X10 Community Forum

🔌General Home Automation => Automating Your House => Topic started by: bkenobi on December 17, 2012, 10:53:14 AM

Title: X10 RF on a cable TV run?
Post by: bkenobi on December 17, 2012, 10:53:14 AM
I have my CM15A in the office.  I do not get enough coverage with it's antenna, so I converted it to coax and installed a Radio Shack antenna in the attic.  I have a single run of coax from the structured media box to the office and a couple to the attic, so I used that pair to link the antenna to the CM15A.  I was getting a lower than desired boost in signal strength, so I added an amplifier to the run and everything works wonderfully!

Up until now, I've been a DirecTV user.  I don't have a TV in the office that's hooked up since I didn't want to pay for a receiver that's never used.  So, using the coax run hasn't been an issue.  I wanted cable TV when we bought the house, but it wasn't run out our way.  Yesterday I found out that a new cable TV company has just extended service to our area and perhaps even across the street, so I'm almost certainly going to switch.

SO...  According to the sales rep I spoke to, the service they provide includes: Digital cable, analog cable, cable internet, phone.  My question is about using the same line for running my X10 RF antenna on the same line as the digital/analog cable/internet.  As far as I know, X10 is in the 310MHz range.  According to Wikipedia, there might be interference on channels 38 or 39 if the frequency range is still used.

http://en.wikipedia.org/wiki/North_American_cable_television_frequencies

It wouldn't be exceptionally difficult to install a new cable run from the office to the structured media box.  It also might be possible to move the CM15A to the same area as the structured media box and use a USB->ethernet adapter (already have one and 1 unused connector in the office but never tested how the unit works).  Anyone know if I will have interference on either TV or CM15A if I just use a signal combiner?  What about potential damage using a signal amplifier?
Title: Re: X10 RF on a cable TV run?
Post by: Dan Lawrence on December 17, 2012, 11:15:20 AM
Who is the cable provider?   That may make the difference.  I've had X10 before the cable company wired Baltimore City, no interference to x10 at any time.   Now the cable provider is Comcast, no problems arose.   
Title: Re: X10 RF on a cable TV run?
Post by: bkenobi on December 17, 2012, 11:42:31 AM
The company is called Wave Broadband.  I don't know anything about them since they are new to the area.  We've had Comcast in the past, but that was at our last house when we only had 1 light hooked up to X10 and used a firecracker/TM751 as the extent of our setup.

http://www.wavebroadband.com/
Title: Re: X10 RF on a cable TV run?
Post by: dhouston on December 17, 2012, 11:45:58 AM
If I understand correctly your current setup has an antenna in the attic that feeds a coax to the media box where another coax feeds it to your office. You want the cable from the media box to office to carry both TV and X10 RF.

Other than signal losses from using two combiner/splitter devices, you should be OK. Any interference should be limited to 1-2 channels and that only when sending X10 RF.
Title: Re: X10 RF on a cable TV run?
Post by: bkenobi on December 17, 2012, 11:58:35 AM
Yes, that is exactly what I'm suggesting. Interference when x10 rf is received is perfectly acceptable for this setup, so i think its worth giving it a try. Thanks for the input!
Title: Re: X10 RF on a cable TV run?
Post by: Noam on December 17, 2012, 12:36:08 PM
Who is the cable provider?   That may make the difference.  I've had X10 before the cable company wired Baltimore City, no interference to x10 at any time.   Now the cable provider is Comcast, no problems arose.   
Dan -
I don't think the OP is concerned with interference between the cable TV signal and the PLC signals. It sounds like the OP is trying to use a single Coax cable to carry BOTH the cable signal AND the extended CM15A antenna signal. That sounds like a totally different scenario than the one your described.
Title: Re: X10 RF on a cable TV run?
Post by: Noam on December 17, 2012, 12:44:37 PM
... It also might be possible to move the CM15A to the same area as the structured media box and use a USB->ethernet adapter (already have one and 1 unused connector in the office but never tested how the unit works). 

I had a LOT of trouble a few years ago when I tried a USB-over-CAT5 adapter (essentially a USB extension, using CAT5 in between the two halves). The CAT5 cable was picking up a lot of electrical noise from random stuff in my house, and that interrupted the USB signal, causing the CM15A to re-initialize the connection. After too many re-inits in a short window, the CM15A went into an "error" mode, and needed to be restarted. I worked with two engineers from the AHP team at X10, and together we concluded that the usb-over-CAT5 extenders weren't providing the uninterrupted USB connection that I needed. I tried a number of them, and had similarly bad results.
I also tried a USB-to-network host, which plugs into my network, and provides a USB port that can be mapped to any PC on the network (using a driver and TSR on the PC). The problem with the one I tried was that there was no way to auto-start the virtual port. You needed to log into the PC, open the utility, and then "connect" the port. That was a deal-breaker for me, as the system wouldn't work after a reboot until I did that.

In the end, I just used a long (around 75-foot) extension cord to move the CM15A closer to the PC, but still plug it into the front of my XTB-IIR booster in the other room.
Title: Re: X10 RF on a cable TV run?
Post by: dave w on December 17, 2012, 01:00:59 PM
Yes, that is exactly what I'm suggesting. Interference when x10 rf is received is perfectly acceptable for this setup, so i think its worth giving it a try. Thanks for the input!
$0.02
I think the sound subcarrier for channel 38 will be your biggest problem, but I think Dave Houston's concern about combiner / splitter losses will be the major road block.
Title: Re: X10 RF on a cable TV run?
Post by: Brian H on December 17, 2012, 01:02:35 PM
If your cable company is using the Hypeband channel 38. There will be a very strong signal always on the X10 310 MHz and you may receive nothing from your X10 extended antenna. If it is strong enough, it may overload the CM15As receiver.
Also if you have any Digital Decoders. Make sure the coupler splitter is rated to pass the reverse channel data back to their head end.
When I added my own cable runs in my home. I used splitter couplers rated for Cable TV use with a back channel passage.
Even my amplified cable amp has a back channel rating.
Title: Re: X10 RF on a cable TV run?
Post by: bkenobi on December 17, 2012, 01:38:33 PM
Sounds like the usb to ethernet adapter is out then.  I didn't think about the possibility of the cable breaking the x10 signal, but that's definitely  a possibility now that i think about it.  The new run is only 15 feet through a crawl space, so I should probably just go that route. The only reason i was trying to avoid it is dealing with the insulated wall and having to go into that crawl space.  Meh, it's sounding more like a choice between that or not having cable in that room.  I guess neither is a huge deal.
Title: Re: X10 RF on a cable TV run?
Post by: dhouston on December 17, 2012, 01:53:09 PM
If you already have the combiner/splitter devices, it may be worth a try. I assume the amplifier will be between the antenna and first combiner/splitter. You may have enough signal strength to counter the cable signal - it will need to be stronger than the cable signal for the CM15A RF receiver to dig it out of the combined signal.

Would it be possible to use the existing cable as a pull-wire to install two new cables? That keeps you out of the crawl space.
Title: Re: X10 RF on a cable TV run?
Post by: bkenobi on December 17, 2012, 02:51:59 PM
Hadn't considered using the cable as a pull.  That's an option depending on if they stapled it down.  We have a mostly full basement, but there are 2 rooms that were left as crawl spaces.  It's not a huge ordeal to go in them, but obviously they are still crawl spaces and never fun.  My last house had one that was between 2 and 5 feet deep, so it was pretty manageable to get around.  I haven't been in this crawl space yet, but the other one was quite tight (closer to 18" at it's highest).  I'll probably take a look in there to see how bad it would be to work in.
Title: Re: X10 RF on a cable TV run?
Post by: dhouston on December 17, 2012, 03:02:36 PM
About 50 years ago, I spent about two years installing commercial sound systems (office buildings, banks, bars, restaurants, supermarkets, malls, etc.) in the San Francisco area. I saw a lot of crawl spaces, including one above a dropped ceiling in the North Beach area that I thought might become my last residence - but I finally wriggled out of it. Rats like to gnaw on electrical wire and they had chewed through several speaker wires.
Title: Re: X10 RF on a cable TV run?
Post by: bkenobi on December 17, 2012, 03:10:00 PM
I've been in a handful of attics and crawl spaces, but never as a job.  I can say that I've learned enough in that short time to know that they are not where I want to make a living!  They really show what kind of shape a person is in.
Title: Re: X10 RF on a cable TV run?
Post by: frank on June 01, 2013, 01:18:11 PM
In the end, I just used a long (around 75-foot) extension cord to move the CM15A closer to the PC, but still plug it into the front of my XTB-IIR booster in the other room.

Sounds like reliable way to 'place' the cm15a near the distribution point.  I had been planning to buy a pair of usb-over-Ethernet extenders until I read your post.

I'm thinking of running about 80' or so of 14-2 from an outlet near the pc to a breaker in the breaker box to achieve what you did with the extension cord.  I will just pick up one side of the 220.
 
Do you still consider this the most reliable way to 'centralize' the cm15a when the PC is remote from that location?

Thanks,
Frank
Title: Re: X10 RF on a cable TV run?
Post by: Noam on June 02, 2013, 05:44:02 PM
In the end, I just used a long (around 75-foot) extension cord to move the CM15A closer to the PC, but still plug it into the front of my XTB-IIR booster in the other room.

Sounds like reliable way to 'place' the cm15a near the distribution point.  I had been planning to buy a pair of usb-over-Ethernet extenders until I read your post.

I'm thinking of running about 80' or so of 14-2 from an outlet near the pc to a breaker in the breaker box to achieve what you did with the extension cord.  I will just pick up one side of the 220.
 
Do you still consider this the most reliable way to 'centralize' the cm15a when the PC is remote from that location?

Thanks,
Frank

You're likely to have fewer problems extending the CM15A's power connection than you will trying to extend the USB connection. But three are no guarantees.
Title: Re: X10 RF on a cable TV run?
Post by: frank on June 02, 2013, 06:50:13 PM
Quote
You're likely to have fewer problems extending the CM15A's power connection than you will trying to extend the USB connection. But three are no guarantees.

Thanks.  That is what I was thinking as well.  I am glad I didn't buy the extenders.
Title: Re: X10 RF on a cable TV run?
Post by: JeffVolp on June 03, 2013, 12:43:57 AM

Just remember there will be some signal loss in that AC power run to the distribution panel.

Jeff
Title: Re: X10 RF on a cable TV run?
Post by: frank on June 03, 2013, 07:48:53 AM
Thanks Jeff.  The limited advantage of a direct AC run is that it, in effect, bypasses the some 25 to 30 ea. 120 vac devices that are currently plugged into the same place, from which the cm15a is powered.  And that AC run goes around walls and such spliced at several outlets on its way to the breaker box.

I figure this will at least give the cm15a signal a fighting chance.  Not sure what else to do to improve the signal.

I don't have a way to measure the X10 signal strength.  That would be a nice tool to have.
Title: Re: X10 RF on a cable TV run?
Post by: JeffVolp on June 03, 2013, 09:11:50 AM

Out of curiosity, I just checked this myself.  I plugged an old Maxi Controller into a 50 foot length of 16 gauge extension cord stretched out straight to simulate a long wire run.  I removed my XTBR, and checked signal levels with my XTBM-Pro prototype.  The readings were 9.59Vpp at the Maxi Controller, and 2.57Vpp at the outlet adjacent to the distribution panel where the extension cord was plugged in.  So almost 3/4 of the signal level was lost in that run.

Jeff
Title: Re: X10 RF on a cable TV run?
Post by: Brian H on June 03, 2013, 09:11:58 AM
Frank, Do you presently have a phase coupler or coupler/repeater between the phases?
XTB-IIR is the gold standard one. My lowest signal is about 1.5 volt as measured by a XTBM test meter. With my XTB-IIR installed.

Have you done any X10 troubleshooting. To remove a signal sucker or noise maker.

http://jvde.us/x10_troubleshooting.htm
http://www.act-remote.com/PCC/uncle.htm
http://www.davehouston.net/
Title: Re: X10 RF on a cable TV run?
Post by: frank on June 03, 2013, 09:48:27 AM

Out of curiosity, I just checked this myself.  I plugged an old Maxi Controller into a 50 foot length of 16 gauge extension cord stretched out straight to simulate a long wire run.  I removed my XTBR, and checked signal levels with my XTBM-Pro prototype.  The readings were 9.59Vpp at the Maxi Controller, and 2.57Vpp at the outlet adjacent to the distribution panel where the extension cord was plugged in.  So almost 3/4 of the signal level was lost in that run.

Jeff

Incredible!  I never would have expected that much loss in such a short & not otherwise loaded length of wire.
Title: Re: X10 RF on a cable TV run?
Post by: JeffVolp on June 03, 2013, 10:08:00 AM

It makes sense.  The distribution panel is the common junction for all the signal loading in the home.  With the distributed inductance over the length of the extension cord, it begins to look like a low-pass filter that attenuates the 120KHz X10 signal.

This is the reason I recommend locating a repeater adjacent to the distribution panel rather than at a dryer outlet.

Jeff
Title: Re: X10 RF on a cable TV run?
Post by: frank on June 03, 2013, 10:29:16 AM
Frank, Do you presently have a phase coupler or coupler/repeater between the phases?
XTB-IIR is the gold standard one. My lowest signal is about 1.5 volt as measured by a XTBM test meter. With my XTB-IIR installed.

Have you done any X10 troubleshooting. To remove a signal sucker or noise maker.

http://jvde.us/x10_troubleshooting.htm
http://www.act-remote.com/PCC/uncle.htm
http://www.davehouston.net/

I do have a phase coupler 'available' in my breaker panel between the legs.  However, currently, I have all my x10 stuff on one leg and I have the phase coupler turned off. 

The farthest device I have from the cm15a is a lamp controller for front yard landscape lights, which was on the opposite leg.  It was plugged into the same duplex outlet as my sprinkler controller and worked fine until  placed a surge arrestor at that particular outlet for my sprinkler controller.  Doing so shunted the signal to the lamp controller so I moved the lamp controller to another outlet, which is on the cm15a side.  And then I turned off the phase coupler.

While I could place a filter inline with the surge arrestor, I'm not sure whether doing so might reduce the arrestor's effectiveness.

I have found a couple signal shunters and have placed filters inline with the AC for those.  I need to do something to increase the signal level to that far point.

I hate to hear the results of JeffVolp's recent test.  That is discouraging.
Title: Re: X10 RF on a cable TV run?
Post by: bkenobi on June 03, 2013, 11:28:15 AM
Jeff's results are similar to a set of testing I did in my garage.  I have a wired motion sensor that was added to the end of the outlet run in my garage (due to convenience).  I controlled the lights on the front of the house with the motion sensor via a power flash plugged into the same outlet as the motion sensor.  My guess is that there's a 100ft run from the distribution panel to that outlet through the walls with at least 8 outlets in series.  I did extensive testing with a XTBM and found that the signal strength drops considerably along the run (checking one outlet to the next while triggering the PF).  By the time I got to the distribution panel, I was down to a signal strength <1.0 when I started out at >7.0.  As a result, I only had moderate performance from that setup.  I found that I missed up to 15% of the signals from the motion sensor resulting in no lights when I wanted them to turn on and lights staying on all night since it missed the "end motion" signal.

The solution for me was to move the power flash to an outlet next to the distribution panel and run a dry contact wire out to the motion sensor.  Since it's only opening/closing a contact, the length of wire doesn't affect performance whereas transmitting X10 over the same length certainly was!
Title: Re: X10 RF on a cable TV run?
Post by: frank on June 03, 2013, 11:55:24 AM
Jeff's results are similar to a set of testing I did in my garage.
...
The solution for me was to move the power flash to an outlet next to the distribution panel and run a dry contact wire out to the motion sensor.  Since it's only opening/closing a contact, the length of wire doesn't affect performance whereas transmitting X10 over the same length certainly was!

Again disappointing!  While running the wires like you did solved the problem, it is unfortunate that such measures have to be taken.  Perhaps the transmit levels of the x10 devices need to be cranked up by 5v or so.

I've been looking to buy an XTBM for a year or two.  I expect I would be able to, in effect, raise signal levels through the use of one. 
Title: Re: X10 RF on a cable TV run?
Post by: dhouston on June 03, 2013, 12:56:20 PM
While I've not done the calculations myself, an EE acquaintance tells me that the inductive reactance of lamp cord and most romex at 120kHz is 20,000 times what it is at 60Hz.

It's a shame that X10 went to a USB interface for the CM15A. Long runs of a low speed serial link are not much of a problem.

This thread does make me wonder how well X10 works in Europe where Cenelec limits PLC signals to ~2.5Vpp.
Title: X10 RF on a separate cable run?
Post by: frank on June 03, 2013, 03:42:15 PM
Makes me wonder whether you could pick off the 120kHz signal at the cm15a outlet point with a capacitive high pass filter, maybe even a series resonant LC circuit, then use coax to run that over to the breaker panel and reinsert it there using a similar series circuit.  At the breaker panel, you could use a dedicated breaker.... or have two of the little series circuits and feed each of two breakers to catch both legs.  (not entirely legal -- so mount a dedicated 110 (220?) vac outlet right at the breaker panel and connect the LC circuit to the AC line there?)

Don't know what the loss of 120 kHz would be in coax, but it would certainly be much less than using electrical wire.  Much cheaper too.

I suppose there could be a problem with the original cm15a signal being out of phase with the signal carried on the coax.  But it would seem the coax carried one would be quite a bit higher than the cm15a signal (capture ratio helps).  Or you might just get inside the cm15a and reroute the signal away from the AC plug to a small jack on the module and just bypass the CM15a to breaker panel AC path all-together.

You would, most likely, want to be careful not to electrocute yourself or an acquaintance.

Title: Re: X10 RF on a separate cable run?
Post by: dhouston on June 03, 2013, 05:32:18 PM
Or you might just get inside the cm15a and reroute the signal away from the AC plug to a small jack on the module and just bypass the CM15a to breaker panel AC path all-together.
That might be doable - the PLC output can be separated from the PLC input rather easily just by disconnecting pins 5 & 6 of TC1 and routing the signal over the coax. You should use an isolation transformer at the insertion point. There's a copy of the CM15A schematic here.
Title: Re: X10 RF on a separate cable run?
Post by: JeffVolp on June 03, 2013, 05:37:10 PM
Makes me wonder whether you could pick off the 120kHz signal at the cm15a outlet point with a capacitive high pass filter, maybe even a series resonant LC circuit, then use coax to run that over to the breaker panel and reinsert it there using a similar series circuit.  At the breaker panel, you could use a dedicated breaker.... or have two of the little series circuits and feed each of two breakers to catch both legs.  (not entirely legal -- so mount a dedicated 110 (220?) vac outlet right at the breaker panel and connect the LC circuit to the AC line there?)

That would probably work pretty well - especially with series-tuned LC networks at both ends.  You could ignore possible destructive cancellation of the X10 signal by just isolating the CM15A "network" from the powerline with the XPPF filter.

Of course, just connecting a repeater at the distribution panel would work too.

Jeff
Title: Re: X10 RF on a cable TV run?
Post by: frank on June 03, 2013, 06:31:08 PM
Thank you for the schematic.

Interesting...  What if you removed the two connections between the AC line and T2 and connected the coax to T2?  Maybe you go ahead and ground one side of that winding.  And use the .22 uf cap for isolation on the other side.  Maybe not have to worry about an LC circuit on that end?  

On the panel end, would you really need to use anything but another cap?  Wouldn't it seem that if the signal circuit of the cm15a just connects to the AC line, that you wouldn't have to worry about a tuned circuit?  Perhaps it would give you a little better signal though.

I'm not sure if doing this would have an effect upon the tuning of tc1.  Maybe that isn't a tuned circuit.

Title: Re: X10 RF on a cable TV run?
Post by: Brian H on June 03, 2013, 06:46:39 PM
CM19A?
It is a USB interface. Doesn't get near any AC power connections and uses RF to a transceiver.

FCC Database has the CM15A in it. Including the schamatic you have {with the added decoupling caps X10 did not include on the board} and the RF Daughter boards.
Along with other things like a Parts List. TC1 is a tunable coil.

http://transition.fcc.gov/oet/ea/fccid/
Grantee B4S
Product CM15A
In the details Tab.
Title: Re: X10 RF on a cable TV run?
Post by: frank on June 03, 2013, 07:05:20 PM
CM19A?
It is a USB interface. Doesn't get near any AC power connections and uses RF to a transceiver.

I apologize for the confusion.  I meant cm15a.  I edited my post to reflect that.

Thanks for the link Brian.  So we'll have to be careful with TC1 to ensure its tuning is not altered. 
Title: Re: X10 RF on a cable TV run?
Post by: dhouston on June 03, 2013, 09:07:45 PM
Interesting...  What if you removed the two connections between the AC line and T2 and connected the coax to T2?  Maybe you go ahead and ground one side of that winding.  And use the .22 uf cap for isolation on the other side.  Maybe not have to worry about an LC circuit on that end?  

T2 is needed to receive from the powerline as well as isolate the CM15A circuitry. A 1:1 isolation transformer (e.g. Murata 78250) at the insertion point keeps the coax isolated from the mains. TC1 is already isolated by T2 and other components.

Also, my suggestion eliminates any phase issues as the CM15A no longer sends PLC locally.

Using only a cap for coupling risks electrocution if the cap shorts.

EDIT: By using a 1:1:1 transformer, you could couple to both Line1 & Line 2.
Title: Re: X10 RF on a cable TV run?
Post by: frank on June 03, 2013, 10:54:24 PM
All good information dhouston!

I'll pursue it.

Thank you.

Frank
Title: Re: X10 RF on a cable TV run?
Post by: dhouston on June 04, 2013, 06:38:24 AM
Another point - the purpose of the 0.22F cap (C7) is to attenuate 60Hz while passing 120kHz. Jeff might be able to model this for the best cap/transformer combination.
Title: Re: X10 RF on a cable TV run?
Post by: dhouston on June 04, 2013, 07:41:35 AM
Another point - the purpose of the 0.22F cap (C7) is to attenuate 60Hz while passing 120kHz. Jeff might be able to model this for the best cap/transformer combination.

In a similar application, NXP uses 47nF and 47H in series with the 78250 transformer winding. See p40 of...
With a 1:1:1 transformer you can send to and receive from both phases.

Use X2 rated caps - they are designed to fail open.
Title: Re: X10 RF on a cable TV run?
Post by: frank on June 05, 2013, 05:52:23 PM
Thank you dhouston.

Good points and the circuit is a nice find.  I had forgotten what 'x2' meant.  But this is a very good use of it.  And the use of a 1:1:1 transformer is ideal.

It has become painfully apparent that I need a way to measure the results to determine the advantage of this effort.  I should take primary readings prior to making the change.

JeffVolp, per your suggestion of using a repeater; does the repeater increase the signal on both legs?

Frank
Title: Re: X10 RF on a cable TV run?
Post by: JeffVolp on June 05, 2013, 10:51:54 PM
JeffVolp, per your suggestion of using a repeater; does the repeater increase the signal on both legs?

Any repeater located at the distribution panel will increase the signal on both legs (assuming it is connected to both legs).  The XTB-IIR will increase signal levels well beyond those produced by other X10 repeaters.

Jeff
Title: Re: X10 RF on a cable TV run?
Post by: frank on June 05, 2013, 11:06:11 PM
Any repeater located at the distribution panel will increase the signal on both legs (assuming it is connected to both legs).  The XTB-IIR will increase signal levels well beyond those produced by other X10 repeaters.  Jeff

Does the repeater accept input from either leg and then repeat a delayed message to avoid clashes with the original?
Title: Re: X10 RF on a cable TV run?
Post by: JeffVolp on June 05, 2013, 11:13:25 PM
Any repeater located at the distribution panel will increase the signal on both legs (assuming it is connected to both legs).  The XTB-IIR will increase signal levels well beyond those produced by other X10 repeaters.  Jeff

Does the repeater accept input from either leg and then repeat a delayed message to avoid clashes with the original?

No, all repeaters that I am familiar with receive the first half of the X10 doublet from either leg, and then retransmit that in bit-sync with the second half onto both legs.  Delaying and retransmitting after the command is asking for trouble.

Jeff
Title: Re: X10 RF on a cable TV run?
Post by: Brian H on June 06, 2013, 06:01:22 AM
I would think delaying the transmission would mess up badly with the old dim method. Of turn Lamp Module fully On the send a stream of Dims to lower the level.
Title: Re: X10 RF on a cable TV run?
Post by: JeffVolp on June 06, 2013, 10:01:52 AM
I would think delaying the transmission would mess up badly with the old dim method. Of turn Lamp Module fully On the send a stream of Dims to lower the level.

Yes.  And many of us send sequences of X10 commands.  Delaying and retransmitting a command has the potential for colliding with another command being sent shortly after the first one.  Even with collision detection, it is likely that both commands would be corrupted.

Jeff