by here.

But you weren't siting a spectrum analyzer. You were using a cheap Chinese SDR. Not the same Skippy.

Look, here's the bottom line: Amateur know-it-all's like you really chap my ass. I've been a real live broadcast engineer for over thirty years. Occasionally someone like you comes on to the site swinging their cheap SDR around pointing the finger like you're some sort of expert. Over the years I've dealt with people like you. Time and time again, some who complain to the Commission, causing me to waste my valuable time showing they they don't know what they're talking about. There hasn't been one that's been right either. So rather than pissing off experts further with your tripe, I'd be happy to educate you on the way to take real measurements.

 

[TheBigA]

I guess I could contact the adjacent stations to deal with it. 91.9 is getting adjacent interference and is local so I could try that.

I'm reminded of Bob Savage, owner of WYSL Rochester, whose station was being bombarded by HD Radio interference from WBZ in Boston. He did a one man campaign against HD, started the website StopIBOC.com, and complained several times to the FCC about the problems the interference was causing his station. He reported on this board that the FCC basically hung up on him. Ultimately CBS Radio gave up on IBOC-AM. But for years, Bob did everything possible to address this issue and got nowhere. And Bob is a very solid engineer as well as GM.

 

[lanceventa]

But what if this station isn't running through a combiner? Do you even know?
.

It's not. Based on his location, he is talking about 92.7 KTOM-FM interfering with 91.9 KSPB

But you weren't siting a spectrum analyzer. You were using a cheap Chinese SDR. Not the same Skippy.

Look, here's the bottom line: Amateur know-it-all's like you really chap my ass. I've been a real live broadcast engineer for over thirty years. Occasionally someone like you comes on to the site swinging their cheap SDR around pointing the finger like you're some sort of expert. Over the years I've dealt with people like you. Time and time again, some who complain to the Commission, causing me to waste my valuable time showing they they don't know what they're talking about. There hasn't been one that's been right either. So rather than pissing off experts further with your tripe, I'd be happy to educate you on the way to take real measurements.

@Kelly A - I understand your frustration with the time you've had to deal with others in similar situations and as stated earlier in the thread agree that he has no foundation to complain on, but as someone who started this site as a know-nothing teenager, I don't think the attitude towards someone who did come here in my mind looking to learn is warranted. In an industry where we definitely need to do a better job of recruiting and developing the next generation of talent and in particular engineers, a proper response could help @pclover learn as opposed to resorting to name calling.

Me and my teenaged peers dealt with the same in the early years of this site, and yet despite of that I know fellow young posters who have gone on to become SVP's, station owners, and even educators teaching broadcasting.

 

[pclover]

I'm reminded of Bob Savage, owner of WYSL Rochester, whose station was being bombarded by HD Radio interference from WBZ in Boston. He did a one man campaign against HD, started the website StopIBOC.com, and complained several times to the FCC about the problems the interference was causing his station. He reported on this board that the FCC basically hung up on him. Ultimately CBS Radio gave up on IBOC-AM. But for years, Bob did everything possible to address this issue and got nowhere. And Bob is a very solid engineer as well as GM.

IBOC AM is okay during the day but at night it's a nuisance due to skip. Not sure why it's been approved for night use...

 

[TheBigA]

IBOC AM is okay during the day but at night it's a nuisance due to skip. Not sure why it's been approved for night use...

That's what Bob said. It got him nowhere, and he's a station owner.

 

[pclover]

It's not. Based on his location, he is talking about 92.7 KTOM-FM interfering with 91.9 KSPB

@Kelly A - I understand your frustration with the time you've had to deal with others in similar situations and as stated earlier in the thread agree that he has no foundation to complain on, but as someone who started this site as a know-nothing teenager, I don't think the attitude towards someone who did come here in my mind looking to learn is warranted. In an industry where we definitely need to do a better job of recruiting and developing the next generation of talent and in particular engineers, a proper response could help @pclover learn as opposed to resorting to name calling.

Me and my teenaged peers dealt with the same in the early years of this site, and yet despite of that I know fellow young posters who have gone on to become SVP's, station owners, and even educators teaching broadcasting.

@Kelly A Does have point obviously I'm not using lab grade equipment with calibrated antennas etc. That could easily run 6 or even 7 figures. However, I'm not using a rtl-sdr but rather a SDR-Play which does some front end filters.

They believe I'm probably seeing IMD or an IF image instead of a actual signal which is valid and fair criticism. Or perhaps maybe a signal reflection in the coax. The RTL-SDR is very prone to IF images and other RF problems. However, I don't believe that's the case here. I don't believe it's local noise as well.

Consumer SDR stuff has got really good over the years and is become far better then cheap toys. Of course some of them don't have in-line filters and you have to deal with that externally. Will it beat a $40,000 spectrum analyzer tho? Of course not.

 

[davideduardo]

@Kelly A - I understand your frustration with the time you've had to deal with others in similar situations and as stated earlier in the thread agree that he has no foundation to complain on, but as someone who started this site as a know-nothing teenager, I don't think the attitude towards someone who did come here in my mind looking to learn is warranted. In an industry where we definitely need to do a better job of recruiting and developing the next generation of talent and in particular engineers, a proper response could help

I agree that some tolerance and guidance is needed. We do, however, seem to get our more-than-fair-share of people who jump to conclusions before they ask for guidance, opinions and comments.

A post positioned as, "I did this and found this result..." with question about whether the person is viewing this correctly would be better than accusing the station of bad engineering practices.

We see this more often in the "I just love Purple Fruitcake's new song, but I guess the PD at Zip 107 FM did not get payola so they are not playing it." That's is why I feel at times I need a couple of verbose/detailed macros to explain how actual stations select, rotate and play songs.

Me and my teenaged peers dealt with the same in the early years of this site, and yet despite of that I know fellow young posters who have gone on to become SVP's, station owners, and even educators teaching broadcasting.

I always had a policy at stations I owned or managed that we would try to satisfy "can I have a tour" visitor. It wins lots of points with the listener, and it forces staff to actually talk to someone who is not an insider or a prize pig at a station event.

Of course, when I was about 13 I visited Don Burden's station in Denver. I got a tour from a nice staff members, but in going around the corner in a hall, I walked right in to Burden himself. "Who's this little c--ck--er? Get him out of my station right now and get back to work".

Appropriately, Burden was rewarded some years later with a batch of license revocations. I guess the FCC did not want that "big c--ck--er" occupying the radio dial.

 

[davideduardo]

I'm reminded of Bob Savage, owner of WYSL Rochester, whose station was being bombarded by HD Radio interference from WBZ in Boston.

Has anyone any news or update on Bob? He used to be a regular poster here. I seldom agreed with him, but he had a valuable array of concerns and opinions.

 

[pclover]

That's what Bob said. It got him nowhere, and he's a station owner.

Yeah not surprising. Not sure what the state is of AM iBOC these days but it doesn't seem like it's vastly popular as it once was.