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GREAT IDEA! Thanks for sharing it.

42 (97.7%)

**DON'T CHOOSE THIS!** (Poll is only for counting POSITIVES.)

1 (2.3%)

Total Members Voted: 39

[Alabama-Hokie]

I appreciate the link the photos look pretty good. However, I am more the mechanical type than the electrical type and would really appreciate the hand holding...

Dave B

[dave w]

I looked all over the place for these pictures knowing they were hid some place in addition to Accessha. Never thought to look at a "MAC" sight. Mike Furgeson at SHED is a genius at using home automation in new ways (i.e using the old Radio Shark free "CAT" bar code reader and Shed's  "Xtension" program to read the bar code of empty packages on the way to the trash can and having "Xtension" generate next weeks shopping list). Explore Sheds web site for some really great ideas.

[BaBaLou.]

We should consider doing something with all those pics and helpful out there. Sooner or later it seems they all fade away. This site is holding on to its treasures and we should take of them before its too late.
BaBaLou.

[Brian H]

Yes the loss of accessha and all the information was a very sad day for many of us.

I don't think the information was moved or released to Public Domain.
The CM15A Antenna Mod was copyrighted by accessha.

dave w, Gee the 'Cue CAT' scanners from Radio Shack. I have a few of them somewhere in a stash. 

[HA Dave]

Maybe we could recreate the mod. I have a spare CM15A [as I am sure many of us do]. Its worth thinking about.

[eagle]

This looks like a mod that is easy to implement which affords better reception than the simple CM15A antenna replacement. 

Just wondering though... I came upon this antenna at the Shack that looks similar in shape and construction.
http://www.radioshack.com/product/index.jsp?productId=2103641#tabsetBasic

It says "Covers 108-1300MHz with peak performance occurring in the 152-470MHz range."

More expensive than the DIY but wondering if it be as effective or better.

r,
eagle

[Brian H]

If you are creative. The construction data for three antennas are in the earlier part of this thread.

[eagle]

Yes, sir.    I'm actually going to do the DIY with the radiators and hang it in the attic.  Easy to build, inexpensive, and would be more effective since I can centrally locate it between all sensors.

I was just wondering about and offering the idea of the RS antenna just in case someone wants to pursue it.

r,
eagle

[Brian H]

eagle; Many may want a preassembled unit and your data will help some reading the therad. X10's 310MHz is also in the antennas peak performance area.

[eagle]

Just a quick FYI:

Instead of getting the combiner unit that the OP got, I found some possible less expensive alternatives.

The OP got the ZSC-2-1 from MiniCircuits.  The MiniCircuits site says it costs about $50 if bought in quantities less than 50.  Yikes!

The below splitter/combiners from partsexpress cost a whole lot less.
- http://www.parts-express.com/pe/showdetl.cfm?Partnumber=183-130  ($6)
- http://www.parts-express.com/pe/showdetl.cfm?Partnumber=180-351  ($6)
- http://www.parts-express.com/pe/showdetl.cfm?Partnumber=180-710  ($6)
- http://www.parts-express.com/pe/showdetl.cfm?Partnumber=180-714 ($3)

I might get one of these if I need to do a dual antenna like the OP.  The first one is spec'ed for 5-2150MHz.  The others simply say 1GHz bandwidth.  I'm not sure if that matters because I've seen some comments saying that they work fine.

Not affiliated with partsexpress.  Just thought I'd offer the info for those who might need one for this project or any other.

r,
eagle

[Brian H]

The ZSC-2-1 is over kill for this use.

I would think any of the ones you showed as long as 310 MHz was in its range would be fine.

I would imagine Radio Shack and other electronics distributors would also have some that would work.

[Frank3d]

I checked the CM15A threads and I can’t find where anyone mentions that there are two separate antennas on the CM15A, one for RX the small outside whip and one for TX a short wire on the inside of the unit. I would like to propose a dual antenna design or a combiner / splitter much like one mentioned in earlier posts to combine two external antennas but in this case to combine the TX and RX signals from the CM15A into one strategically placed outside 1/4 wave groundplane antenna cut to 310Mhz. My only concern with the splitter used as a combiner is it’s possible the TX RF power might hurt the receiver input if combined with it using a 50ohm splitter for 310Mhz. Otherwise the only alternative is two individual antennas one for the TX and one for the RX to really get max RX and TX data to and from the CM15A.

[HA Dave]

I checked the CM15A threads and I can’t find where anyone mentions that there are two separate antennas on the CM15A, one for RX the small outside whip and one for TX a short wire on the inside of the unit.

Here's one:  http://forums.x10.com/index.php?topic=17240.msg94900#msg94900

[mike]

I agree this was a well written, well thought out dual antenna idea and then implementation!  Coodos (is that spelled right??)!

I just want to raise the idea of DB loss on the splitter (about 3.5db per specs shown & typical of all 2:1 splitters for upto 500mhz), and db loss of the RG58 coax at 310mhz (see http://www.ocarc.ca/coax.htm) of 4db for the 50' run, an another 2db for each 25' additional run for total losses of 9+db per antenna........

Anyone ever do testing to see what db loss the std cm15a has over a std 1/4 wave antenna?  My far out guess as 30+yr extra class ham who's built lots of rf stuff, with 1rst class commercial license I used for years to repair commercial radios in this freq range, and Bachelor of Electrical Engineering, specializing in communications, is .....  -9db!!!

So it seems by the math that the std cm15a with its own antenna is probably equiv in performance if placed at EITHER attic location where the antennas are located now......  not bad for letting the cm15a communicate at the electrical box as stated..... good thinking....  so this idea gets best of all THREE locations!  SAME antenna receive performance as if placing the cm15a in attic location 1,  SAME antenna receive performance as if placing the cm15a in attic location 2, and SAME power line communications performance as placing the cm15a at the circuit breaker box.

I think if others like me who have finally placed their cm15a in 2nd story of house and how that helped reception....... they probably would agree with the above paragraph.

So the moral of my inputs is GOOD JOB! 

And if you want even better performance than placing the cm15a at either attic location, USE BETTER COAX!  You can reduce the losses from 4+2db to less than 1/2 or 3db if you just pick the better low loss coax shown at the website I listed above!  What would this mean in additional coverage for YOUR system?  Again my guess.. this additional 3db of signal (this means 2x the signal!) maybe another 30-50' of range added to your already what was it?  150'....

Some of us are a bit lazier and did the BNC cm15 adapter on cm15a at 2nd story location, then bought the really hi power power line repeater thing (forget the name of it but it pumps up to like 25vac on the line!) AND also bought the V572RF32 to extend the cm15a range too....  But we still don't get the range on our security devices that only the cm15a can decode as 32bit words, so guess what? Your design still won over our throwing $ 400 at it our way.

I'd give you points but I am just a peon too and can't

Way to go! 

[bcondemi]

Wow!, It's been a few years and my set-up still works perfectly...

Here are some of the missing photos that have seemed to dissapear over the years...I guess the image hosting sires eventually delete the photos. I couldn't figure out how to directly upload the photos here....so anyone that knoes how to keep these....here you go.
 
 
 







I've since changed computer to a Mac and don't have a PC connected to the CM15A anymore. What is the best solution for this? I've read mouse house (for the mac) is one idea. but then I need to link the usb from my mac laptop to the cm15A wirelessly (with a wireless usb sender...I guess).