unknown Interference problem

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billob

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I am posting on this forum because support suggested that I use this one.

f I should be using another forum, please let me know which one it is

My device is a RCA RF 900 MHZ wireless speaker system that was sold by Radio Shack back around Y2K.

For over a year now I have been getting a pop...pop...pop that fir all intents and purposes sounds like a phonograph needle that is caught in a record groove. It occurs at a rate of about 80 pops per minute with occasional rapid bursts of 10-15 pops.

I have carried my speakers to the limit of their range (about a block) with no effect on the problem.

Changing the direction the speakers are pointed also has no effect on the problem


I have powered down the entire house with the exception of the circuit that my device is on with no effect on the problem which occurs most of the time for 24 hours every day.

I have also tried removing the batteries from household devices like smoke detectors and my cordless phones.

It is more pronounced during the late night hours

The transmitter for these speakers is connected to a stereo system. The interference is present no matter what the input source to the transmitter from my stereo amp is, that is TV, FM, CD player, Tape player, Phonograph etc. The noises come even when there is no audio being sent like during the dead spot between record or CD tracks although the carrier is still present and being received by the speakers
.
The noise DOES NOT does show up in the speakers that are connected to my stereo amp's speaker terminals..

It's like the transmitter itself is picking up a stray signal coming over the air and rebroadcasting it to my speakers.

The transmitter uses a 19 vdc supply that plugs into the wall. Each speaker has it's own 6 vdc supply
Each speaker will also operate off of an internal battery. Switching the speakers to battery power is of no help.

I tried contacting the electric company who does not seem interested in my problem.

What devices are out there that operate around 900MHZ that could be causing this and how can I track down the problem device?

I would appreciate suggestions on how to locate the source of this interference.
 

Jimru

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I am posting on this forum because support suggested that I use this one.



f I should be using another forum, please let me know which one it is



My device is a RCA RF 900 MHZ wireless speaker system that was sold by Radio Shack back around Y2K.



For over a year now I have been getting a pop...pop...pop that fir all intents and purposes sounds like a phonograph needle that is caught in a record groove. It occurs at a rate of about 80 pops per minute with occasional rapid bursts of 10-15 pops.



I have carried my speakers to the limit of their range (about a block) with no effect on the problem.



Changing the direction the speakers are pointed also has no effect on the problem





I have powered down the entire house with the exception of the circuit that my device is on with no effect on the problem which occurs most of the time for 24 hours every day.



I have also tried removing the batteries from household devices like smoke detectors and my cordless phones.



It is more pronounced during the late night hours



The transmitter for these speakers is connected to a stereo system. The interference is present no matter what the input source to the transmitter from my stereo amp is, that is TV, FM, CD player, Tape player, Phonograph etc. The noises come even when there is no audio being sent like during the dead spot between record or CD tracks although the carrier is still present and being received by the speakers

.

The noise DOES NOT does show up in the speakers that are connected to my stereo amp's speaker terminals..



It's like the transmitter itself is picking up a stray signal coming over the air and rebroadcasting it to my speakers.



The transmitter uses a 19 vdc supply that plugs into the wall. Each speaker has it's own 6 vdc supply

Each speaker will also operate off of an internal battery. Switching the speakers to battery power is of no help.



I tried contacting the electric company who does not seem interested in my problem.



What devices are out there that operate around 900MHZ that could be causing this and how can I track down the problem device?



I would appreciate suggestions on how to locate the source of this interference.

Do you have a scanner (or any receiver) that receives in that frequency range? That would be one place to start. Find out what exact frequency your speakers use and see if you can tune that in on the scanner/receiver. If you don't have radios that receive in that range, can you borrow one from someone you know?
 

RFI-EMI-GUY

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900 MHz ISM band is filled with potential interferers

Do you live by a military base?

Has a utility changed you electrical power or water meter to one of the new digital ones that reports consumption wirelessly?

Do you live near a tollway or freeway where toll pass RFID might be read?

Do you or a neighbor have a 900 MHz cordless phone?
 

billob

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I have one of those meters but it has been in service for several years, way before my problem started.
 

mmckenna

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Where is your mobile phone when you are hearing this interference?

Sounds a whole lot like what my iPhone does when I get it too close to computer speakers. For that matter, what my work 800MHz portable does when it's sitting on my desk. When the radio transmits, the computer speakers will "pop".
When the cell phone is too close, it's a bunch of clicks that sounds about like what you are describing.
 

ScannerSK

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It is possible the receive or transmit frequency has drifted off slightly so they are not tuned into each other correctly anymore; this can happen as units like these age. If this is the case, the system will have the same problem no matter where it is used (different house, different town, etc.)
 

kruser

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Several wireless weather stations also use the ISM band.
Most everything (except wireless speakers or headphones) must use a form of frequency hopping spread spectrum today if using the license free ISM band.

The other suggestion from another is also a good one that another radio may be scanning a channel that is causing interference.
If you do have another radio scanning, try turning it off and see if the interference stops. If so, turn it back on and try stepping through each channel it scans manually until you hit one that causes a constant carrier in your speakers. That's more common when using say a cable TV splitter to run several scanners from a single antenna but I have seen several scanners over the years that had a local oscillator that emitted a signal strong enough to be picked up a couple hundred feet or more away.

I apologize if I missed it but I think those speakers allowed you to set them for three different frequencies. Have you tried changing the transmitter and speakers to one of the other available channels?
 

billob

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Thanks folks.

I unplugged power to cordless phones.

I can change freq on my xmitter & follow it with the speakers, I cannot set a specific freq.

I have no idea if any locals have 900mhz cordless phones.

I have only land line...no cells

digital power meter came years ago. also it blinks at a much faster rate than my interference.

No tollways in phx.

No bases nearby.

Sorry, no access to a scanner..Is that something that I could possibly rent?

Years ago I had a TVI problem & the power Co came out with some sort of a receiver and quickly traced it to a loose ground on a nearby power pole. Can't happen now since everything went underground about 15 years back.

Please keep those hints coming. Sooner or later we will get lucky.
 

Jimru

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It is possible the receive or transmit frequency has drifted off slightly so they are not tuned into each other correctly anymore; this can happen as units like these age. If this is the case, the system will have the same problem no matter where it is used (different house, different town, etc.)


That would be a good way to test! Take the system to another location far away from his house and test. I didn't consider that!
 

mmckenna

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Years ago I had a TVI problem & the power Co came out with some sort of a receiver and quickly traced it to a loose ground on a nearby power pole. Can't happen now since everything went underground about 15 years back.

Please keep those hints coming. Sooner or later we will get lucky.
Unlikely it's power company related. Usually those sorts of issues are a random noise caused by arcing, and that can change with weather, humidity, wind, etc.

I don't know of any place to "rent" a scanner, sometimes you can find a local that would be willing to help. Better than a scanner would be a spectrum analyzer, but they require some skill, are expensive to rent, and without the skill it would be pointless.

Before chasing this too far, consider the cost of a new pair of speakers. As stated above, these are 16 years old and it could just be an internal failure.
 

Jimru

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Thanks folks.



I unplugged power to cordless phones.



I can change freq on my xmitter & follow it with the speakers, I cannot set a specific freq.



I have no idea if any locals have 900mhz cordless phones.



I have only land line...no cells



digital power meter came years ago. also it blinks at a much faster rate than my interference.



No tollways in phx.



No bases nearby.



Sorry, no access to a scanner..Is that something that I could possibly rent?



Years ago I had a TVI problem & the power Co came out with some sort of a receiver and quickly traced it to a loose ground on a nearby power pole. Can't happen now since everything went underground about 15 years back.



Please keep those hints coming. Sooner or later we will get lucky.


I think the suggestion of moving the system to another location that ScannerSK mentioned is the best so far. Try several locations not in your neighborhood, if that is possible (friends or relatives?).

It may also be the quickest way to determine if the speaker system itself is at fault or not.

If the unit has the same symptoms no matter where you go, then most likely it's being caused by the speaker and transmitter itself.

If that is the case, I would suggest buying a new speaker system, because no one repairs these types of consumer products unless they are under warranty.
 

JamesO

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Move the system to a totally different location, friend or families house blocks or miles away and see what happens. This is the easiest way to rule out the system or a local problem.
 

Jimru

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Oi, Jimru - you don't need to quote all of the OP's text when you reply - thanks :)

I don't know how else to do it! I use the Tapatalk app for all of my forums, and I've never seen a way to select just a portion of a post, Majoco.
 

dlwtrunked

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I have one of those meters but it has been in service for several years, way before my problem started.
Despite what you have said, I bet it is the meter. These operate very near 900 MHz. on several channels. They may have changed yours (you would not know) or a neighbors meter with one on a different channel that now interferes. Your description matches what these would sound like. If that is the case, there is nothing you can do.
 

majoco

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Hi Jimru,

I don't know how else to do it! I use the Tapatalk app for all of my forums, and I've never seen a way to select just a portion of a post,
Well, I don't know what Tapatalk does, but here's how it's done on a computer...

Highlight the portion of text you want to copy by dragging your mouse pointer or stylus over it and click on 'copy'.
Open a new "reply" box, type "
", click on 'paste', type
and "enter for a new line. Done

So that's "square bracket left" "quote" " Square bracket right " then the inserted text, then "/" "square bracket left" "quote" "square bracket right" "enter"

I'll make a mistake and see if it shows it clearer..

text here [/quote ]
No, doesn't work but you get the idea - just do what you are doing now but just cut a portion of the text you want by highlighting and clicking on 'paste' or "CTRL C"
 
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Jimru

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Majoco, I'll check it out, but I really prefer using Tapatalk for these forums, so I'll prolly just refer to points in someone else's posts, rather than direct quoting if that's the case. Maybe Tapatalk will unveil a newer version where I can more simply highlight only needed portions rather than the whole post.

You are right, it's cumbersome to include the whole quote!
 

majoco

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I don't know how far up the frequency spectrum that interference goes, but I took my Kenwood R2000 HF receiver out to a farmers paddock where the was a swamp at the bottom and ran out a long length of telephone wire about 6ft off the ground and plunged my earth rod into the mud, hoping to hear all sorts of signals. All I heard in the main was three or more electric fence units which the noise blanker couldn't cope with. :)
 

kruser

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I don't know how far up the frequency spectrum that interference goes, but I took my Kenwood R2000 HF receiver out to a farmers paddock where the was a swamp at the bottom and ran out a long length of telephone wire about 6ft off the ground and plunged my earth rod into the mud, hoping to hear all sorts of signals. All I heard in the main was three or more electric fence units which the noise blanker couldn't cope with. :)
I have experience with electric fences, being zapped by them and them causing horrible noise in my HF radios and low band VHF on the scanners. :)
 

billob

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OK folks:

Like I said back on 11-29-16, we might get lucky.

We did.....sort of.

Over one year after my first complaint to the power company, I tried again and they responded.

The source of my BCI is apparently is an inverter that is part of a solar panel setup on a house on a cul-de-sac about a block away from my location. The problem is, they cannot track it to the exact house because that would require shutting down power to each house until they find the right one.

Since this is not a problem with their (the power company's) equipment. they do not have the power (no pun intended) to go inside or shut down power to any of those properties to determine the exact source of this interference.

Suggestions on how to proceed in this matter will be appreciated.
 
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