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[Brian H]

The small receiver in the SC1200A is the same one as in the updated TM751.
As Mike has pointed out. It has a wall wart. The power line transmitter and zero crossing detector are in the wall wart and four wires connect to a 4P4C connector in the SC1200A.

[dhouston]

There's no way to send PLC through a wall wart transformer - you just cannot push enough current through one and that's especially so with switching supplies. So, since the SC1200 sends PLC codes, it must have a path to the powerline and my concern is that they used the same idiotically dangerous methods they used with earlier transceivers. The CM15A antenna is not isolated (although it is insulated). The fact that they did not use a similar, external antenna here is a concern.

Mike - I got and responded to your PM but I really want no part of the SC1200 unless I see a schematic. I don't want to feel responsible for anyone electrofrying themself.

[Brian H]

Dave, It is not a standard wall wart. It may look like one but it is not.  It is a total interface that provides DC power to the SC1200, sends the zero crossing data to it and has transmitter keying signal from the SC1200 to key the X10 power line transmitter in the interface.

There is a real power line transmitter board built into the interface. I have seen it and tuned it to 120KHz as mine was a few KHz off.
The transmitter coupled to the power line through capacitors and a isolation transformer.
The SC1200A chassis is not hot.
The power supply part is a linear one and not a switcher.
The receiver chip is the same one as in the CM15A. Hymark RX3310

I have not seen any schematics and kind of doubt there are any publicly available.

[dhouston]

You're probably right about the lack of a schematic since there was no need for an FCC filing. It may be isolated but, without a schematic that makes that clear, I won't touch it and will add a disclaimer to cover it, as I have for the TM751 and RR501, when we start selling CM11A antenna kits.

[dhouston]

For the CM15A antenna kit, I have designed a small PCB that will solder to a bulkhead 50-ohm BNC connector. The PCB has an RF choke, bias resistor and two capacitors plus thru-hole solderpads for +5V, GND & SIGNAL. The board is small enough to pass through the lock-washer and nut for mounting the connector. It passes 3.5V over the 50-ohm coax to power the preamp mounted in the base of the eggbeater antenna. Since my health prevents me from doing the assembly and handling packing and shipping, I designed it to be as simple as possible as I expect a nephew to take it over once everything is ready and he has no electronics/radio background. Most of the soldering is done with solder paste, a stencil and small toaster oven so he can carry on with it should I leave suddenly for med school.

I'm looking at a couple of small RF isolation transformers that appear small enough to mount along with two capacitors on a similarly sized PCB that will solder to a similar bulkhead 50-ohm BNC connector. If we can get them in small quantities and if the assembly can pass through the lock-washer/nut, I'll design an unamplified antenna that can be used with the isolation transformer/capacitor assembly and the TM751, RR501, SC1200 and perhaps other X10 RF devices where there is no isolation from the mains or where the isolation cannot be verified by a schematic. In most cases, adding an unamplified eggbeater will provide adequate range. Where it does not, users can add the TenTec 1001 or Ramsey SA-7 preamp kit (in the antenna base) and an external power supply. An external supply is required as powering it from the TM751 or RR501 would defeat the purpose of isolating the antenna circuit from the mains.

Assuming we can get transformers that fit, the second, unamplified antenna kit will be a couple of months down the road - I have an overwhelming amount of prototyping and testing to do on the Zarduino^TM project and that takes priority as a distributor is helping finance that.

In both cases, users will merely need to mount the BNC/PCB assembly and connect 2-3 leads inside the X10 device, mount the antenna elements on its base (Polycase LP-11F, which will have all associated hardware premounted) and connect a 50-ohm coax between them.

[luke03]

Assuming we can get transformers that fit, the second, unamplified antenna kit will be a couple of months down the road - I have an overwhelming amount of prototyping and testing to do on the Zarduino^TM project and that takes priority as a distributor is helping finance that.

Dave,

Sorry for changing the topic slightly. Where is your distributor for the Zarduino board? Is that available in US today?  I looked your web site about that project, it has so many different varieties of them. Look pretty interesting.

[dhouston]

Sorry for changing the topic slightly. Where is your distributor for the Zarduino board? Is that available in US today?  I looked your web site about that project, it has so many different varieties of them. Look pretty interesting.

The distributor (YourDuino.com) is in China. There may be a US outlet also. The Zarduino^TM boards will not be available until I finish all the testing which will likely be 4-6 weeks if all goes well or a bit longer if hardware tweaks are needed. At the moment I have about 100 PCBs (10 of each device) with another 50 or so coming. I need to assemble and test a few of each device before finalizing the designs. The plan is to offer them as kits but with all SMD components installed.

[luke03]

Dave,  thanks! Interesting web site, it sells relay boards and other stuff.  Look forward to see your boards listed there, too.

[mike]

For the CM15A antenna kit, .........users can add the TenTec 1001 or Ramsey SA-7 preamp kit........

Hi Dave,  I had sent tentec emails asking for noise figure on their amp, but got no replies, so ordered a couple anyway.  they just came in -- 5.5db noise added.  whew....  wondering if this will do any good at all or just cover up the small sigs....  sa7 said <4, which i thought was too hi....  i will experiment and report back results anyway since I have them.    sure hope u keep good source for those integrated amps with 1-2db noise figures!

[dhouston]

...sure hope u keep good source for those integrated amps with 1-2db noise figures!

It turns out that they're still available. I was just confused by Mini-Circuits revamped web page.

I expect to have everything on order by early next week and should have amplified antenna kits for the CM15A and unamplified kits for the TM751/RR501 available by late January.

I think you'll find the TenTec will be more than adequate although my own testing was with RF receiver modules like those on my web site rather than with X10 receivers. The HiMark is a superhet receiver so it should do OK. The biggest problem is that it's fairly narrow bandwidth may not match X10's poorly tuned transmitters. There was a thread where someone replaced it (in the CM15A) with an RM1SG which is a very wideband superregenerative receiver and got significant increases in range from various X10 transmitters.

• http://forums.x10.com/index.php?topic=21000.0

[mike]

Hey Dave,

I added the tentec preamp to input off an sc12a using small 2" piece of coax to feed it to the ant input of the rcvr and then reused the same 8" piece of wire antenna;  it appears the 5.5db noise figure makes the previoiusly working sc12 deaf now.  Guess with a better tuned antenna it may not just wipe out the receiver, but as standalone unit with crappy 1/4 wave vertical w/o a ground plane, it can't hear ds10's anymore.

BTW, ohm meter check and ac voltage checks to wall socket seems to indicate sc12 chassis (ground) and antenna are isolated from the power line.

[dhouston]

BTW, ohm meter check and ac voltage checks to wall socket seems to indicate sc12 chassis (ground) and antenna are isolated from the power line.

You are probably right but, without an X10 published schematic, the potential liability is too great.

[mike]

understood my friend!

[m82a1pa]

Hi Dave,

Any luck with the kit yet?

[dhouston]

Any luck with the kit yet?

I have 120 bare PCBs and all the needed components but haven't had time to build any just yet. Hopefully, they'll be available in a few weeks.