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[dave w]

I am picking up all of my ds10s  inside my house, but I am not seeing any of my eagle eyes or active eyes that are outside of the house. They are at most about 60' from the antenna. I have set house codes to B and allowed for 2 number for each motion sensor. Any ideas of what I have done wrong?   

jrlafarge
FWIW
I didn't have any BNC's in the junk box so went with cheap "F" connectors. However I don't think the off the shelf receiver X10 is using in the CM15 is that critical of input impedance. My anttenna is a coax going up in the attic with 18" shield stripped back and cut away leaving the 18" center conductor. I went 1/2 wave because I did not have anything in attic that would serve as a ground plane for the 1/4 wave. (I did try a 1/4 wave using the peeled back shield to form a ground plane and did not see any differeince between it and the crude 1/2 wave.  I am getting 60' with that arrangement. What kind of range did you get before you modded the CM15? When does the CM15A pick up the motion detectors (do you have a Palm Pad you can carry around the home to check the outside coverage?) You can also boost the range of the motion detectors by using an 18" passive repeater next to the detector. Search this forum for "passive repeater" .

[jrlafarge]

The range was about 15' or so, now it covers all of the inside of the house with no problem.  My house is a two story at about 2600 sq ft.  I have one sensor in the forier right by the front door that turns on the lights when you walk though there.  That one works.  There is another sensor out side the front door about 6 feet away from that one that I do not see at all.  I will try the passive repeater and see if that works.  I found the post here about it already.
Thanks,
Robby

[x10challanged]

jrlafarge,  I did the coat hanger trick at first and didn't get enough range.  My house is little over 3000 sqft single story so I purchased the SR731 repeater off e-bay.  That gives me enough range to cover my house, garge/gameroom and pool shed and I was able to remove the coat hanger modification from my CM15.   I did extend the USB cable and use an electrical extention cord to mount the CM15 about 6' off the floor behind a door out of sight.  You may or may not get the same results I did, good luck!

[mrjtwill]

 
Ok.. I am new to the x-10 and have been initially very disappointed with the RF range. My primary goal was basic security (motion and door sensors) and wizy-wig lighting automation later. I spent 250.00 right off the bat and got all the new software plug-ins (OnAlert..etc..) First issue was using the Security Fobs.. NO RECEPTION FROM 6inches. GERRR. Well I read as much as I could and found some antenna mods. I am a total novice as it comes to soldering and stuff, but I thought what the h3LL I will try it. I bought a radio antenna from radio shack (17.00ish bucks) that allowed for multiple mhz with a BNC. Then got a F to BNC adaptor, F-Connector to attach to CM15A. So Far...... So Far I did get some better reception, BUT!!! my reception for the security fob works only on one side of the townhome (Weird). My office is upstairs East Side, but I get almost no reception on the West Side. Trust me this townhome is small and I can only imagine what people with 2000sqft homes must deal with getting this all to work. The PLC portion seems to be nearly flawless... but that RF is about impossible. Does anyone have a townhome situation? I hear some of you putting antennas in your attic... would that help me if I am in a TownHome? I have to try to boost my RF to ensure reliable security module performance....  I am not a RF or Antenna expert, but does anyone know if it is possible to put an antenna in the basement and one in the attic and connect them both to the same CM15A?

Thanks in advance..
John

[Puck]

First issue was using the Security Fobs.. NO RECEPTION FROM 6inches.

Are you aware that security remotes/devices have to be installed in AHP w/OnAlert before their signal will be received by the CM15A?

What are you looking at to verify that it wasn't working?

How many security remotes/devices have you tried? Do you have a regular X10 remote to test?

The reception range of the CM15A (as is) is bad, but 6 inches sounds more like a defective receiver than just the bad antenna issue.

I am not a RF or Antenna expert, but does anyone know if it is possible to put an antenna in the basement and one in the attic and connect them both to the same CM15A?

Yes it can be done: [User Idea] ULTIMATE DUAL ANTENNA Setup for CM15A

[MikeySoft]

There are several threads about increasing the range.  I'm picking this one for my findings. 

Background:
Like others, my CM15a has RF range problems.  I few years ago I read about adding an external antenna to improve the range.  I decided getting an RR501 transceiver was simpler at that time.

I've recently been reading additional threads about passive reflectors and simpler antenna modifications to the CM15a and decided to try some starting with the simplest ones first.

Findings: 
1. I taped a 9.5 inch 14 gage wire to the CM15a antenna.  It did not help.
2. I added a horizontal passive reflector (about 18 1/2 inch I think) to my motion sensors.  I kept the 9.5 wire on the CM15a antenna because I was too lazy to remove it.  It helps with one sensor but not with the furthest.
3. I opened the CM15a, unstuck the loop in the antenna wire from the sticky glue, slid the plastic antenna mount out from the CM15a case, and let the full length of the wire and plastic antenna dangle out and down the CM15a's outside.  The antenna is now longer and straighter but not perfect straight.  I kept the passive reflectors on the motion sensors.  This helped but seems intermittent with the furthest motion sensor.
4. I  changed the passive reflector on the furthest motion senor from horizontal to vertical.  Everything now works great!

Questions for the antenna experts:

1. I'm sure that making the passive reflector vertical helps because my CM15a antenna is mostly vertical, correct?
2. Because of how I have the motion sensor mounted.  The vertical passive reflector is now about 1/2 inch or so behind the sensor while my CM15a is in front of it (through exterior and interior walls).  Would this be making the sensor antenna more directional toward the front?

[dave w]

Questions for the antenna experts:

1. I'm sure that making the passive reflector vertical helps because my CM15a antenna is mostly vertical, correct?
2. Because of how I have the motion sensor mounted.  The vertical passive reflector is now about 1/2 inch or so behind the sensor while my CM15a is in front of it (through exterior and interior walls).  Would this be making the sensor antenna more directional toward the front?

#1 Yes. It's called antenna polarization. For best range all antennas should have vertical/horizontal orientation the same.
#2  Not sure from your description but don't think so. If your motion detector is any of the xxxEYE motion detectors, the internal antenna is a small coil loop in the upper left corner of the units PC board. Your (vertical)  radiator should be mounted on the left side of the sensor.

Maybe this old thread will help.
http://www.x10community.com/forums/index.php?topic=10982.0

[MikeySoft]

Thanks Dave, I'll read the link you gave later tonight.

My detector is a xxxEYE, MS14a I think.  It is not the active eye but still can be used outdoors.

I read in one of the posts that when a wire is taped to the CM15a plastic covering of the antenna, the antenna is still mostly omni directional because the wire is close to the antenna.  My wire is near the center but about 1/2 back so I was thinking (after I did it) it would make it more unidirectional.  Anyway it works. 

I'm also thinking that maybe because the CM15a antenna is now hanging down, it is no longer near the electronics of the CM15a which may help the antenna?

[dave w]

I'm also thinking that maybe because the CM15a antenna is now hanging down, it is no longer near the electronics of the CM15a which may help the antenna?

Possibly, but not sure. I suppose a test would be to try to compare receive range with the CM15A antenna pointing up (putting it next to the internal electronics)  and retest with antenna pointing down which puts it away from the electronics. I really doubt there will be much difference.

Back to the omni directional antenna. Antenna polarization still applies. For a "straight stick" omni directional antenna, the strongest radiation field for transmitter (and best reception for receiver) is perpendicular to the stick. The weakest fields are above and below the stick. However in our 2000 sq ft house, I really don't see much difference between vertical and horizontal mounting of the passive radiators. My CM15 antenna is a coax from the CM15A up through the ceiling  and "tywrapped" at the top of a vertical truss.  18" of the shield stripped away from the end to make a crude 1/2 wave antenna. Works pretty good considering it all came out of the "junk box". Good luck.

[coghlan]

The parts are actually called remote control (r/c) antenna tubes and apparently are quite commonly used with R/C race cars.  See http://hobbypeople.net/gallery/868612.asp

Most of them are 13" w/caps - which is too short for this mod - but the link above shows a 36" one.

The stock tube is about 5/16 (3.8mm) O.D. (outside diameter).  Has anyone tried to pull it out of the elbow?  Dunno if if the O.D. of the R/C tube is the same as the stock tube.

[Brian H]

Someone did the mod with some hobby shop RC antenna tubing. Probably at least a year ago; so finding the thread maybe hard to do. I believe they used a small amount of glue on theirs since the tubing was slightly undersized. I got some at a hobby shop and mine was also undersized. Will check the package tonight and see what size I had purchased and its length. If you try and pull the extra antenna wire from inside the case, it may or may not be hot glued to the case. Early one was a loose ball of wire; later glued around the case neatly.

[coghlan]

Does the existing (5/16") stock tube pop out of the elbow easily?  I tried tugging on it but it certainly didn't want to come out.

[Brian H]

No I believe it is glued or sonically welded together.

[BaBaLou.]

Hi all, if possible to ask a question in this area. I am attempting a to build a small antenna as listed here http://www.shed.com/tutor/mr26ant.html. I did not do the full mod on the CM15 as of yet but was able  to pull the tube out of the elbow on one unit and trimmed the tip of the wire about a half inch. The tube had little if any glue but seemed to have some form of sonic weld done to it, a little twist and make sure to hold the elbow with needle nose.
So as the "Turnstile" antenna shown has a 75 ohm coax connector. Q. If just connecting to the white wire on the CM15, do the connection to the middle of the balun coax end (outer thread is ground?) should I even use it at all 
Q2 Older threads referred to using 50 ohm connectors and wire over 75 ohm, using this antenna setup, would it make a real difference OR any harm to the CM15?.  
Q3 if making the Turnstile antenna and used a wire cross to firm it up in its shape, would that interfere in the reception of the antenna? use a wood backing instead
I did try using first just a 9.5" and later 18" wire just twisted to the CM15 antenna with some signs of improvement to its function, so its one step at a time for now with one more unit to try another mod on. Have not Cracked open any units as of yet, that's next so to see the glued part of the wire and also do a physical check and compare unit to pics and info on these forums and threads
BaBaLou.

[Dan Lawrence]

I thought there was a neat CM15A antenna mod using the antenna from a TM751 posted in this thread, but now it seems to have vanished.   Anybody know where it is?  The mod was well done with step-by-step instructions and pictures.