There's background noise in my signal.

[wnmb]

For the past couple of weeks, there's been a noise in my on air audio in the night and early morning hours. Although I am posting here, I am not blaming anyone or anything. I am instead, hoping, those of you familiar with IBOC, which I am not, might help me rule it out as a culprit.
The noise is sort of like a hiss which is about the same level all the time. I am providing a link here so that you can listen. I suggest using the link rather than typing it yourself because it is case sensitive.

http://www.waynesweb.com/WNMB728am.mp3

Here are particulars. The background noise is noticeable at night and through the critical hours. During the daytime, I believe our signal is covering it up.
This piece was recorded using a Sony SRF-A100 receiver. The receiver was located at our studios. It's about 5 air miles from our transmitter and tower site. We broadcast with 500 watts at AM 900 24 hours a day. This piece was recorded at 7:28 a.m. on 24 Sept. 2007; just past sunrise here and critical hour time.
We use the Sony as an "air" monitor and we have several such radios. They all sound the same in relation to the noise.
Now, we hear some noise from time to time anyway. such things as thunderstorms and sometimes man made interference which can be identified. This appears to be something different.
Other info; our audio chain is clean. There's no noise in the studio, stl, optimod or transmitter audio stages. All is clean. All sounds great all the time within a couple of miles of the towers. I will be happy to answer any questions or provide more info. Any ideas? Bill. wnmb

 

[rbrucecarter5]

I suspect a WLS IBOC sideband. The hiss sounds exactly like IBOC hash. There is something else mixed in, though, that sounds a bit like a heterodyne - but no unusual transatlantic has been noted recently.

Here is a test - take one of your portables outside and turn it outside so there is a null towards Chicago. If the hiss goes away, you have your culprit.

 

[JohnnyElectron]

Bill, first of all - I'm glad to see that there's an AM broadcaster that cares enough about their audio to transmit in stereo (that a whole lot of car radios can still receive too), and your audio sounds damn fine - (except for the hiss).

I agree with rbc5: try going outside and see if you can null the hiss and see what's inline with your ferrite bar antenna, which direction nulls out the hiss. Also, WLS doesn't always run IBOC - and sometimes runs CQuam, so post on here when it goes AWAY - then we can scan WLS up here and see if their IBOC is on or off. There's also 50KW WFDF Detroit, but they are throwing their flames primarily to the North, so WLS would be a first stop to see if it's related.

Great audio there - hard to believe that it's off-air it's so good.

 

[Chuck]

Great audio there - hard to believe that it's off-air it's so good.

It is really good audio under all that noise. I'm impressed. I wish our local AM's sounded as good (without the noise of course). The hiss and whine sound is very similar to the adjacent channel IBOC noise I've reported on both AM and FM stations in the Dallas area.

I won't tell you that is what is causing it, but is appears distinctly possible that you are being clobbered by someone else's HD.

 

[Mike Walker]

A spectacular example of how good AM Stereo can (and did) sound at well engineered stations! I hate to admit it, but it seems to me that the most likely cause is IBOC hash from WLS. Is this what's gonna' happen to local radio when there are tons of HD AM stations? Of course most AM radios exhibit much narrower bandwidth than the SRF-A100, but the noise SOUNDS like it would be in the passband of a narrower radio (it's not really high pitched). Hmmm. Now THIS I CAN HEAR! I've never heard any such interference from FM HD.

 

[vsa]

For the past couple of weeks, there's been a noise in my on air audio in the night and early morning hours. Although I am posting here, I am not blaming anyone or anything. I am instead, hoping, those of you familiar with IBOC, which I am not, might help me rule it out as a culprit.
The noise is sort of like a hiss which is about the same level all the time. I am providing a link here so that you can listen.  I suggest using the link rather than typing it yourself because it is case sensitive.

http://www.waynesweb.com/WNMB728am.mp3

Here are particulars.  The background noise is noticeable at night and through the critical hours.  During the daytime, I believe our signal is covering it up.
This piece was recorded using a Sony SRF-A100 receiver.  The receiver was located at our studios. It's about 5 air miles from our transmitter and tower site.   We broadcast with 500 watts at AM 900 24 hours a day. This piece was recorded at 7:28 a.m. on 24 Sept. 2007; just past sunrise here and critical hour time.
We use the Sony as an "air" monitor  and we have several such radios.  They all sound the same in relation to the noise.
Now, we hear some noise from time to time anyway. such things as thunderstorms and sometimes man made interference which can be identified. This appears to be something different.
Other info;  our audio chain is clean.  There's no noise in the studio, stl, optimod or transmitter audio stages. All is clean.  All sounds great all the time within a couple of miles of the towers. I will be happy to answer any questions or provide more info.  Any ideas?  Bill. wnmb

Bill,

Make sure your representatives in the House and Senate in D.C. are aware of this and have an opportunity to hear this.

Until federal officials come to their senses, you can try compressing the crap out of your wonderful audio until it completely covers up the hissing in more areas. Of course, you'd be losing listeners for a different reason.

You could also do an updated version of what many daytimer AMs with FMs did many many years ago. Set up a HIGHER QUALITY audio stream on your website and treat your website stream like an FM simulcast. Then actively urge your listeners to switch to the Internet stream before each sunset. Of course, the new SoundExchange fees will kill you.

You do have yet another option. Sell the station to an HD radio cartel member for pennies on the dollar.

Oh, one more idea. You could give your format a new name, like "oldies while you sprinkler the lawn" or "oldies while you take a shower."

 

[Savage]

Mike: this is what i'm talking about. THIS is my objection to HD-AM.

Now, imagine your livelihood depends on the presence/absence of that noise on your signal. You have nothing to do with it. It's just summarily imposed on you.

We just completed a two-week 100-man-hours study of adjacent-channel IBOC interference to WYSL, involving 31 field measurements and audio recordings, representing over 700 miles of driving. It's over ten pages long.

Since we're trying to resolve the interference issue it's not appropriate to release it to the general public right now. Suffice it to say: it makes the WNMB situation, as bad as that is, seem like nothing.

 

[RememberWHEN]

Bill - Yep, that sure sounds like the "signature" of that masked bandit IBOC!! JohnnyElectron is correct - WLS has not been and has been IBOC'g at night since the official "kick off". Here's an idea -- can't say that he will or won't cooperate -- but you might contact the chief at 'LS and find out if they are still alternating (and when). With any luck and similar propagation conditions you could have some BEFORE and AFTER recordings indicating what your signal sounds like without and with the masked bandit. Chief is Warren Schultz. Sorry, I do not have any contact information.

 

[Mike Walker]

If the engineer at WLS is a good guy, you might even get him on the phone, and have him switch the HD off while you listen. This should answer the question (we're all wondering)...is that the source of the noise? Hell, I'd bet lunch the guys at WLS would love to know the answer as well. You might consider forwarding your mp3 to the chief engineer at WLS (ABC Chicago) and ask if there's a time you could talk on the phone (at a time when your signal is being affected) and switch the HD off just a few seconds to see if it's the cause.

Now, if WLS switches HD off, and the noise remains...well you REALLY have a mystery! Speaking of mysteries, SOMETHING in my neighborhood has been generating a "pop, pop, pop" sound at slightly less than one second intervals for months. I've walked my neighborhood with an AM radio tuned to a spot on the dial where the noise is most obvious...hundreds of yards in every direction, and I'll be damned if I can figure out what it is. It's driving me NUTS!

 

[Savage]

Bill - while you're at it - if you can persuade WLS to do the experiment with you, be sure you have a digital recorder rolling patched into your air monitor at the time. As him to give it an on-off cycle or two as you record. Note the time of day, weather conditions, and measure your field strength at the receiver location.

 

[SUPERCASTER]

If the engineer at WLS is a good guy, you might even get him on the phone, and have him switch the HD off while you listen. This should answer the question (we're all wondering)...is that the source of the noise? Hell, I'd bet lunch the guys at WLS would love to know the answer as well. You might consider forwarding your mp3 to the chief engineer at WLS (ABC Chicago) and ask if there's a time you could talk on the phone (at a time when your signal is being affected) and switch the HD off just a few seconds to see if it's the cause.

Now, if WLS switches HD off, and the noise remains...well you REALLY have a mystery! Speaking of mysteries, SOMETHING in my neighborhood has been generating a "pop, pop, pop" sound at slightly less than one second intervals for months. I've walked my neighborhood with an AM radio tuned to a spot on the dial where the noise is most obvious...hundreds of yards in every direction, and I'll be damned if I can figure out what it is. It's driving me NUTS!

I believe you started posting about this loud popping noise problem after getting the Radio Shack HD Accurian radio.

 

[wnmb]

I appreciate everyone's comments and ideas. We are working on it. In contrast, here is another audio clip for you. This one was recorded a little earlier in the day on Sept. 25. There's much less of the hiss. This is a better example of what the AM Stereo really can do for a station. It was recorded under the same circumstances as the previous audio. It's a Sony SRF A-100 sitting in our studio and its output goes to one of our computers where it was recorded on SAW. No effects were used in the SAW program; it's just the straight audio from the Sony.
This one is a jingle and a full song, which does a good job highlighting the Stereo separation.

http://www.waynesweb.com/WNMB92507.mp3

 

[clouseau]

SOMETHING in my neighborhood has been generating a "pop, pop, pop" sound at slightly less than one second intervals for months. I've walked my neighborhood with an AM radio tuned to a spot on the dial where the noise is most obvious...hundreds of yards in every direction, and I'll be damned if I can figure out what it is. It's driving me NUTS!

I believe you started posting about this loud popping noise problem after getting the Radio Shack HD Accurian radio.

Good Point. I've had a similarly relevant experience in that my riding lawn mower has stopped shifting into reverse about 5 months after getting an Accurian. I have the same experience as Mike, too. Even getting several Hundred yards away doesn't help. Who'da thunk it?

Or maybe Mike has an Electric fence nearby. (Or NOT so nearby). That might also be the culprit.

Clouseau

 

[SUPERCASTER]

SOMETHING in my neighborhood has been generating a "pop, pop, pop" sound at slightly less than one second intervals for months. I've walked my neighborhood with an AM radio tuned to a spot on the dial where the noise is most obvious...hundreds of yards in every direction, and I'll be damned if I can figure out what it is. It's driving me NUTS!

I believe you started posting about this loud popping noise problem after getting the Radio Shack HD Accurian radio.

Good Point. I've had a similarly relevant experience in that my riding lawn mower has stopped shifting into reverse about 5 months after getting an Accurian. I have the same experience as Mike, too. Even getting several Hundred yards away doesn't help. Who'da thunk it?

Or may be Mike has an Electric fence nearby. (Or NOT so nearby). That might also be the culprit.

Clouseau

I believe Mike said he had already checked out that problem, and the interference is still there even when the fence nearby is off. Are you saying the fence still causes interference even when the power is off?
Someone here posted there is no interference anywhere unless the FCC says there is!

 

[Mike Walker]

Yes Supercaster, I did notice the popping after I got the Accurian. Months after. Suspecting some electrical/electronic device on my property, I have completely taken my house "off the grid" (turning off all power to the house/pump/etc at the switchbox), then walking around my property/neighborhood. The popping is still there.

I thought it was the electric fence. Problem is, the sound is no louder when I place my radio almost against the fence than it is 100 yards away. Probably not the fence!

One thing that HAS changed in the last six months is that a new home has been constructed next to my property (replacing a very old home that was torn down), and a family has moved in. Perhaps a security system or something ("invisible fence" for a dog that sometimes stays with them?) could cause this?

 

[Mike Walker]

Clouseau, darned if my riding lawnmower hasn't exhibited the same symptoms since I got the Accurian. It MUST be the culprit (thanks for the grin!)

 

[w9wi]

For the past couple of weeks, there's been a noise in my on air audio in the night and early morning hours. Although I am posting here, I am not blaming anyone or anything. I am instead, hoping, those of you familiar with IBOC, which I am not, might help me rule it out as a culprit.

If the attenuation of signals by the mountains in the easterly direction is anything like it is in the westerly, I don't think WLS is the culprit. WCBS, on the other hand, I would believe. Any strong stations on 910 or 920 in your neck of the woods?

Some things I would try: (and you may well have already tried some of these)

- If you carry one of the Sonys to your transmitter at the time in question, it delivers a clean signal? (be certain there isn't something going on that your mod monitor doesn't see but the Sonys do...)
- You're *certain* the noise goes away during the day? (I would suggest intentionally running a few seconds of dead air around noon)
- What happens in other parts of town - away from your studios but a similar distance from the transmitter? (noting that you're a directional station you'll also have to take that into effect & choose a site where your signal should be of similar strength) Are you certain there isn't some source of noise at your studio? (unshielded computer, something like that)
- (are your listeners noticing this?)
- Can you borrow a communications ("ham") receiver? If WCBS-HD is the source, the noise should only be on your *lower* sideband - if you tune to 900KHz upper sideband it should be clean.

IBOC certainly does seem like a plausible source here, but I'd want to be certain that was what it was before trying to do anything about it.

 

[R.F. Burns]

For the past couple of weeks, there's been a noise in my on air audio in the night and early morning hours. Although I am posting here, I am not blaming anyone or anything. I am instead, hoping, those of you familiar with IBOC, which I am not, might help me rule it out as a culprit.

If the attenuation of signals by the mountains in the easterly direction is anything like it is in the westerly, I don't think WLS is the culprit. WCBS, on the other hand, I would believe. Any strong stations on 910 or 920 in your neck of the woods?

Some things I would try: (and you may well have already tried some of these)

- If you carry one of the Sonys to your transmitter at the time in question, it delivers a clean signal? (be certain there isn't something going on that your mod monitor doesn't see but the Sonys do...)
- You're *certain* the noise goes away during the day? (I would suggest intentionally running a few seconds of dead air around noon)
- What happens in other parts of town - away from your studios but a similar distance from the transmitter? (noting that you're a directional station you'll also have to take that into effect & choose a site where your signal should be of similar strength) Are you certain there isn't some source of noise at your studio? (unshielded computer, something like that)
- (are your listeners noticing this?)
- Can you borrow a communications ("ham") receiver? If WCBS-HD is the source, the noise should only be on your *lower* sideband - if you tune to 900KHz upper sideband it should be clean.

IBOC certainly does seem like a plausible source here, but I'd want to be certain that was what it was before trying to do anything about it.

WCBS AM has not been running their IBOC at night due to Yankees game broadcasts. WRKL, 910 Khz tried to take on WCBS with an FCC filing. WCBS proved that they are totally within the law and caused no interferenece to the WRKL signal within their protected area. What is funny is that in a metro area the size of NYC WRKL is trying to serve a Polish speaking population in Brooklyn that is over 35 miles away with a 1 Kw transmitter. WRKL's signal barely makes it to Manhattan which is maybe 28 air miles from Pomona, NY (Their transmitter/studio site). The other part of the RKL filing was that brought a grin was that they used a map from Radio-Locator in their FCC petition to represent their pattern. Of course on each of the Radio-Locator maps they make the following statement; "This image is intended solely for entertainment purposes. Radio-Locator makes no claims as to the accuracy of this information, nor towards its suitability for any intended purpose". The FCC dismissed their filing. By the way, the FCC hasn't renewed the license for WRKL which expired in June of 2006. A better answer to people who are experiencing noise is to contact their local utility company. Provide as much information as possible and they will track down the offender. When I had a 5 ele tri-band beam up, I used to suffer occassional interference which I was able to track to specific areas by turning my beam. The local power company always resolved the noise issues which were tracked to faulty power transformers or cracked insulators.

 

[Chuck]

Clouseau, darned if my riding lawnmower hasn't exhibited the same symptoms since I got the Accurian. It MUST be the culprit (thanks for the grin!)

Geez... It must be catching. Shortly after I got my HDT-1 the brakes stopped working on my riding mower. I'm glad I didn't get an Accurian, because right now, I just put it in reverse to stop it!

 

[Savage]

Hold the First Phone: isn't WNMB on 900 kHz? WCBS shouldn't be a factor with IBOC as second-adjacent. The fact that it seems worst in morning suggests skywave arriving from the west, which would make me suspect WLS. Second the sentiment about somebody nearby (like within 80 miles or so) on 910 who might be running IBOC.

Check with your consultant or CE about the extent of your nighttime and daytime interference-free contours. The night will be specified in your license or CP application; the daytime is 0.5 mv/m.