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[Duck69]

One of the problems we face with X10 equipment is the sending and receiving of signals.
Powerline noise, phase to phase, RF interference and the like.
We end up having to buy additional pieces of the X10 puzzle and modifying some of the equipment.
Were it not for the volunteers on this forum, we would be completely lost as to where to even begin.

So, which is more important, the sending of the signal or the receiving of the signal ? Why ? How can it be accomplished ? What have you done to improve your system ?

The more information the better.

Your input and discussions will be of tremendous value to a great many of us.

Communtiy Organizers,
If you think this is a good subject; Please make it a sticky.
Also feel free to modify it.
Jim

[JimC]

Excellent post Jim and one I am sure will get some interesting responses.

My opinion for what it is worth.

You ask the question “which is more important, the sending of the signal or the receiving of the signal.” There are two types of signals involved, Power line and RF. For now I will only comment on the RF signals.

Both the transmitted signal strength and the sensitivity of the receiver are of equal importance. Both affect the range of the device. The problem is, that because of the physical size of the transmitting equipment, key chain remote, palm pads, stick a switch and motion sensors, just to name a few, it is not always possible to have the optimum antenna for transmitting the desired signal. One can modify some of these devices by adding passive antennas but aside from that little more can be done on the transmit side.

Any changes made to the internal transmitter circuits would probably be a violation of FCC regulations and should be avoided.

On the other hand it is much easier to make improvements on the receive side. Modifications can be made to the antennas of the receiving equipment. There are numerous threads discussing modifications to the antenna of the CM15A and some have reported exceptional results. One can add more sensitive receiving equipment like the V572AB. I have found that when using the V572AB I am getting range in excess of 100 feet even with a key chain remote (KR19A). Before I added the V572AB I had numerous transceivers throughout the house (RR501 and TM751) and still did not have 100% coverage.

[HA Dave]

I started with a limited system. All I had hoped for was to dim the lights in my home theater. But because my lights and equipment was in both phases of my electrical service I almost immediately starting having problems. adding a RR501  relocating the TM751 made my theater stable. But the CM11A I purchased was useless. Remote range was never a problem, I always used palmpads or the theater remote and a Infrared Mini Controller (IR543).

By the time I installed cameras, I understood the phase issue and simply planned the system to operate all on the same phase. Again the palmpad remotes and the X10 floodlights gave plenty of signal transmission.

When I decided to expand my system .... and add AHP with BXVC (through-out the house).... I had to make a new plan. I put in a passive phase coupler, the dryer plug thingy, which made the two phases function as one.

Of course the range (or lack of) of the AHP gave me fits! I copied a mod I had read about here at the forum. It was a simple mod: breaking off the top of the plastic antenna, exposing a bit of the wire inside, then soldering on a long bare wire, and taping it to the plastic stub. The fast-and-cheap mod resolved my AHP issues.

I now use one transceiver for one house code, four other codes are transceived through AHP. BOTH the transceiver and AHP are located in my basement, not generally what I would recommend, but it works well. I don't get all the range I would like from eagle and active eye motion sensors. I am sure partly, because the transceiving is done in the basement.

I use one stick-on remote, about 14 feet from the AHP.... close to it's limit in range. I use one two button remote... no range problems with it. Actually, now with BXVC, most of my remotes are in drawers. The one stick-on remote and the one two button remote trigger macros that control my microphone switching. But even those are back-ups as I use follow me commands, which trigger the macros and turn microphones on. and off.

[KDR]

I started off with the CM15A in my basement. I have an office setup down there and this is where all the computer equipment is located. I have a 2 story home and X10 on every floor.

Early on I added the V572AB in a hallway on the first floor to improve the reception of my RF stick up switches and hand held remotes. I did find that even with the V572AB that antenna position made a big difference. I was able to mount it up high above a doorway, horizontally which improved the reliability of the stick up switches. (I have those critters all over the place.)

With the hand held remotes you can somewhat direct the remote to point to the receiver. You can't do that with stick up switches and motion detectors. So with a better antenna and front end receiver that's on the V572AB everything works from everywhere.

Then I got into the security part of X10. This made the V572AB useless in this application since the V572AB won't process the RF from security remotes or keypads. So I did the antenna mod on the CM15A by adding the "F" connector to it and making a half-wave antenna. I ran about 25 feet of antenna wire up to the top of the staircase that leads down to the basement. I added 2 10 foot USB extention cables and moved the CM15A away from the computer and higher up near the ceiling in the basement. That got my security hardware working.  Been a happy camper since for the most part.

^{----------------KDR}

[gil shultz]

Sending or receiving which is more important? 

They are the same, it doesn’t matter how good the transmitter or receiver is, if they do not communicate nothing will work.  They just have to be good enough to communicate the appropriate commands.  What you are hinting at is a big problem in a lot of X-10 installations. 

The question you ask is asked many different ways but it is a very complex one.  Assuming all the equipment is operating properly we know by definition that the signal is modulated on the power line at 120 KHz at the zero crossing point.  This allows a usable signal of a few volts to be impressed on a line that has over 150V peak voltage.  These signals are filtered with tuned circuits hence there is the possibility of alignment problems but they get a much stronger signal in the pass band.  Good filters etc will give good results; poor filters will give marginal results.  Remember that these units are low priced and at best have marginal filtering abilities.

The unit putting the voltage on the power line (transmitter) can only put out a few volts.  The receiving unit (module) has a minimum sensitivity level for a valid signal.  If the signal level is below the minimum erratic or no function occurs.  Conversely if the signal is above the minimum the unit should operate properly.

Noise will swamp the front end of the receiving unit decreasing or eliminating its ability to receive and disseminate a valid signal. Noise is typically generated by an outside source.  A stronger transmitter will help or a receiver with better filters will as well.

Remember that the carrying media (power wiring) was never intended to handle low frequency RF (Radio Frequency) signals not was it designed to block them. The solution is to get enough good signals to the module so it can perform properly.  Solving this gets complicated.

Attenuation of the signal is the proper way of saying the signal level is reduced.  There will always be some attenuation of the signal in any normal system.  The trick is to minimize the attenuation or at least keep it low enough so a good signal can get through. 

There are three primary things capacitance, inductance and resistance that will attenuate the signal to a non usable level.  Expect a combination of two or three of these working in conjunction to be causing the problem.

House wiring is a source of capacitance; the effect is definitely there at 120 KHz hence line length will have an effect.  The resistance in typical power wiring will have no effect.  The inductance can depend how the wire is routed and against what. 

Power transformers are designed to operate at 50 or 60 Hz; consequently they have a high inductance which will stop the 120 KHz signal.  You see this in a typical home and add a bridge between the phases to cause the 120 KHz to go around the transformer. The advantage of this is that your signals do not pass through to other systems.

AC (Alternating Current) loads such as heaters, lights etc consume AC and do not normally interfere with 120 KHz signals.  Motors may or may not depending on there design.   On the other hand electronic equipment most by design attenuates the 120 KHz signals.  This is because the FCC (Federal Communications Commission) has placed restrictions on both conducted and radiated emissions allowed on commercial and residential equipment.  Radiated emissions go through the air while conducted emissions go through the wiring.  We are concerned with conducted emissions when working with X10.

Look at the cord that connects the video from your monitor to your computer.  There is a swelling of some type near one or both of the plugs.  This normally contains ferrite which attenuates high frequency signals.

Electronics needs DC (Direct Current) to operate internally.  This comes from a power supply of some type.  In bygone years most power supplies were built with a 60 HZ input transformer which isolated the unit from the power line (120 KHz as well). Depending on the transformer design many of these were not a problem.

Then came transformer less electronics such as TVs, these use higher frequencies which have to be isolated from the power line.  The easiest way was to attenuate them.  The attenuators were cheep but efficient and would kill a broad range of frequencies including 120 KHz signals.  These do not pay any attention to the source of the signal they just attenuated them; this is consistent across just about all power supplies.

The cost of energy has kept increasing to the point energy conservation is important.  The best way to save energy is to use less.  The original power supplies at best could get an efficiency of 50%.  The transformer less designs was approaching the 70% efficiency range. This is not good enough today so the switch mode power supplies have become popular.  These are typically better then 95% efficient.  These use high frequency designs and power MOSFETs (Metal Oxide Semiconductor Field Effects Transistor).  The MOSFETs can switch in the Megahertz range, and generate lots of high frequency noise.  Consequently the line attenuators are much better and also attenuate the 120 KHz even more.
 
I have posted the bulk of this before but it is still valid.
This is a short and simple explanation of what your asking. This can and sometimes does get much more complicated then what I have covered her.

Good Luck
Gil Shultz