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Noise
May 22, 2014 10:22:44 GMT -5
Post by BladeRunner now OLD FLASH!!!!! on May 22, 2014 10:22:44 GMT -5
You are not alone in the noise department. I've noticed a slow but steady increase in the static and buzzing type noises over the years. I hear it from the AM broadcast band, all the way up though 220 Mhz. I don't know if the cause is mainly from breaking down electrical infrastructure, or from newfangled digital gadgets, or a combination of both. All I know is that driving around mobile and trying to hear weaker stations is getting much harder to do. I can remember back in the 70's, barefoot mobiles could talk to each other at distances up to 10 miles apart. Nowadays, you need 50 - 100 watts to do it. Here is a quote from an old thread that moved to the subject of noise. I remember back in the 60's and 70's there just seemed to be less noise than there is now. I attributed it to being out in the country where my nearest neighbor was half mile away. When there was no skip, it was dead quiet. There was the faint, gentle hiss of the radio and it took almost nothing for someone to be heard. I got out of the hobby because for a long time all I could hear, day and night, was the unbearable squall of hetrodyne noise. Then a few years back, I bought a Mark 3 and traded for a Navaho TRC-458. I lived in the average neighborhood. There was/is a buzzing noise. I assumed it was from an electrical substation about 300 yards away. If I turned my beam in different directions, the noise did change in intensity. Now, I'm 700 further east. I have neighbors, but not as close. I have a different Mark 3 and the same Navaho. I have the same buzz. It's loud and irritating. I have it on both radios. The Navaho seems to clean it up better than the browning, but I guess that's due to the navaho having better noise filtering. Is there anything that can be done (grounding,shielding,whatever) that will help at all. I am in the process of acquiring another beam and coax. I intend routing the coax as far as possible from where my electrical services enters the house. The antenna will be located about 50 feet from the house. Right now I'm on an Antron 99 with that RG8X coax. I realize that's very bad coax. Is there anything else I can look at or do?
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Sandbagger
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Noise
May 22, 2014 17:06:10 GMT -5
Post by Sandbagger on May 22, 2014 17:06:10 GMT -5
Here is a quote from an old thread that moved to the subject of noise. I remember back in the 60's and 70's there just seemed to be less noise than there is now. I attributed it to being out in the country where my nearest neighbor was half mile away. When there was no skip, it was dead quiet. There was the faint, gentle hiss of the radio and it took almost nothing for someone to be heard. I got out of the hobby because for a long time all I could hear, day and night, was the unbearable squall of hetrodyne noise. Then a few years back, I bought a Mark 3 and traded for a Navaho TRC-458. I lived in the average neighborhood. There was/is a buzzing noise. I assumed it was from an electrical substation about 300 yards away. If I turned my beam in different directions, the noise did change in intensity. Now, I'm 700 further east. I have neighbors, but not as close. I have a different Mark 3 and the same Navaho. I have the same buzz. It's loud and irritating. I have it on both radios. The Navaho seems to clean it up better than the browning, but I guess that's due to the navaho having better noise filtering. Is there anything that can be done (grounding,shielding,whatever) that will help at all. I am in the process of acquiring another beam and coax. I intend routing the coax as far as possible from where my electrical services enters the house. The antenna will be located about 50 feet from the house. Right now I'm on an Antron 99 with that RG8X coax. I realize that's very bad coax. Is there anything else I can look at or do? It's very possible that it's something in YOUR house that's generating the noise (since it seemed to follow you to your new home). A simple way to test for this is to put your rig on battery power and then pull the main circuit breaker for the house electric. If the noise goes away, you can start energizing circuits one by one until you find the one causing the noise and then just unplug appliances until you find it. If the noise doesn't go away when you pull the mains, then it's something external and will have to be tracked down with a portable radio or some other means of homing in on the source. If it's something to do with the electric service lines (like a bad insulator), a lot of times you can get the electric company to replace it. Our electric company has a special department that deals with these types of issues and it's headed up by a guy who's a ham, so he's real understanding of the problem of interference.
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Noise
May 23, 2014 17:34:40 GMT -5
Post by BBB on May 23, 2014 17:34:40 GMT -5
We're fortunate to live in the country but still deal with man made noise on the CB from time to time. I was able to identify some of it just as Sandbagger mentioned above by isolating problems in the house, but was also able to ID some power line issues within a mile or so by driving around with the mobile CB. They were arcing out on the bell insulators on the poles. Got the pole numbers and called the local utility company to complain about it mentioning that I was a Ham radio operator. Giving them the pole number really helps them find the issue faster. Another alternative may be to try an external DSP device that helps filter out noise. Here's one that costs around $200. www.westmountainradio.com/product_info.php?products_id=clr_dspFunny that I can remember the same noise in the '70's as a kid with my base set up and I kinda like all the hetrodyne noise for some strange unknown reason. Too much noise sucks though when you're trying to talk local, so I just have to shut it off or select a radio that has good noise filtering. I also think our friends south-O-the border got the memo that CB/ export rigs make good inexpensive business radios because that's ALL I hear during the day. That I don't remember.
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Noise
May 23, 2014 19:23:06 GMT -5
Post by spiderleggs on May 23, 2014 19:23:06 GMT -5
One of my neighbors has one of those modems that uses house wiring as an antenna and it puts 3 to 5 pounds of noise in my radio. Its from about 25mhz up thru the first part of the 10 meter band. I was able to identify what it was by listening to some youtube videos and one played the exact same noise. I can turn my beam and knock it down to about a 1 but the groundplane picks it up full force.
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Sandbagger
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Noise
May 23, 2014 19:32:30 GMT -5
Post by Sandbagger on May 23, 2014 19:32:30 GMT -5
One of my neighbors has one of those modems that uses house wiring as an antenna and it puts 3 to 5 pounds of noise in my radio. Its from about 25mhz up thru the first part of the 10 meter band. I was able to identify what it was by listening to some youtube videos and one played the exact same noise. I can turn my beam and knock it down to about a 1 but the groundplane picks it up full force. I had one of those devices that uses house wiring as a network and it was just BAD. Noise everywhere. Needless to say, I got rid of that and came up with a different solution for my networking issues. But there can be devices like this all over the place, and there isn't much you can do about it. As radio operators we are coming up against the ugly side of the digital age. Most of those digital widgets emit some sort of noise, and the nice quiet noise floors we used to see in the early 70's, unfortunately, are a thing of the past, unless you're lucky enough to own 10 acres of land out in the middle of nowhere......
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Noise
May 24, 2014 4:32:41 GMT -5
Post by BladeRunner now OLD FLASH!!!!! on May 24, 2014 4:32:41 GMT -5
This weekend I am going to kill the house power and run the TRC458 to see if I still have the noise. It's not a hobby killer for me, but I am curious. I do appreciate the discussion. Hopefully I'll have a beam installed before the weekend is over. I'm curious to see if it dies down in different directions.
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Noise
Oct 31, 2014 19:33:38 GMT -5
Post by hotrod on Oct 31, 2014 19:33:38 GMT -5
its been said to me that if a run a flatside beam that kinda manmade noise is much less if not all gone. ive never tried it but if ya got a beam its someting to consider.downside other locals might have to go flatside too unless there really close
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Sandbagger
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Noise
Oct 31, 2014 20:07:41 GMT -5
Post by Sandbagger on Oct 31, 2014 20:07:41 GMT -5
its been said to me that if a run a flatside beam that kinda manmade noise is much less if not all gone. ive never tried it but if ya got a beam its someting to consider.downside other locals might have to go flatside too unless there really close Yes, running on the flatside will reduce man-made noise. It also works better for DX. But very few locals have flatside antennas, and if you run flatside and try to talk to locals who are vertical, there's a 20db loss in signal.
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Noise
Nov 1, 2014 4:21:23 GMT -5
Post by ab5ni on Nov 1, 2014 4:21:23 GMT -5
its been said to me that if a run a flatside beam that kinda manmade noise is much less if not all gone. ive never tried it but if ya got a beam its someting to consider.downside other locals might have to go flatside too unless there really close Yes, running on the flatside will reduce man-made noise. It also works better for DX. But very few locals have flatside antennas, and if you run flatside and try to talk to locals who are vertical, there's a 20db loss in signal. Horizontal polarization (known as flat-side in the CB world) does remove a lot of man-made noise, which is why hams use that polarization. Just guessing, CB probably has about a 75% of its users running mobile, so it's probably a good idea to remain vertically polarized. Networking over house wiring is known as "Broadband Over Powerline," and the FCC has been petitioned by the hams for years to limit its use if not remove it altogether. Unfortunately, powerlines are not shielded in any way, shape, or form, so you'll get the maximum signal and RFI (Radio Frequency Interference) that these things are capable of producing. A lot of big name ISP's want to use this method in rural areas to provide broadband services, and should this ever happen, you can pretty much hangup your mics and forget about playing radio. I seriously doubt that flat-side operation will help in any way. Another really bad source of RFI is florescent and LED lightbulbs. With the use of these things on the rise, the average noise level will rise as well. Guess there is something to be said about incandescent bulbs. 73, Randy AB5NI
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Sandbagger
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Noise
Nov 1, 2014 9:38:05 GMT -5
Post by Sandbagger on Nov 1, 2014 9:38:05 GMT -5
Yes, running on the flatside will reduce man-made noise. It also works better for DX. But very few locals have flatside antennas, and if you run flatside and try to talk to locals who are vertical, there's a 20db loss in signal. Horizontal polarization (known as flat-side in the CB world) does remove a lot of man-made noise, which is why hams use that polarization. Just guessing, CB probably has about a 75% of its users running mobile, so it's probably a good idea to remain vertically polarized. Networking over house wiring is known as "Broadband Over Powerline," and the FCC has been petitioned by the hams for years to limit its use if not remove it altogether. Unfortunately, powerlines are not shielded in any way, shape, or form, so you'll get the maximum signal and RFI (Radio Frequency Interference) that these things are capable of producing. A lot of big name ISP's want to use this method in rural areas to provide broadband services, and should this ever happen, you can pretty much hangup your mics and forget about playing radio. I seriously doubt that flat-side operation will help in any way. Another really bad source of RFI is florescent and LED lightbulbs. With the use of these things on the rise, the average noise level will rise as well. Guess there is something to be said about incandescent bulbs. Noise generation from digital junk, switching supplies and other junk is really becoming a problem, especially when driving around in the mobile. Just about every traffic light is a noise source as well as power lines and other things that I have yet to positively identify. It's pretty bad when it even affects VHF bands. 11 meters is far worse. A far cry from the 1970's when your worst source of noise was spark plugs.
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Noise
Nov 1, 2014 11:05:43 GMT -5
Post by MonkeyMan on Nov 1, 2014 11:05:43 GMT -5
With all these modern noise sources there's a golden opportunity for someone with the know-how to come up with a modern filtering solution.
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Noise
Nov 1, 2014 11:36:00 GMT -5
Post by ab5ni on Nov 1, 2014 11:36:00 GMT -5
Horizontal polarization (known as flat-side in the CB world) does remove a lot of man-made noise, which is why hams use that polarization. Just guessing, CB probably has about a 75% of its users running mobile, so it's probably a good idea to remain vertically polarized. Networking over house wiring is known as "Broadband Over Powerline," and the FCC has been petitioned by the hams for years to limit its use if not remove it altogether. Unfortunately, powerlines are not shielded in any way, shape, or form, so you'll get the maximum signal and RFI (Radio Frequency Interference) that these things are capable of producing. A lot of big name ISP's want to use this method in rural areas to provide broadband services, and should this ever happen, you can pretty much hangup your mics and forget about playing radio. I seriously doubt that flat-side operation will help in any way. Another really bad source of RFI is florescent and LED lightbulbs. With the use of these things on the rise, the average noise level will rise as well. Guess there is something to be said about incandescent bulbs. Noise generation from digital junk, switching supplies and other junk is really becoming a problem, especially when driving around in the mobile. Just about every traffic light is a noise source as well as power lines and other things that I have yet to positively identify. It's pretty bad when it even affects VHF bands. 11 meters is far worse. A far cry from the 1970's when your worst source of noise was spark plugs. Yes, it's a growing problem that I don't see going away anytime soon, SB. LED's, digital transmissions, and spark plugs can been seen as mini-spark-gap transmitters, and, unfortunately, these "things" cause massive amount of broadband RFI. If you want to see a good example of this, get an old LED calculator and hold it up right next to a AM/FM radio. In most cases (depending on the quality of the radio), the calculator will really rip up AM, and on the cheaper radios, FM will be somewhat trashed as well. Actually, this tactic can be applied to fixing your cb and ham rigs in the field. Lightly couple a pair of headphones with a capacitor, going up the audio chain until you no longer hear the LED noise. IF that happens, that's the portion of circuit where the problem lies. Very cheap audio-level signal generator . 73, Randy AB5NI
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Noise
Nov 1, 2014 11:53:09 GMT -5
Post by ab5ni on Nov 1, 2014 11:53:09 GMT -5
With all these modern noise sources there's a golden opportunity for someone with the know-how to come up with a modern filtering solution. I has been tried, MonkeyMan. They've been somewhat successful with DSP (Digital Signal Processor) chips, using something known as an FFT (Fast Fourier Transformation) to filter junk, but they haven't been extremely successful in this area. When you set your computer, CD, or other form of playback device to use different listening modes, such as music hall, auditorium, bedroom, pop, or disco, you're actually altering these waveforms "on the fly" with an FFT. Think of them as being software filters, where a filter in the hardware world would be a noise blanker circuit, with some of them working on some radios better than others. Eventually, the software dudes will come up with something that will help, and it will probably be somebody like Kenwood, Yaesu, or ICOM that eventually hits the nail on the head. 73, Randy AB5NI
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Sandbagger
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Noise
Nov 1, 2014 12:01:52 GMT -5
Post by Sandbagger on Nov 1, 2014 12:01:52 GMT -5
With all these modern noise sources there's a golden opportunity for someone with the know-how to come up with a modern filtering solution. The problem is that the noise has to be removed at the source. There is no practical way to completely filter out random wideband noise at the receiver. DSP helps, but can't completely eliminate it. The real problem is that the companies who make all the junk that generates noise aren't motivated to do anything about it. Improving shielding and bypassing all adds to the cost of manufacture. And since most of our junk is made in China, they build as cheaply as possible. The people who are affected by the noise (namely us old school analog radio operators) are not a big enough percentage of people to provide sufficient influence. The FCC has radiation specifications (Part 15), but when you have hundreds of little noise generators all over, you can't ever get away from it. And the noise is cumulative, so the more devices that are plugged in, the more the noise floor adds up. So as long as people want their digital devices and the associated networks that sustain them, us "ancient analog" hobbyists will have to deal somehow. I am surprised that I haven't heard more complaints coming from the ham community.
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Nov 1, 2014 12:40:34 GMT -5
Post by MonkeyMan on Nov 1, 2014 12:40:34 GMT -5
With all these modern noise sources there's a golden opportunity for someone with the know-how to come up with a modern filtering solution. The problem is that the noise has to be removed at the source. There is no practical way to completely filter out random wideband noise at the receiver. DSP helps, but can't completely eliminate it... So it can't be done?
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Noise
Nov 1, 2014 12:52:46 GMT -5
Post by ab5ni on Nov 1, 2014 12:52:46 GMT -5
With all these modern noise sources there's a golden opportunity for someone with the know-how to come up with a modern filtering solution. The problem is that the noise has to be removed at the source. There is no practical way to completely filter out random wideband noise at the receiver. DSP helps, but can't completely eliminate it. The real problem is that the companies who make all the junk that generates noise aren't motivated to do anything about it. Improving shielding and bypassing all adds to the cost of manufacture. And since most of our junk is made in China, they build as cheaply as possible. The people who are affected by the noise (namely us old school analog radio operators) are not a big enough percentage of people to provide sufficient influence. The FCC has radiation specifications (Part 15), but when you have hundreds of little noise generators all over, you can't ever get away from it. And the noise is cumulative, so the more devices that are plugged in, the more the noise floor adds up. So as long as people want their digital devices and the associated networks that sustain them, us "ancient analog" hobbyists will have to deal somehow. I am surprised that I haven't heard more complaints coming from the ham community. Yep. Noise floors are on the rise, for sure, SB, and I'm well aware of companies not wanting to bypass their gear for RFI, unfortunately. I guess these 10-cent parts add up in cost, especially when you're talking about making 100K units. Personally, I think the industry is missing out on a golden opportunity: what I would do is bypass all this stuff and mention on the box that this piece of electronic equipment is protected from RFI and that it has been designed to generate as little RFI as possible. To most folks, they'd be wondering what the hell all of this RFI stuff is mentioned on the box, but to folks like me and you (techies), we'd be telling our friends, " THIS is the stereo you want to purchase!!! This piece of electronics is designed correctly!!" Eventually, this "word of mouth" advertising by techies would win the day, but greed is such a major driving force these days, I very, very, very seriously doubt they'd be smart enough to consider this. "Stupid is as stupid does." You are right about us old analog dudes having to live with a lot of these problems, SB. What I do is use DSP filtering on the backend, and that tends to clean things up a bit. As far as the ham community complaining goes, we actually complained and complained around 5 years ago. Just search BPL on arrl.org, and I'm pretty sure something will pop up. Not really sure how things turned out, with the FCC being extremely corrupted by big business and their lobby groups, but I'd be willing to bet that the radio world is going to be on the receiving end of things . 73, Randy AB5NI
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Nov 1, 2014 13:14:22 GMT -5
Post by ab5ni on Nov 1, 2014 13:14:22 GMT -5
In a previous post I wrote: I should have also mentioned that it can be used in RF circuits as well. Although I've never tried this but think it would work rather well (unfortunately ), you could also use an LED lightbulb as an audio and RF source to fix radios. IF you don't have an LED lightbulb, you can always put a 1K resistor in series with an LED ground and place a bunch of these circuits in parallel, fed with a 9-volt battery, and you should hear TONS of RFI across the audio and RF spectrum. 73, Randy AB5NI
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Sandbagger
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Noise
Nov 1, 2014 13:58:41 GMT -5
Post by Sandbagger on Nov 1, 2014 13:58:41 GMT -5
The problem is that the noise has to be removed at the source. There is no practical way to completely filter out random wideband noise at the receiver. DSP helps, but can't completely eliminate it... So it can't be done? I won't go as far as to say that it CAN'T be done, but it's not something you can build a simple "Noise Blanker" circuit in hardware and remove it the way we currently do with pulse-type noise. The only possible way that I can think of to remove on-channel hash noise, would be to completely break down the receiver input signal in the digital domain, somehow identify and isolate the noise components from the desired signal components and digitally remove them, and then reconstruct the desired signal. Of course if the noise level is so high that it completely masks the signal, I'm not sure how you could do it with a wide bandwidth signal like AM or FM. But it would require high speed digital processing that would most likely exceed the cost of the radio it would be added to and it would likely distort the hell out of the signal. But if all you were concerned about is copyabilty and not rich audio fidelity, then it might be doable. Although that's above my pay grade. I was never much of a software geek.
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Sandbagger
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Noise
Nov 1, 2014 14:12:45 GMT -5
Post by Sandbagger on Nov 1, 2014 14:12:45 GMT -5
As far as the ham community complaining goes, we actually complained and complained around 5 years ago. Just search BPL on arrl.org, and I'm pretty sure something will pop up. Not really sure how things turned out, with the FCC being extremely corrupted by big business and their lobby groups, but I'd be willing to bet that the radio world is going to be on the receiving end of things . I am well aware of the fight that was put up around BPL. That was not something that would have gone over well. But the people looking to make money supplying cheap internet services over existing wiring couldn't care less about interference to a bunch of "stuck in yesteryear" hams. Unless, of course, enough high powered radio transmitters managed to disrupt their network (Interference out also means interference in). Then they'd scream bloody murder. Fortunately enough other radio services (Including commercial AM and FM) also became concerned about interference, that BPL never really got off the ground on a large scale (They do sell devices that use home wiring to network and they are really BAD for interference). Fortunately WIFI and WIMAX technology pretty much negates the need for BPL at this point. But I'm talking more about hams complaining of localized interference. When I'm using our 6 meter/220 repeater system, and the repeater drops down to half scale or lower, it can get lost in what I call "swamping zones" of noise, usually when I stop at traffic lights, or drive through certain areas of town. When I can see 1/2 to 3/4 scale signals (which don't break squelch) simultaneously on three different bands, it's pretty bad. I do know that the electric company will respond to complaints about noise generated by their equipment (insulators arc'ing etc.), but no one seems to know what to do about noise generated by other non-utility devices, especially if they are working as designed. And I fear it's only going to get worse.
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Nov 1, 2014 14:52:53 GMT -5
Post by MonkeyMan on Nov 1, 2014 14:52:53 GMT -5
I won't go as far as to say that it CAN'T be done, but it's not something you can build a simple "Noise Blanker" circuit in hardware and remove it the way we currently do with pulse-type noise. The only possible way that I can think of to remove on-channel hash noise, would be to completely break down the receiver input signal in the digital domain, somehow identify and isolate the noise components from the desired signal components and digitally remove them, and then reconstruct the desired signal. Of course if the noise level is so high that it completely masks the signal, I'm not sure how you could do it with a wide bandwidth signal like AM or FM. But it would require high speed digital processing that would most likely exceed the cost of the radio it would be added to and it would likely distort the hell out of the signal. But if all you were concerned about is copyabilty and not rich audio fidelity, then it might be doable. Although that's above my pay grade. I was never much of a software geek. Looks like MFJ is already on it... www.mfjenterprises.com/Product.php?productid=MFJ-1026www.youtube.com/results?search_query=mfj+1026
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Sandbagger
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Noise
Nov 1, 2014 15:41:13 GMT -5
Post by Sandbagger on Nov 1, 2014 15:41:13 GMT -5
I won't go as far as to say that it CAN'T be done, but it's not something you can build a simple "Noise Blanker" circuit in hardware and remove it the way we currently do with pulse-type noise. The only possible way that I can think of to remove on-channel hash noise, would be to completely break down the receiver input signal in the digital domain, somehow identify and isolate the noise components from the desired signal components and digitally remove them, and then reconstruct the desired signal. Of course if the noise level is so high that it completely masks the signal, I'm not sure how you could do it with a wide bandwidth signal like AM or FM. But it would require high speed digital processing that would most likely exceed the cost of the radio it would be added to and it would likely distort the hell out of the signal. But if all you were concerned about is copyabilty and not rich audio fidelity, then it might be doable. Although that's above my pay grade. I was never much of a software geek. Looks like MFJ is already on it... www.mfjenterprises.com/Product.php?productid=MFJ-1026www.youtube.com/results?search_query=mfj+1026This is interesting, although from the product description, it would appear to null out noise in much the same way as Pete used to null out Cousin Brucie, via antenna phasing. But I can't see how it would be that effective with only a simple built-in whip antenna, nor how effective it would be on noise that is not from a specific direction. Still and all, it might be fun to play with on a base, but it would hardly be practical in a mobile when you are constantly shifting from one noise source to another. This reminds me of another throwback story. In the 1977 time frame, I came across a guy in Norristown, who was trying to come up with a way to reduce or eliminate bleed over. Back then there were so many local channel groups that those people in-town could be within blocks of other people who ran on a different channel. I forget the guy's handle, but he was trying to build an automatic electronically phased antenna system that would null out strong signals on nearby channels, thereby reducing bleedover. The theory sounded good, but I had many operational questions (like what happens if the direction you're talking in is also the direction where the bleedover is coming from?). I'm guessing that this guy either gave up on the idea, or he could not get it to work practically. I would think something like this would have to work with an antenna like a Super Scanner, only with many more tighter nulls.
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Nov 1, 2014 16:11:18 GMT -5
Post by MonkeyMan on Nov 1, 2014 16:11:18 GMT -5
This is interesting, although from the product description, it would appear to null out noise in much the same way as Pete used to null out Cousin Brucie, via antenna phasing. But I can't see how it would be that effective with only a simple built-in whip antenna, nor how effective it would be on noise that is not from a specific direction. Still and all, it might be fun to play with on a base, but it would hardly be practical in a mobile when you are constantly shifting from one noise source to another. This reminds me of another throwback story. In the 1977 time frame, I came across a guy in Norristown, who was trying to come up with a way to reduce or eliminate bleed over. Back then there were so many local channel groups that those people in-town could be within blocks of other people who ran on a different channel. I forget the guy's handle, but he was trying to build an automatic electronically phased antenna system that would null out strong signals on nearby channels, thereby reducing bleedover. The theory sounded good, but I had many operational questions (like what happens if the direction you're talking in is also the direction where the bleedover is coming from?). I'm guessing that this guy either gave up on the idea, or he could not get it to work practically. I would think something like this would have to work with an antenna like a Super Scanner, only with many more tighter nulls. This video has a decent description of it's operation. No, probably not practical for mobile use in it's present form but maybe it could be built upon...
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Sandbagger
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Noise
Nov 1, 2014 21:05:07 GMT -5
Post by Sandbagger on Nov 1, 2014 21:05:07 GMT -5
This is interesting, although from the product description, it would appear to null out noise in much the same way as Pete used to null out Cousin Brucie, via antenna phasing. But I can't see how it would be that effective with only a simple built-in whip antenna, nor how effective it would be on noise that is not from a specific direction. Still and all, it might be fun to play with on a base, but it would hardly be practical in a mobile when you are constantly shifting from one noise source to another. This reminds me of another throwback story. In the 1977 time frame, I came across a guy in Norristown, who was trying to come up with a way to reduce or eliminate bleed over. Back then there were so many local channel groups that those people in-town could be within blocks of other people who ran on a different channel. I forget the guy's handle, but he was trying to build an automatic electronically phased antenna system that would null out strong signals on nearby channels, thereby reducing bleedover. The theory sounded good, but I had many operational questions (like what happens if the direction you're talking in is also the direction where the bleedover is coming from?). I'm guessing that this guy either gave up on the idea, or he could not get it to work practically. I would think something like this would have to work with an antenna like a Super Scanner, only with many more tighter nulls. This video has a decent description of it's operation. No, probably not practical for mobile use in it's present form but maybe it could be built upon... Hmmmm....... Honestly, it did appear to drop the sound of the noise, but the S-meter signal didn't seem to drop all that much, so I wonder how effective it really is. Still, I'd love to play around with one and see if it could null out strong bleedover stations as well as noise. I'd pay the money for one if it could do that. But I want to try before I buy. This might be something that Pete might want to try since he already has the ideal antenna setup for it.
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Nov 2, 2014 1:00:00 GMT -5
Post by ab5ni on Nov 2, 2014 1:00:00 GMT -5
As far as the ham community complaining goes, we actually complained and complained around 5 years ago. Just search BPL on arrl.org, and I'm pretty sure something will pop up. Not really sure how things turned out, with the FCC being extremely corrupted by big business and their lobby groups, but I'd be willing to bet that the radio world is going to be on the receiving end of things . I am well aware of the fight that was put up around BPL. That was not something that would have gone over well. But the people looking to make money supplying cheap internet services over existing wiring couldn't care less about interference to a bunch of "stuck in yesteryear" hams. Unless, of course, enough high powered radio transmitters managed to disrupt their network (Interference out also means interference in). Then they'd scream bloody murder. Fortunately enough other radio services (Including commercial AM and FM) also became concerned about interference, that BPL never really got off the ground on a large scale (They do sell devices that use home wiring to network and they are really BAD for interference). Fortunately WIFI and WIMAX technology pretty much negates the need for BPL at this point. But I'm talking more about hams complaining of localized interference. When I'm using our 6 meter/220 repeater system, and the repeater drops down to half scale or lower, it can get lost in what I call "swamping zones" of noise, usually when I stop at traffic lights, or drive through certain areas of town. When I can see 1/2 to 3/4 scale signals (which don't break squelch) simultaneously on three different bands, it's pretty bad. I do know that the electric company will respond to complaints about noise generated by their equipment (insulators arc'ing etc.), but no one seems to know what to do about noise generated by other non-utility devices, especially if they are working as designed. And I fear it's only going to get worse. Yeah. I remember reading about WIMAX a few years back, and I really hope that's what they've gone to in rural areas. (Too busy to keep up with this stuff.) Anywho, I guess they pretty much dropped BPL, thank God! Here are a couple of links I found on the subject: www.hamuniverse.com/rfi.html , www.arrl.org/smart-meters, and www.eham.net/ehamforum/smf/index.php?ehamsid=upecgeojkjbn71c39k08n576s1&topic=69482.0l . If I had to guess what you were picking up at red lights, I be willing to bet a dollar to a donut that the red light itself is generating all the RFI. Most of the new lights use bright LED's. 73, Randy AB5NI
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Noise
Nov 2, 2014 8:34:24 GMT -5
Post by MonkeyMan on Nov 2, 2014 8:34:24 GMT -5
Hmmmm....... Honestly, it did appear to drop the sound of the noise, but the S-meter signal didn't seem to drop all that much, so I wonder how effective it really is... Couple better examples...
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Sandbagger
Administrator/The Boss
Posts: 6,247
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Noise
Nov 2, 2014 8:49:07 GMT -5
Post by Sandbagger on Nov 2, 2014 8:49:07 GMT -5
Hmmmm....... Honestly, it did appear to drop the sound of the noise, but the S-meter signal didn't seem to drop all that much, so I wonder how effective it really is... Couple better examples... Those showed a far more dramatic reduction. I've been reading up on this thing and it is really nothing more than an antenna phasing device than can effectively null out a specific direction (where hopefully the noise is coming from). It works best if you have 2 identical antennas (Like Pete's Imaxes), or if your noise source is very close to you (like that plasma TV). I'm curious how well it would do for further knocking down adjacent channel signals beyond what I can already do with my beam, but I'm hesitant to spend $200 for an experiment that may not work out all that well..... My name isn't Gene.
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Sandbagger
Administrator/The Boss
Posts: 6,247
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Noise
Nov 2, 2014 8:53:44 GMT -5
Post by Sandbagger on Nov 2, 2014 8:53:44 GMT -5
I am well aware of the fight that was put up around BPL. That was not something that would have gone over well. But the people looking to make money supplying cheap internet services over existing wiring couldn't care less about interference to a bunch of "stuck in yesteryear" hams. Unless, of course, enough high powered radio transmitters managed to disrupt their network (Interference out also means interference in). Then they'd scream bloody murder. Fortunately enough other radio services (Including commercial AM and FM) also became concerned about interference, that BPL never really got off the ground on a large scale (They do sell devices that use home wiring to network and they are really BAD for interference). Fortunately WIFI and WIMAX technology pretty much negates the need for BPL at this point. But I'm talking more about hams complaining of localized interference. When I'm using our 6 meter/220 repeater system, and the repeater drops down to half scale or lower, it can get lost in what I call "swamping zones" of noise, usually when I stop at traffic lights, or drive through certain areas of town. When I can see 1/2 to 3/4 scale signals (which don't break squelch) simultaneously on three different bands, it's pretty bad. I do know that the electric company will respond to complaints about noise generated by their equipment (insulators arc'ing etc.), but no one seems to know what to do about noise generated by other non-utility devices, especially if they are working as designed. And I fear it's only going to get worse. Yeah. I remember reading about WIMAX a few years back, and I really hope that's what they've gone to in rural areas. (Too busy to keep up with this stuff.) Anywho, I guess they pretty much dropped BPL, thank God! Here are a couple of links I found on the subject: www.hamuniverse.com/rfi.html , www.arrl.org/smart-meters, and www.eham.net/ehamforum/smf/index.php?ehamsid=upecgeojkjbn71c39k08n576s1&topic=69482.0l . If I had to guess what you were picking up at red lights, I be willing to bet a dollar to a donut that the red light itself is generating all the RFI. Most of the new lights use bright LED's. Thanks for that link, there a wealth of information there. And I now have another potential noise source to look into, my garage door opener, which is located directly under my shack. It is the LED's but it's also the computer equipment that controls the lights. At some lights I can actually hear a shift in the sound of the noise when the light is about to change. On some of the older lights, a few unnamed CB'ers I knew could cause the lights to revert to flash mode with enough transmit power underneath them. Interference in = interference out.....
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Noise
Nov 2, 2014 10:09:27 GMT -5
Post by ab5ni on Nov 2, 2014 10:09:27 GMT -5
Thanks for that link, there a wealth of information there. And I now have another potential noise source to look into, my garage door opener, which is located directly under my shack. It is the LED's but it's also the computer equipment that controls the lights. At some lights I can actually hear a shift in the sound of the noise when the light is about to change. On some of the older lights, a few unnamed CB'ers I knew could cause the lights to revert to flash mode with enough transmit power underneath them. Interference in = interference out..... Those LED's are nasty, for sure, but I'm very surprised that the light-switching equipment is a viable source of RFI. Locally, these things are in NEMA-5 explosion-proof boxes with NEMA-5 wiring throughout, although I guess the transmission lines can age and leak RFI. All I can say is that they weren't made this way by design. Now I'm wondering if the new lights and switching equipment are using Wi-Fi to get things done? Maybe some municipalities just don't give a damn about RFI unless it's disrupting one of their local services, such as police or ambulances. (Shrug.) 73, Randy Ab5NI
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Sandbagger
Administrator/The Boss
Posts: 6,247
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Noise
Nov 2, 2014 15:40:10 GMT -5
Post by Sandbagger on Nov 2, 2014 15:40:10 GMT -5
Thanks for that link, there a wealth of information there. And I now have another potential noise source to look into, my garage door opener, which is located directly under my shack. It is the LED's but it's also the computer equipment that controls the lights. At some lights I can actually hear a shift in the sound of the noise when the light is about to change. On some of the older lights, a few unnamed CB'ers I knew could cause the lights to revert to flash mode with enough transmit power underneath them. Interference in = interference out..... Those LED's are nasty, for sure, but I'm very surprised that the light-switching equipment is a viable source of RFI. Locally, these things are in NEMA-5 explosion-proof boxes with NEMA-5 wiring throughout, although I guess the transmission lines can age and leak RFI. All I can say is that they weren't made this way by design. Now I'm wondering if the new lights and switching equipment are using Wi-Fi to get things done? Maybe some municipalities just don't give a damn about RFI unless it's disrupting one of their local services, such as police or ambulances. (Shrug.) Poor grounds and bypassing can lead to signal and power leads (and the posts themselves) becoming antennas. Most modern traffic signals have sensor leads as well as power and control. Any of which can radiate if not installed and maintained well.
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