CM15A mod to increase range using TM571 Antenna - (With Pictures)

[eagle]

Super!  You "da man"  csnet! 



r,
eagle

[Brian H]

Thanks for all the added information.

Some that have gone the 'F' connector route. Have used the WGL 40020 replacement antenna set for the V572A units.
Near the bottom of the page is the 40020
http://www.wgldesigns.com/v572.html

[Brian H]

I have been looking in the Mouser Catalog for some parts I need.
I saw an antenna for 315 MHz {315 MHz seems to be a standard X10's 310MHz is unique} that I may try along with a telescoping one that looked interesting. Hope to have more data in a week or so.

[HA Dave]

.... Hope to have more data in a week or so.

I will be looking forward to your findings! You do really good work and have already added a wealth of useful data and infromation to the forum. Thanks!

[Brian H]

Well I have these on order and will post findings.

http://www.mouser.com/ProductDetail/430-1415/?qs=sGAEpiMZZMv4cjTLgUCErRsJh4AhamaQ
http://www.mouser.com/ProductDetail/Linx-Technologies/ANT-315-PW-RA/?qs=K5ta8V%252bWhtamaM%2fIxDm76w%3d%3d

[Brian H]

Got the antennas and they are quite large in diameter. I may try one anyway but it is looking like a Dremel day. 

[DJ Cornfield]

I would not waste time with a little TM571 antenna.  I just finished replacing my little plastic CM15A antenna with a telescoping one from Radio Shack with excellent results!  It took only 2 minutes.

Here's the Radio Shack part number 270-1402 Replacement 34 3/8" Telescoping Antenna for $4.99.  You don't even need to open your CM15A to install this new antenna either.  Just grab the middle of the existing plastic antenna with a pair of pliers and pull upward.  The plastic housing will slide up and off.  It's made that cheaply.  Leave the elbow joint attached to the CM15A, as you're just pulling the vertical antenna plastic off.  You'll find a little gray wire inside, just hanging loose within the plastic tube.  You want to strip off the end of the gray wire's insulation (about one inch).  Then wrap the bare wire around the threaded hole in the base of the replacement metal antenna.  Do two wraps.  The replacement antenna comes with a screw which is too small to fill up the hole, but since you've wrapped the bare wire through the hole a couple times, the screw will thread into the hole and lock there, using the wire strands for filler.  Next step:  hold the metal antenna against the side of the CM15A case.  Run a couple lengths of black tape all the way around the case of the CM15A to hold the antenna up.  Extend the antenna all the way up.  If you have extra gray wire hanging down from the bottom of the antenna screw, just push it back into the CM15A case hole.  Plug CM15A back in somewhere.

My range tests with KR22A 4 Unit Credit Card Controller:
before mod, plastic antenna = only 12 feet in the clear, only 6 feet through 1 wall
after mod, metal Radio Shack antenna = 50 feet through 3 walls

[steven r]

My range tests with KR22A 4 Unit Credit Card Controller:
before mod, plastic antenna = only 12 feet in the clear, only 6 feet through 1 wall
after mod, metal Radio Shack antenna = 50 feet through 3 walls

Thanks for the post!
Any chance of pictures?

[bkenobi]

I would not waste time with a little TM571 antenna.  I just finished replacing my little plastic CM15A antenna with a telescoping one from Radio Shack with excellent results!  It took only 2 minutes.

Here's the Radio Shack part number 270-1402 Replacement 34 3/8" Telescoping Antenna for $4.99.  You don't even need to open your CM15A to install this new antenna either.  Just grab the middle of the existing plastic antenna with a pair of pliers and pull upward.  The plastic housing will slide up and off.  It's made that cheaply.  Leave the elbow joint attached to the CM15A, as you're just pulling the vertical antenna plastic off.  You'll find a little gray wire inside, just hanging loose within the plastic tube.  You want to strip off the end of the gray wire's insulation (about one inch).  Then wrap the bare wire around the threaded hole in the base of the replacement metal antenna.  Do two wraps.  The replacement antenna comes with a screw which is too small to fill up the hole, but since you've wrapped the bare wire through the hole a couple times, the screw will thread into the hole and lock there, using the wire strands for filler.  Next step:  hold the metal antenna against the side of the CM15A case.  Run a couple lengths of black tape all the way around the case of the CM15A to hold the antenna up.  Extend the antenna all the way up.  If you have extra gray wire hanging down from the bottom of the antenna screw, just push it back into the CM15A case hole.  Plug CM15A back in somewhere.

My range tests with KR22A 4 Unit Credit Card Controller:
before mod, plastic antenna = only 12 feet in the clear, only 6 feet through 1 wall
after mod, metal Radio Shack antenna = 50 feet through 3 walls

VERY interesting!  I'd love to see a couple pictures.  I'm getting close to 0' range with my keypad remote.  I might also suggest zip ties instead of "black tape" for aesthetics.

[ms]

All the posts that help increase the wireless range are very welcome. Thank you all.
I managed to increase the range between the motion sensors and CM15A without any soldering or modification of the original housings.
The trick is in passive resonant circuits where electromagnetic field (radiated energy) is coupled between the oscillator and the outside antenna through the air.
It is nothing new and old radio amateurs (or hobby electronic members) will remember antenna circuits with coils that were tuned that way.

Long story short - if there is still some interest for this topic, please reply and I will provide more detailed description with some photos.
The results without changing radiated power (no battery voltage alternation) were very good.
From having difficulties receiving motion sensor signals through one inner "wall" (drywall) and  6-10 feet distance, the CM15A now 'sees' signals through several walls, from basement, from outside the house, from the second floor etc.

[bkenobi]

Well, I for one am VERY interested.  I have close to 6' range without walls right now for some reason (probably the keypad transmitter).  I just got my phase coupler installed and things are working great on the PLC side, so now I need to focus on the motion sensors.  I picked up the 3 antennas Radio Shack currently carries and they look promising.  HOWEVER, if there is a way to increase range without modding the original, I'd love to see it's implementation.  I don't mind mods at all, but I generally prefer ones that are reversible...especially when they are unproven to work in all situations.

[anthonylavado]

@bkenobi:
1) Unfold and straighten wire coat hanger.
2) Measure and cut approx 18-19". Best to try 18.5".
3) Tape beside antenna on CM15A.

[bkenobi]

I know about the passive antenna concept, but I guess I forgot to try it in larger scale.  I tried a 9" copper wire, but that's probably no longer than the original antenna.  Perhaps I should give the 19" or 38" version a try before modding the box permanently.

If that doesn't work, I may just install the F-connector mod so I can try different antennas more easily.  Thanks for the suggestion!

[Brian H]

The original antenna wire is 9". Some of it is coiled and glued to the inside case. For reasons only known by X10.

[dave w]

The original antenna wire is 9". Some of it is coiled and glued to the inside case. For reasons only known by X10.

Maybe that is X10's idea of a "bottom load" antenna.