Though this was developed long before PLC - never-the-less -Power Line Communications products, as you should know, run well above the audio range -some I have been told are at 20-30Mhz. This filter is for home audio use and so I made it only cover the audio range above power line freq. It is low Z/short up to 20KHz only. Your spirited comments are not informed as to the app here.
[Note: Its easy to inject signals into the ac line and measure z and atten at audio freqs. when filter applied] - Thx, RNM
My newer filter designs also address the PLC issue and work completely differently and include outlet to outlet isolation of >100dB on the top model. I also use the new filters with PLC in my home to watch streaming Netflix in HD from one room to another.
JC ?? what was it you wanted to know?
The 'nominal' 100 Ohms is a useful number to illustrate how the filter works. Geeez - still so word literal and picky while the point is not being addressed. This isnt a Tice clock. Any signals on the line between about 200Hz and 20KHz will be attenuated and wont work well.
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Well Richard, I worked with Jack Bybee, about 17 years ago on a combination lightning arrestor and AC purifier. Haven't made one in years, but I use one in my own system. You would like Jack Bybee, he has this modified Bentley that gives him 651 HP. (He used to own a chip company). It's a nice car, best 'back seat' I have sat in for years. Are you going to the Audio Show in August?
I'm glad I am not the only one who has tripped over Dick's loose affiliation with the meanings of words! At audio frequencies a length of mains cable has a strongly frequency-dependent characteristic impedance (like almost any other cable), which will be nothing like a resistance. At lower frequencies, where the resistance dominates over inductance, propagation could be more like diffusion than waves.RNMarsh said:
However, the characteristic impedance at RF frequencies (which could be around 100 ohms) does at least allow you to estimate the inductance and capacitance of the cable so you can use these in a lumped model for audio frequencies.
I'm afraid I did not see the statement you quoted. It is incorrect of course, as you understand.
When I first heard about the tice clock, I completely dismissed it as absurd.
Your information is new to me, I had not considered line filtering.
Was it hot to neutral only, or was there a hot to ground component as well?
jn
Well no, http://www.urel.feec.vutbr.cz/ra2007/archive/ra2002/pdf/41.pdf.
Powerline communications with reserved bands as low as 3K are common (EN50065-1 power line communication standard). There is also X10.
I admit I don't know the current status of the proposed "smart grid" but the power companies have reserved the low band 3K-95K. It is concievable that some day in the future BB will want to control your AC, hot water, etc. for peak and off peak use with smart appliances. I which case local jurisdictions will probably make blocking these signals a crime punishable by fines and imprisonment.
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I think you under estimate the Ls of the long ac wiring.
It is not loosness but rather incompleteness of the email -- the use of 100 Ohms or 50 or 75 Ohms is because the patent does not limit the use of the design only to audio freq apps. It could just as well be implimented with sm devices at any freq for a different app. The connection with the ac wiring cable Z of 100 ohms and the use for audio apps in the same email paragraph, i admit was confusing.
This is still a tangent to the long winded input on how trying to measure something originally thought to be audible can give unexpected results and lead to other areas of pursuit and inquiry.
JC -- I dont care if you show with MIT. I havent talked to them in over a decade. It is my invention that I gave away to them to have and use. There's no money in it for me... too low volume. And, i dont want to be in the mfring business, myself. It was a fun discovery that lead to something new for me. btw -I'm selling my 700 Hp ZR1 for a Bentley... nice and slow and heavy as a tank. Sure, that's what i want. Not sure about that car event a.t.t. -RNM
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I doubt that it would work with X10. And, smart grid controls offer an interesting possible limit on its use. By then we'll all be self powered via solar
-RNM
After PG&E installed their smart power counter on a wall of my garage I had to remove a light with movement sensor. It started flashing periodically.
PLC is adding EMC to the power lines, not good in a lot of peoples opinions, including Keith Armstrong (UK based EMC expert), so we are going to have to think about filtering this rubish fromthe lines, never mind the magnetic loops formed by your house wiring that could couple it into all sorts of equipement. Radio Hams dont like it at all!!!
If you assume for a moment that what people percieve could be true... you can usually find a serious and measurable reason for it. but if you dismiss it... you wont find or learn anything, of course. This is one of my points here.
Hot to N only. This info here is the first time I have ever mentioned it to anyone before.
If you have the luck to afford it in a new home, use the industrial method of wiring and put it all in EMT (metal tubing).
The Ham bands have been removed from the bands used by PLC (that was a fight from 8-10 years ago) As I understood it the stuff below 100KHz is not used domestically, but rather on the long distance transmission lines. Echelon runs in the 100-500K band as I recall. I think the other control guys are in that band. Intellon and the other high data rate guys use the 2-30 MHz band. there is too much loss above 30 MHz to get much use. The Intellon chip can dump several amps at 20 MHz into the line. X10 is low frequency. Its bursts around the zero crossing so it has a broad interference band. The usual filter on a switch mode supply will kill any of these signals pretty effectively. Most people have more than a few of these in their homes today.
Power wiring was not designed to be a transmission line but if you need to deal with it calling it a 100 Ohm line is as useful as anything. The Mil standard for testing AC line filters uses a 50 Ohm source simply because a better model for power wiring doesn't exist and you need something.
Power wiring was not designed to be a transmission line but if you need to deal with it calling it a 100 Ohm line is as useful as anything. The Mil standard for testing AC line filters uses a 50 Ohm source simply because a better model for power wiring doesn't exist and you need something.
This is only half true. This company offers Broadband Powerline Modems, and the power companies of Zurich and Mannheim are already using such devices on the low voltage (i.e. 230/400V) grid for communication between the counters and the transformer station, (at least in Zurich it's only a pilot, but nevertheless).
Frequencies are way in the MHz.
Echelon, AMIS (Siemens), Landis&Gyr et al are in the Cenelec A Band, i.e. 3-95 kHz
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Tangents -
Demian and I and Tony DiChiro have been involved together in this a long time. We have filters which are compatible with PLC, X10 et al.
As a detail of no consequence - the ac power line Z in usa is closer to Z=100 ohms. The standard Z to measure emi/rfi et al on the ac line or ac line filters uses Z of test equipment used for the purpose (50 Ohms). 100 Ohms isnt a standard Z in test & measurement equipment.
Thx,
Richard
Demian and I and Tony DiChiro have been involved together in this a long time. We have filters which are compatible with PLC, X10 et al.
As a detail of no consequence - the ac power line Z in usa is closer to Z=100 ohms. The standard Z to measure emi/rfi et al on the ac line or ac line filters uses Z of test equipment used for the purpose (50 Ohms). 100 Ohms isnt a standard Z in test & measurement equipment.
Thx,
Richard
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