UPLC "sets record straight" on BPL

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (ke4pjw @ June 28 2004,15:41)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (n1ir @ June 27 2004,06:27)</td></tr><tr><td id="QUOTE">1)Please look up 'deterministic'. It's either signal or noise, Ed. Which is it?[/QUOTE]<span id='postcolor'>
<a href="http://users.ece.gatech.edu/~mleach/ece6416/noisepot/chap01.pdf" target="_blank">
Noise is any unwanted signal that interferes with a desired signal. Most electrical noise can be categorized as being either random or deterministic. </a>[/QUOTE]<span id='postcolor'>
Would you be so kind as to point out this definition's citation? Please, a technical reference, preferably one with a physics base.

Many thanks,

73,
Chip N1IR

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (K7JAZ @ June 28 2004,14:44)</td></tr><tr><td id="QUOTE">First of all, as to the remark by W1RFI,... since when does the person  who says "it can be done" have to be the one to do it, or not have the right to speak?  Not everyone who has the ability to foresee something has the technical ability to do it themselves, is that wrong?  Do you have the technical knowledge and experience to research and design better computers, radios, transmitters, modulation modes, etc.?  No?  There are plenty of hams who don't, and plenty who do. The idea that you don't have the right to suggest an improvement or research into anything technical without doing it yourself is insulting not to mention just plain stupid!

President Kennedy said we'd put a man on the moon, but he didn't do it himself, did he?

For the rest of the pessimists, OK, it can't be done.  The End.  Ham radio is doomed.

We all may as well just put our HF radios in the storage shed and go to VHF, UHF or Echolink until the big power companies feel it's time to have mercy on us and develop a filter for us, which may never happen, eh?  Is that pretty much what you guys are saying?  If not, then what are you saying?

Jim
XE1/K7JAZ[/QUOTE]<span id='postcolor'>
Hi Jim,

I'm excited about the future of ham radio. Ultimately it will embrace new technologies rather than attempt to kill them (at least in actions by some).

The second we cooperate to solve problems, the sooner we will benefit towards the solution to any BPL problems of our ham colleagues.

I am convinced of this

73,
Chip N1IR

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (n1ir @ June 27 2004,17:05)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (ke4pjw @ June 28 2004,15:41)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (n1ir @ June 27 2004,06:27)</td></tr><tr><td id="QUOTE">1)Please look up 'deterministic'. It's either signal or noise, Ed. Which is it?[/QUOTE]<span id='postcolor'>
<a href="http://users.ece.gatech.edu/~mleach/ece6416/noisepot/chap01.pdf" target="_blank">
Noise is any unwanted signal that interferes with a desired signal. Most electrical noise can be categorized as being either random or deterministic. </a>[/QUOTE]<span id='postcolor'>
Would you be so kind as to point out this definition's citation? Please, a technical reference, preferably one with a physics base.

Many thanks,

73,
Chip N1IR[/QUOTE]<span id='postcolor'>
If you did not follow the link, please do so. The paper was authored by W. Marshall Leach Jr., Professor, Georgia Institute of Technology. Please click on that link to see his credentials.

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (ke4pjw @ June 28 2004,16:40)</td></tr><tr><td id="QUOTE">If you did not follow the link, please do so. The paper was authored by W. Marshall Leach Jr., Professor, Georgia Institute of Technology. Please click on that link to see his credentials.[/QUOTE]<span id='postcolor'>
My apologies; I lacked precision in my request.

This is not a primary citation; my point is that being a professor does not necesarily lead to infallibility. Could you pass along one (of many) possible primary citations? It is my recollection that the definition of signals and noise invoke information or lack of it.

Care must be taken to distinguish the difference between interfering SIGNALS and bona fide NOISE.

I would be delighted to pass along some citations of a primary nature for your edification if you need it. I have taught signals and systems in a telecom program, BTW. I am a retired professor.

I do not yet have the pleasure of knowing your handle. I am pleased that you now recognize mine. Kindly pass your along.

73,
Chip N1IR

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (n1ir @ June 27 2004,18:46)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (ke4pjw @ June 28 2004,16:40)</td></tr><tr><td id="QUOTE">If you did not follow the link, please do so. The paper was authored by W. Marshall Leach Jr., Professor, Georgia Institute of Technology. Please click on that link to see his credentials.[/QUOTE]<span id='postcolor'>
My apologies; I lacked precision in my request.

This is not a primary citation; my point is that being a professor does not necesarily lead to infallibility.  Could you pass along one (of many) possible primary citations? It is my recollection that the definition of signals and noise invoke information or lack of it.

Care must be taken to distinguish the difference between interfering SIGNALS and bona fide NOISE.

I would be delighted to pass along some citations of a primary nature for your edification if you need it. I have taught signals and systems in a telecom program, BTW. I am a retired professor.

I do not yet have the pleasure of knowing your handle. I am pleased that you now recognize mine. Kindly pass your along.

73,
Chip N1IR[/QUOTE]<span id='postcolor'>
I am using the term noise within the context of the following definition.

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE"> An undesired disturbance within the frequency band of interest; the summation of unwanted or disturbing energy introduced into a communications system from man-made and natural sources. [/QUOTE]<span id='postcolor'>

You seem to be under the impression that because the BPL systems will be radiating a signal, that it is somehow not noise.

The information the SWLs, ham or aircraft radio is attempting to detect is the "Signal". The signals that reside within the bandpass of the radio, being radiated by the BPL injectors, modems and other sources, are "Noise".

Is my argument so weak and/or understanding of interference so vacuous that you don't care to debate at my lowly level?

Actually, I found typos in two of my posts. When I went to correct your name, I saw that you had all ready commented on it, so I did not edit the post. My name is Terry, BTW.

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (n1ir @ June 27 2004,16:36)</td></tr><tr><td id="QUOTE">We don't need 70 dB of dynamic range and the AGC on SSB ham receivers doesn't deliver 70 dB of dynamic range. They say they do but in practice they don't.  An AGC circuit is a compression that limits the dynamic range. This is not a difficult problem for a 20-25 dB dynamic range BTW. The problem is that there is no business case for it. Hams are the only ones who might need such removal with SSB these days. Didn't SGC have a nice system that was totally ignored by hams? Feel free to refresh my memory properly.

You might also refresh me , or correct me, on some other points of fact. For example, didn't the ARRL lose 15-20% of membership in the last few years? Aren't ad pages   down in QST? If so, and again I invite your correction on these statements,  I interpret this as  barometer of a declining base of active HF hams, and thus a tough sell in a business case.

If I was in need of an opportunity, and devoid of ideas, your suggestion would be helpful. However, the world today is full of marvelous offering memoranda from other parties  and my preference these days is to review bioscience ones from them--at my invitation.

As a younger man, seeking my fortune, your advice may have been pertinent. What a pleasure to have acquired some degree of comfort and wisdom along the way I'm sure you know what I mean.[/QUOTE]<span id='postcolor'>
All fine and good, Chip, but just what does this have to do with the filtering techniques to remove 70 dB of interfering signal on a communications channel?

Could you at least post a block diagram or a flow chart of the techniques that could do that? Or are you another one of those that says it can be done, but doesn't know just how?

Don't you think that if it could be done, we would be using those techniques right now to copy signals that are 70 dB below the present man-made noise levels?

Ed

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (n1ir @ June 27 2004,17:10)</td></tr><tr><td id="QUOTE">The second we cooperate to solve problems, the sooner we will benefit towards the solution to any BPL problems of our ham colleagues.[/QUOTE]<span id='postcolor'>
You imply that you have the knowledge about these things, Chip. So let's start that with you and post the block diagram or flow chart that explains how to remove 70 dB of man-made noise from a communications channel.

Or is this one of those do as you say, not do as you do sort of things?

Ed

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (W1RFI @ June 29 2004,00:20)</td></tr><tr><td id="QUOTE">"Don't you think that if it could be done, we would be using those techniques right now..."

"Could you at least post a block diagram or a flow chart of the techniques that could do that?  Or are you  another one of those that says it can be done, but doesn't know just how?"

"Or is this one of those do as you say, not do as you do sort of things?"


Ed[/QUOTE]<span id='postcolor'>
Well now I'm really amazed.  The head of the ARRL Lab says "if it could be done, we'd be doing it".  

We didn't come by our present technology all at once.

All I've been trying to say is, just because we have a million and one reasons why it can't be done today doesn't mean it's impossible and won't be done one day soon.   I can't believe this is such an abstract idea and so hard for some to swallow, and getting the snide comments as in the above quote.  


Edited by K7JAZ  

 

K7JAZ,

It is time you left. The Iowa BPL test that was under the gun for interference closed out early. Interference was one of the reasons.

 

K7JAZ,
Jim I think you are alittle bit out of line,if I may be so bold to say so.Even though you only started in Amateur Radio in the 70's,you have been around Technology long enough to know the pace the state of the Art can move.
As ARRL because of the stunt they pulled against the members without even consulting them,they are not on my Xmas Card list.As to Ed Hare he and I have exchanged difference of opinons on several occasions,HOWEVER the ARRL supplies him with some of the most up to date testing facilities and ED has the expertise amongst he and his peers to use that equipment.I only wish my humble facility were as proper as theirs.Your experience in Technical surroundings I'm sure has shown that one must stay up on the current state of the Art to function properly.What Ed has plainly tried to explain is that at present there is no way to discern a signal buried in 70 dB of noise(predictable and random sources ).Some of the data modes due a vey good job of reaching into the noise for a signal,nothing in the order of 70dB. Spread Sprectum gives you a little better than 20dB gain in signal to noise,but still short of the goal.Until you have the ability to separate the signal from the noise ,you can't reliably even measure the s/n ratio to say how good or bad it is.
There are still a few very sharp Amateurs around who with the proper facilities and time and finances could make improvements to the exsisting state of the ART.However I would not count on the present crop of non-technical diddle and fiddle technicians to become Einstiens over night.It is also obvious the BPL industries are not going to fund technical studies to solve a problem that so far does not cause them distraction.

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (ke4pjw @ June 28 2004,19:16)</td></tr><tr><td id="QUOTE">I am using the term noise within the context of the following definition.

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE"> An undesired disturbance within the frequency band of interest; the summation of unwanted or disturbing energy introduced into a communications system from man-made and natural sources. [/QUOTE]<span id='postcolor'>

You seem to be under the impression that because the BPL systems will be radiating a signal, that it is somehow not noise.

The information the SWLs, ham or aircraft radio is attempting to detect is the "Signal". The signals that reside within the bandpass of the radio, being radiated by the BPL injectors, modems and other sources, are "Noise".

Is my argument so weak and/or understanding of interference so vacuous that you don't care to debate at my lowly level?

Actually, I found typos in two of my posts. When I went to correct your name, I saw that you had all ready commented on it, so I did not edit the post. My name is Terry, BTW.[/QUOTE]<span id='postcolor'>
Hi Terry,

It is a quagmire. I now understand some of the misconceptions about 'signals' and 'noise' here.

Going back to fundamentals, from Leo Szilard in the 1930's, the distinguishing characteristic between 'signal' and 'noise' is information. If you request, I will post the original Szilard citation.

There are two classes of 'signal' in our context: wanted signal and interfering signal. Both are information bearing.

Noise is not information bearing.

Interfering signals are deterministic in the sense that they are produced in a defined way with fidelity. Thus if there exists knowledge of what they are and the effects of the medium in their propagation, they can be removed in the detection process. The accuracy with which this knowledge is known helps detemine the dynamic range that can be sought in the removal.

Ed Hare appears to want my exchange to wander to a non-rational level, which I shall not indulge.

I would like to ask a pertinent question to this thread though: from 2-80 MHz, what does the power spectrum of BPL look like at the antenna of a fixed station? Two or three snapshots could be most interesting.

A power spectrum is not a be-all of interfering signal removal, but is an excellent 'first look' diagnostic. I'm certain that power spectra of BPL signals exist; if not from ham measurements than from NTIA. Are they available on the web? Anyone?


73,
Chip N1IR

 

Noise as defined by IEEE Standard Dictionary and generally accepted to be "NOISE" when talking about Radio reception is separted by 2 general catagories, one being Predictable noise,that of a synchronous signal and Random Noise that having no predictability and nonsynchronous in nature.
An undesired disturbance within the useful frequency band may be called noise. note:Undesired disturbances within the useful frequency band produced by other services may be called interference.

Douglas-Young Encyclopedic Dictionary of Electronics,
Noise: Random unpredictable and undisirable signals,or changes in signals,that mask desired information content.Noise in Radio transmission is called static,or atmospherics,and in television is called snow or confetti from it's appearance on the TV screen.
--------------------------------------------------------------------
Signals generated by BPL that appear in the bandpass of a communications reciever that mask or render the desired signals non-decipherable is considered unwanted noise.Noise that mask's the desired signal by 70 dB is considered UNWANTED NOISE.........

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (n1ir @ June 29 2004,04:57)</td></tr><tr><td id="QUOTE">I would like to ask a pertinent question to this thread though: from 2-80 MHz, what does the power spectrum of BPL look like at the antenna of a fixed station? Two or three snapshots could be most interesting.

A power spectrum is not a be-all of interfering signal removal, but is an excellent 'first look' diagnostic. I'm certain that power spectra of BPL signals exist; if not from ham measurements than from NTIA. Are they available on the web? Anyone?

 
73,
Chip N1IR[/QUOTE]<span id='postcolor'>
Chip,

I can't provide exact URLs but in reading some of the reply comments on the FCC Web Site, particluarly those with attachments, one or more of them included shots of what a BPL signal looked like on a Spectrum Analyzer. There may even be some in the ARRL reply comments. These do not cover the full spectrum used by the BPL signal but are limited by the bandwidth of the analyzer used.  From memory the signals show up as a series of peaks spaced 1.1KHz apart througout the passband with modulation superimposed upon them, at least for one type of BPL modulation scheme.

Now a question:  If an interfering and desired signal with differing modulation characteristics are both on the same frequency and the interfering signal is 50-70dB stronger than the desired signal and the modulation characteristics are sufficiently well known and do not vary significantly over short periods of time, could the desired signal be recovered?

73,
Mike WA3KYY

 

Here's my new wireless internet access system! It operates on 28 channels in the 800 MHz band.
(yes, the same 28 channels that the police and fire departments use - but at Part 15 power levels.)
It has great interference mitigation equipment. As soon as I receive a complaint from the public service agencies, alleging interference from my system, I'll investigate to see if it is really my equipment doing the interfering. If I confirm that my equipment is at fault, the entire system can quickly respond by moving to another of the 28 channels. After all, police cars are mobile, and if they get
interference in one spot, they can always move to another spot. One great advantage is that 800MHz transmissions don't propagate worldwide on just milliwatts, like HF signals do.

 

In your comments to the FCC, you might mention that there are a lot of services, not just amateurs, who will be impacted. The California Highway Patrol, for one, operates in the 42 MHz range.

That band is also particularly popular with rural counties, particularly large, mountainous ones, because of the lower frequencies' ability to "go around mountains." These are the areas with the least financial resources. They may well be forced to switch to higher - frequency systems, with the added costs of repeaters, etc. And these are exactly the areas that BPL is supposed to help. How helpful is it to wipe out the radio equipment of your local volunteer fire department? How many pancake breakfasts are YOU willing to attend to pay for all that new radio equipment, and the ongoing expense of maintaining repeaters?

Also, U.S. military tactical radios utilize the 30 to 70 MHz range, at very low power levels. I "attended" the Los Angeles riots with my National Guard unit. While phone service was not disrupted too badly, we didn't have phones where we had to operate. We were dependent on our radios. Had BPL been in use in Los Angeles, our military radios would have been useless. Or conversly, BPL would have to have been shut down. Given the important role now played by computers in keeping people informed, shutting down any ISP would have been insanely stupid. In short, they wouldn't have done it. Therefore, we wouldn't have had communication with our personnel in the field. How stupid is that?

As the services are driven out of the "low VHF" public service band, it will increase overcrowding in the remaining bands. Another bad.

Also, I heard on the news yesterday, I think, of a new satellite - based internet linking system that is also supposed to bring the internet to any place on earth. So where's the "need?"
KA6GJN