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[dhouston]

The Tested To Comply To FCC Standards is not 100% reliable as I have seen at least one TM751 with it but also with the superregenerative receiver. That may have just been some old inventory.

I believe it should only be applied to those with superhet receivers for which the FCC allows self testing.

[andyd]

I opened the TM751 that I had used for the testing.  I uses the Himark RX3310A.   I connected the receiver "data out" and ground to temporary test wires to bring them out of the case so I could see what the receiver was sending to the microcontroller.  I gave up on that very quickly when I found the logic ground of the internal circuits is connected to mains power hot!   I suppose its wired that way so the signal modulation can be imposed on the power line.  I should have checked before I wired the test leads but no harm done.

If I decide to continue with the instrumentation idea I'll probably have to put an opto-coupler inside the case.

Andy D

[dhouston]

The Himark RX3310A is a superheterodyne receiver. It is also used in the CM15A.

Most X10 modules are powered that way (CM15A has a transformer). It's a cheap, transformerless capacitive power supply.

I may have a KR15A in my junk box of older X10 modules. If so, I also have a new USB 'scope I've yet to setup and try - this may be  fun to track down.

[dhouston]

I did find one buried in the catacombs and with new batteries it flashes its red LED. I'll try to set up the 'scope and some type of receiver tomorrow afternoon.

Have you tried to capture what it sends after long presses as outlined in the user manual?
http://kbase.x10.com/wiki/KR15A

[andyd]

"Have you tried to capture what it sends after long presses as outlined in the user manual?"

No, not yet.   I don't have the device those codes are intended to activate so no interest at the moment.  I was just looking for a more powerful RF sender to activate my garage door opener timer.  Garage door opener is powered for 10 minutes after macro initiation then power is removed for security.

My RF monitoring technique was very simple. I connected a 17 inch length of wire between probe tip and probe ground.  I formed the wire into 2 turns and placed the RF sender on top of it.    The 17 inches wire just happened to be at hand.  it was not cut based on wavelength. With my Rigol scope it was very easy to trigger on the command sequence and to store it.

[Brian H]

SH10A Small Powerhorn.
Sending an On or Off to its address.
Then a Bright it will Ding or a Dim it will Dong.

Single Button Push:
R: A1 - 7:14:47 PM 4/20/2017
R: AOn - 7:14:47 PM 4/20/2017
R: ABright - 7:14:48 PM 4/20/2017
Sounded a Ding.

Hold Button longer:
R: A1 - 7:15:02 PM 4/20/2017
R: AOn - 7:15:02 PM 4/20/2017
R: ABright - 7:15:03 PM 4/20/2017
R: ADim - 7:15:04 PM 4/20/2017
R: ABright - 7:15:04 PM 4/20/2017
R: ADim - 7:15:05 PM 4/20/2017
R: ABright - 7:15:06 PM 4/20/2017
Sounded Ding Dong Sounds.
Changed to this:
R: A1 - 7:15:08 PM 4/20/2017
R: AOn - 7:15:08 PM 4/20/2017
R: A1 - 7:15:09 PM 4/20/2017
R: AOn - 7:15:09 PM 4/20/2017
R: A1 - 7:15:10 PM 4/20/2017
R: AOn - 7:15:10 PM 4/20/2017
R: A1 - 7:15:11 PM 4/20/2017
R: AOn - 7:15:12 PM 4/20/2017
R: A1 - 7:15:12 PM 4/20/2017
R: AOn - 7:15:13 PM 4/20/2017
R: A1 - 7:15:13 PM 4/20/2017
R: AOn - 7:15:14 PM 4/20/2017
R: A1 - 7:15:14 PM 4/20/2017
Started screeching

Released button:
R: AOn - 7:15:14 PM 4/20/2017
R: ABright - 7:15:15 PM 4/20/2017
R: ABright - 7:15:16 PM 4/20/2017

[Brian H]

SH624 Date Code: 10L51     
Code Button activated to generate a new Security Code.
Fast Tap Unit 1 On button for shortest transmission.
XTB-IIR Repeater Coupler turned Off.
Smarthome 1123CU receiving X10 Power Line commands.

Old RR501 Date Code: 02F23
R: A1 - 1:59:11 PM 4/20/2017
R: AOn - 1:59:11 PM 4/20/2017

New RR501 Date Code: 10G28
R: A1 - 2:00:25 PM 4/20/2017
R: AOn - 2:00:25 PM 4/20/2017

New TM751 Date Code 10E29:
R: A1 - 2:03:26 PM 4/20/2017
R: AOn - 2:03:26 PM 4/20/2017

Old TM751 Date Code: 00D17
R: A1 - 2:05:29 PM 4/20/2017
R: AOn - 2:05:30 PM 4/20/2017

CM15A Date Code: 05C10
Stand Alone in an outlet:
R: A1 - 2:06:54 PM 4/20/2017
R: AOn - 2:06:55 PM 4/20/2017
Connected to AHP and Registered in On Alert:
R: A1 - 2:18:44 PM 4/20/2017
R: AOn - 2:18:44 PM 4/20/2017

Security buttons did show in AHP but no activity on the power lines.
None of the other tested modules had any power line actions. With Security Buttons.

[dhouston]

R: MDim - 7:21:32 AM 4/20/2017 (Not sure what this is.)

That might be what I referred to as a microdim here...

[dhouston]

SH624 Date Code: 10L51     
Code Button activated to generate a new Security Code.
Fast Tap Unit 1 On button for shortest transmission.

I'm fairly certain that the SH624 only sends a single copy no matter how long the press is. At least that's how mine works.

Am I correct that all of your receivers report the SH624 but only the older ones report the KR15A?

[dhouston]

AGC typically sets the receiver at max gain until a signal is received then the gain is reduced as needed for that signal.

What I really meant was the Threshold Control of the Data Slicer which needs to see a few copies of the code to charge its capacitor. And I was thinking of how superregenerative receivers do things - I'm not as familiar with the low level workings of superheterodyne receivers.

You can see how the superregen works here...
https://www.laser.com/dhouston/rf-noise.html
and the Data Slicer circuit is shown 2/3 down this page...
https://www.laser.com/dhouston/RFTipsTricks.html

I suspect the comparator and Cpa, Cpb (shown in the RX3310A datasheet) function similarly but have never put a 'scope on them.
web.icasic.com:8000/WXSFXP/HIMARK/RX3310.pdf

[Brian H]

SH624 Date Code: 10L51     
Code Button activated to generate a new Security Code.
Fast Tap Unit 1 On button for shortest transmission.

I'm fairly certain that the SH624 only sends a single copy no matter how long the press is. At least that's how mine works.

Am I correct that all of your receivers report the SH624 but only the older ones report the KR15A?

Correct

[andyd]

I found a way to record the data output of the TM751 Himark receiver without electrocuting myself.   At first glance it appears that the receiver data output is a clone of the signal transmitted by the KR15A.  That suggests the problem is nothing to do with signal strength, antennas, or AGC response time.

I'll refine the test set-up a bit so I record RF and receiver output at the same time and then post the scope images.

Andy D

[andyd]

In the following images the top trace is the KR15A RF output and the bottom trace is the digital data output of the Himark receiver in a TM751.   It can be seen that the data output tracks the RF signal.   

[andyd]

At attachment limit for previous post.

The receiver output has lots of noise spikes until the AGC reduces sensitivity when the KR15A signal is received. The AGC recovery can be seen between words.

[dhouston]

In the follwoing images the top trace is the KR15A RF output and the bottom trace is the digital data output of the Himark receiver in a TM751.   It can be seen that the data output tracks the RF signal.

So it would appear that the newer TM751 and the CM15A receive the RF data out but interpret it differently than do the older TM751s. How much time is there between A1 ON & A BRT or A DIM?

And, my ACG is not the only crossed fingers typo.