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Author Topic: My CM15A mod to increase RF range.  (Read 6149 times)

aslamma

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My CM15A mod to increase RF range.
« on: August 04, 2008, 11:54:16 PM »

So we all know the CM15A range is pretty bad right out of the box.  With the slimswitches I had a line of sight range of about 10ft and about 3ft if there was relatively thin wood board was in the way.  That is pretty horrible!

There are many mods out there ranging from relatively complex and time consuming to some very simple mods that appear to work good as well.  I had an old TM571 laying around so I took the screw out of it and pryed it apart (breaking it in the process) to get the antenna out.  (Hey, it was all or nothing at this point for me since I was ready to scrap the whole X-10 system).  Good news, the thing fits great into the CM15A...with a small mod.  This mod falls into the category of voiding your warranty, but is quite simple and very effective.

What you will need:
TM571 Antenna
#10 Washer
Relatively thin wire
Soldering iron (and solder)
**for a cleaner install you will need a drill, tap, and small machine screw**


1.  Get a #10 washer (hardware store or home depot) and slip it in between the tip of the TM571 antenna and the "base".  You will need to take the screw from the antenna out and reasemble it after you put the washer on. 

2.  Now cut and strip the white wire on the CM15A and solder on a new wire (with a small stripped end) that can be attached to the new antenna.  CURRENTLY, I stripped off the other end of the new wire and looped tied it in a knot around the antenna (but attached to the OUTSIDE of the box), leaving the shielded in to feed through the opening of the box.  HOWEVER, it would be better attach this wire to the antenna on the inside.  At a later date I will probably drill and tap a small hole in the antenna "base" and loop the wire around a small screw.  But since I was just *hoping* this would work, I pushed forward and just looped the other end to the antenna on the outside of the box.  This extra wire may not allow the box to close fully, but it will still be secure.

3.  Insert the antenna, with the washer, into the slot.  It will fit and look like it came from the factory this way (if you attached the new wire on the inside of the box).  Otherwise, you will have a small wire connecting on the outside, which may not even be a big deal to you.  Heck, I don't even know if you need to connect this wire up anyway?

Conclusion:
Night and day.  I could not get the slimswitch to go through .5" plywood at 3' before.  Now, I was able to go through 3 walls (including an A/C unit) at about 50' from the CM15A...with a slimswitch.  Since I rent and this was far more than what I needed for my applications, I did not find out where it would not work.  It worked at every location in my place and 30' outside of my apartment.  Thats it, I went from being super frustrated to extremely happy!
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-Bill- (of wgjohns.com)

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Re: My CM15A mod to increase RF range.
« Reply #1 on: August 05, 2008, 01:10:01 AM »

aslamma,

Welcome aboard!

Very nice write-up!   #:)

Gets a "thank you click" from me!

 >!
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aslamma

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Re: My CM15A mod to increase RF range.
« Reply #2 on: August 05, 2008, 01:50:25 AM »

Thanks :)

I started looking at the F connector mod, but realized it would be a lot of work to do that and then make an antenna to go with.  Plus it would not look good in an apartment if you cannot conceal it.  There may be some other simple mods out there that may work as good or better than this, but I liked the fact that it looks totally stock (in fact everything is X-10 still), and suits my range needs.  I also did it in about 30min and if I had to do it again it would just take about 5-10 min.

Of course, when and if I decide to tap a small hole into the antenna base, that will take some extra time.  I cannot think of another way to attach it.  Actually, I could probably just super glue it and if I really need electrical conductivity then silver epoxy should work quite well.  Now that I think about it, that sounds like a better idea.

http://www.amazon.com/Arctic-Silver-Thermal-Epoxy/dp/B00021LJ9I/ref=sr_1_1?ie=UTF8&s=electronics&qid=1217915206&sr=8-1
« Last Edit: August 05, 2008, 02:02:01 AM by aslamma »
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steven r

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Re: My CM15A mod to increase RF range.
« Reply #3 on: August 05, 2008, 12:38:45 PM »

Cool!
Any chance of pictures?
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JMac

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Re: My CM15A mod to increase RF range.
« Reply #4 on: August 05, 2008, 01:00:04 PM »

Why would you do the following ?
"Of course, when and if I decide to tap a small hole into the antenna base, that will take some extra time.  I cannot think of another way to attach it.  Actually, I could probably just super glue it and if I really need electrical conductivity then silver epoxy should work quite well."

If in fact this statement (from their web site) on Arctic Silver is true:

"Arctic Silver Thermal Adhesive was formulated to conduct heat, not electricity. Even though Arctic Silver Thermal Adhesive is specifically engineered for high electrical resistance, it should be keep away from electrical traces, pins, and leads."

I'm not trying to be a smarta**, just asking a question.  Thanks............
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aslamma

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Re: My CM15A mod to increase RF range.
« Reply #5 on: August 05, 2008, 01:28:30 PM »

Good question, I am not really sure...not my specialty and actually that is correct now that I think about it.  You may not get a true electrical path because of the epoxy, but I guess the better question is how sensitive is RF to a very small electrical resistance...and it will be very small.  I can probably call a buddy who is an RF engineer to find out...or just do it and see how well it works.  I can also cut the wire and grind off the adhesive if I have to.  Drilling and tapping a hole is kind of a pain so I want to find an easier solution. 
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coghlan

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Re: My CM15A mod to increase RF range.
« Reply #6 on: August 09, 2008, 11:20:20 PM »

Regarding adding 9.5" to the antenna, can the 2 ends overlap by any amount as long as the INCREASE in length is 9.5", or do the 2 ends have to be soldered end-to-end with no overlap?
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Brian H

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Re: My CM15A mod to increase RF range.
« Reply #7 on: August 10, 2008, 10:19:13 AM »

9.5" added not counting the overlap sounds right.
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