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[aslamma]

The range of the CM15A is terrible out of the box.  The slimline switches that were working before became useless.  There are many good mods out there, ranging from relatively time consuming and complex to very simple (but also effective mods).  My goal was to significantly improve range, while not becoming overly complex and still maintain a good looking piece of equipment since it would be exposed.  The solution was to use the TM571 antenna for the CM15A.  You will need to void your warranty to do this.

What you will need:
CM15A
TM517
#10 Washer (mine is from Home Depot)
Stranded wire
Super Glue
Wire strippers
Solerding Iron and Solder

1.  Take out the screw on the back of the TM571 first.  Then you need to separate the two halves.  I pryed it apart with a screwdriver and it popped out.  It took a good amount of force to do this.  Remove the antenna and find a #10 washer from a hardware store/home depot or wherever.  Remove the screw from the antenna and slip the #10 washer onto the antenna (as shown in the pic) and then reassemble the antenna to its base with that little screw.

2.  Now open the CM15A and cut the white wire.  Strip it and solder a new wire (stranded, not solid) to the end of the white wire.  Read ahead to get a good idea of how long this new wire should be (see picture 2).  Strip the end of this wire and fan out the strands.  This will improve the surface conductivity and bond area for the next step.

3.  Using picture 3 as a reference, bond the wire to the antenna base.  You will want to bend the wire 90 degrees where it is fanned out.  Skip ahead to view the final install of how it should look in the end.  You will now super glue the wire to the base.  Super glue does not cure real fast for metallic to metallic, so you will need to position it well.  I taped the antenna to the surface to it wouldnt roll, and just positioned the wire.  You may have to hold it down for some time if you cannot get it to position well.  Add the super glue and let it cure for a good 15 min or so.

3(a).  Alternative to step 3.  You may be able to use the existing TM571 connection approach, shown in figure 4, and bypass step 3.  There is a piece of wire with copper foil and adhesive on it that could probably be used.  I did not do this, so you are on your own here...but thought it was worth while to mention it.

[aslamma]

4.  Carefully insert the antenna into the slot.  It will be a little tight, but fits amazing well.  You can now see why you bent the wire 90 degrees before the bond.  Also, you can now see why you need the washer.  It will keep the antenna tight inside the housing, otherwise it would just flop around.  There is essentially no play in the assembly when this is done.

5.  Reassemble the case and you are done.

Result:
Before the mod, I could not get a slimswith to work more than 10' line of sight or 4' with a .5" wood plank in the way.  After the mod, I could go through 3 walls and over 50' using a slimswitch.  So needless to say, I was very happy with the end result.  And at least to me, this is the most cosmetically pleasing mod I have seen.  It looks totally stock (and in actuality it really is...kinda).

[HA Dave]

AWESOME... great pics too! You got a thank-you from me!

[aslamma]

Haha...it is I that should be thanking you and the other members here!

I took these pics on my new iphone...I think I was too close though and lost focus.  The iphone doesnt seem to take very good pictures, oh well...good enough to get the point across and super convenient.

[Brian H]

Nice mod. Thank you for sharing and the work it took to do the project.

[steven r]

They say "A Picture is Worth a Thousand Words" and yours really help to clarify what you've done. I've given you a helpful.

After some careful placement of my CM15A, I'm currently fortunate to be able to receive signals from pretty much anywhere in the house without modification except from a slim switch in the kitchen. I'd like to be able to place and get a signal from a DS10A at my mailbox, however.

....After the mod, I could go through 3 walls and over 50' using a slimswitch.  So needless to say, I was very happy with the end result.  And at least to me, this is the most cosmetically pleasing mod I have seen.  It looks totally stock (and in actuality it really is...kinda).

Hmm... If you have that good of reception from a slimswitch, that's about enough to tempt me to be brave enough to steal the antenna from a working TM517 to try it. Maybe the TM517 I'm having to use for my slimswitch now.

[aslamma]

"Before the mod, I could not get a slimswith to work more than 10' line of sight or 4' with a .5" wood plank in the way.  After the mod, I could go through 3 walls and over 50' using a slimswitch."

Put it this way, it was for all intents and purposes useless to me before the mod (since I mainly use slimline switches).  After the mod, all of my slimline switches work from any location in my apartment and I could get it to work about 20-30' from outside my apartment as well.  I would guess it improved effective range by about 3-5X.  I had an old TM571 from years back and it was kinda junky looking anyway.

[coghlan]

1.  Take out the screw on the back of the TM571 first.  Then you need to separate the two halves.  I pryed it apart with a screwdriver and it popped out.  It took a good amount of force to do this.  Remove the antenna and find a #10 washer from a hardware store/home depot or wherever.  Remove the screw from the antenna and slip the #10 washer onto the antenna (as shown in the pic) and then reassemble the antenna to its base with that little screw.

2.  Now open the CM15A and cut the white wire.  Strip it and solder a new wire (stranded, not solid) to the end of the white wire.  Read ahead to get a good idea of how long this new wire should be (see picture 2).  Strip the end of this wire and fan out the strands.  This will improve the surface conductivity and bond area for the next step.

3.  Using picture 3 as a reference, bond the wire to the antenna base.  You will want to bend the wire 90 degrees where it is fanned out.  Skip ahead to view the final install of how it should look in the end.  You will now super glue the wire to the base.  Super glue does not cure real fast for metallic to metallic, so you will need to position it well.  I taped the antenna to the surface to it wouldnt roll, and just positioned the wire.  You may have to hold it down for some time if you cannot get it to position well.  Add the super glue and let it cure for a good 15 min or so.

When you attach the washer to the base with the screw, are you soldering the wire to the washer or to the actual antenna base.

Does it matter if the old wire + new wire are a specific length (5 cm etc.).

I wonder if the telescopic antenna could just be purchased online, rather than trying to find an SR731.

[aslamma]

The extra wire gets attached to the antenna base, not the washer.

Not sure about the optimal wire distance...what I did seems to work quite good and you can see from the pictures about how long it should be.  Of course there is probably something more optimal.

Yeah, I would guess the antenna could be had anywhere...provided it had the same interefacing dimensions.  I thought the TM571 was a good choice because it has the proper length and interface, plus I did not need it after getting the CM15A.  Since a lot of people may have an extra one laying around (and its cheap), its a convenient choice.

[coghlan]

I'm a software guy, not hardware, so can I ask if it's possible to solder the blue wire to a 3/8" connector (similar to the one used in another thread re: making a coax connector for the CM15A) and screw that to the base of the antenna between it and the washer? 

How was the SR371 connected to the base of the antenna?  Soldered in place?

[BaBaLou.]

Hi Aslamma, Nice Mod , this one I am willing to give a try. As just asked, I presume you cant solder a wire to the antenna base? I will try to unsolder the black wire from the TM751 board and keep the rest attached. let u know how that works out. I will also be trying to use contact cement to attach the washer to the base.
My washer came from Home Hardware (other Canucks will get it)  .
BaBaLou.

[aslamma]

Guys, you can pretty much use anything to attach it.  I used super glue...I thought that was pretty clear??  But contact cement should work OK too...there are probably dozens of ways.  Just have to get it attached somehow...but I doubt soldering will work because the antenna base is not a compatible material.

[coghlan]

I was thinking that the screw you referred to was in the bottom of the SR731 antenna, the way toy walkie-talkies have a wire screwed to the bottom.  In this case, I presume it goes through the 90-degree joint and the base of the antenna is simply flat.  This is why I though one could simply attach a connector onto the wire and screw it to the base, but I guess not.

What is the length of the SR731 antenna when extended.

[Dan Lawrence]

X10 should modify the CM15A to include the same antenna as the TM751 in all future sales of AHP/CM15A.  That should cost no more to produce the CM15A, just substitute the TM751 antenna in the production line. 

[BaBaLou.]

Update, So far on the first CM15 originally bought in April of this year, Simple mod on the unit. Opened unit, White wire was not glued and was able to pull the full length out. I did connect a wire to the antenna ground on the board and then made a simple turnstile antenna and connected to CM15, With the antenna laying flat near the ceiling on the first floor of a ranch home 3000 sq'.
I now have total communication with the CM15 and so far 6 eagle eyes that range about 70 to 100 ft without missing a beat and all remotes used so far are coming in strong and consistent. It was simple and with a little tuning direction on the antenna, a very satisfactory reception. I still have 2 TM751 in the system and haven't tried to pull those out yet for total dependency on the CM15.
Unit 2, Just received it about a week ago. This unit I put in place of the first CM15 in my business. The business is a small cafe, just under a 1000 sq' no inner walls, but with a metal deck flat roof, Metal stud walls all around and kitchen equipment to make enough noise both for yourself as well as line noise to last a life time. Don't forget that the additional noise caused by other tenants in our building, many doctors and specialist with equipment and radiation and the list goes on and on. Well the first CM15 did OK, but many missed signals and many signals that just come out of nowere. With the new CM15 I haven't seen any of that yet. I did add a simple 5A plug in filter on the computer but that was it. So far the unit is working flawlessly. I am seeing all reports in the Activity monitor and the cams works well and lights turn off and on and dim and online is smooth and responsive. Nothing is missing yet. Lucky unit,? updated unit (haven't opened unit, if it is not broken or hurt then I wont touch)? There is a definite difference between the two units base on this simple comparison. The systems is slowly growing so as I do add to the home setup with more units, switches, modules, cams and security system, I will be very cautious and hope for a sweet and never ending expanding relationship to my home and business.