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Author Topic: Neighbor says I am on his alarm system  (Read 4828 times)
AD6KA
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Posts: 2237




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« Reply #15 on: January 27, 2010, 10:46:00 AM »

Unless it's wireless, the alarm system consists of many long wire runs in the attic or crawl space to every window, door, sensor, etc. So it essenially has a big "antenna" for RF to get into.

The "check for a proper ground" idea is a good one. When first installed, I had huge problems with my alarm system. The dolts had grounded it to a PVC water pipe! I am not joking. It was outside and dirty and I guess they figured it was metal.
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N9AVY
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Posts: 66




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« Reply #16 on: January 27, 2010, 10:53:22 AM »

AD6KA  ...  Do you have a picture of that PVC ground Huh?   I saw one once and didn't have camera with me. I've told the story about it over the years, but it's really worthless without pictures.

BTW, I've seen grounds attached to gas pipes (bad idea), conduit and to hot water pipes. Have even seen grounds to building trusses in factories.
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N9AVY
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« Reply #17 on: January 27, 2010, 11:04:34 AM »

The "alarm panel" by his front door is probably just the keypad to control the main box which is probably located in basement or some other part of house. If the RFI is coming through the speaker, my educated guess is that the cause is the speaker cable. You (or homeowner) need to tackle the RFI at the main panel, not at the speaker.  A choke at the speaker terminals in the control box (not keypad) may work.

Most of the time the control box is located in basement or closet and installers are too lazy to hook up a ground. Most of the boxes are painted steel. In the case of Ademco/Honeywell products a short jumper strap needs to be installed from the door to the box after scraping off paint a bit. But this is the last thing you want to do. As I said above, the problem is most likely the speaker wiring acting as big antenna. First try a snap on choke at the control box and if that doesn't work; then, replace the speaker run with shielded cable.

My own system has a speaker hidden in cold air return with about 15 feet of unshielded cable run. My station runs around 600 watts to a yagi or dual sloper and ham shack is directly above alarm panel.  No problems now or ever with RFI. There are several cable runs all over house for doors and windows (panel is a GE/ITI).
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W5XJ
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« Reply #18 on: January 28, 2010, 08:48:02 PM »

I had an issue of rf setting off a monitored smoke detector on my alarm system. My fix involved ferrite torroids on everything and i found my alarm panel was not grounded so we fixed that. So far so good, 40 & 75 meter barefoot no longer summons the FD. Maybe some 43 or 77 material on the feed to the speaker will stop it. Plus make sure the panel is grounded as well.

73 and good luck.

Grant KE5ZYP
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AE5JU
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Posts: 229




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« Reply #19 on: February 11, 2010, 10:16:46 PM »

No attempt was made to "fix" my neighbor's alarm system.  I showed him some printouts that basically say, sorry, but it's his problem, not mine.  I suggested he call the alarm company for action.

I have continued to operate and he has not complained.

Meanwhile, I don't think this will help his alarm system problem, but I will be adding a Low Pass filter which just arrived.
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W6LAR
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« Reply #20 on: February 17, 2010, 08:12:29 PM »

Ah, yes the neighbor from you know where. I had one that was a real winner. Right next door. She left me alone until one day I asked here to keep her dogs penned and not let them run all over my garden. She then filed a complaint with my employer telling them my station could be heard on her telephone and electric organ. Also claimed I had bragged to her that I had stolen company equipment to make my station signal stronger. By the way, I worked at that time (30 years) for GTE. So I got called into the office and asked what was going on. Lucky that most of us in the "business" were smart enough to know that I would not steal anything and there wasn't much the telco had to increase my power level. The company replaced all the house wiring next door and washed their hands of it. I was asked to keep a low profile but I told everyone "No Way!" I continued and never looked back.
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W8JI
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« Reply #21 on: February 20, 2010, 03:10:57 AM »

Bypassing a speaker is like peeing into the wind. Speakers are passive devices that contain no non-linear or semiconductor systems.

There has to be a semi-conductor present, or some other potentially non-linear components, to have RFI. Because of this any bypassing has to be done properly and near the non-linear device.

Unless the thing is radio receiver and you have an exceptionally dirty transmitter, a low pass at the transmitter will not help. There will only be one way to cure it, reduce the RF voltage present in the overloaded device. There are a dozen ways to do this, and unfortunately most of them involve work at the device being bothered.

I'm constantly amazed at how bad some systems are designed and how little most people, even engineers, know about how RF systems and how shields and filters actually work.

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AE5JU
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Posts: 229




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« Reply #22 on: February 21, 2010, 02:54:11 PM »

Thanks, Tom.  You're always helpful!

Yes, I'll just leave this problem to him and his alarm company. 

But I'm not going to quit operating.
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AE5JU
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Posts: 229




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« Reply #23 on: April 04, 2010, 08:08:02 PM »

I was operating today at only 10 watts, just carrier through the antenna tuner.  And he says I was still coming in over his alarm and it was annoying to him.

Well, it is not a power issue.  Again, no other devices are receiving interference, only his alarm system.

Since my first post I've also added a Nye Viking low pass filter.

His only option is to call his alarm company.  I told him I am willing to work with them, transmitting to see if whatever they do to fix the problem helps or not.  He does not want to call them because he does not subscribe to their service.  It was installed by the former occupant.

Well, that's all I can do on my end.
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WX7G
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« Reply #24 on: April 05, 2010, 06:35:25 AM »

Could a solution be to switch OFF the alarm system speaker?
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AE5JU
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Posts: 229




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« Reply #25 on: May 03, 2010, 06:55:21 AM »

My coax has been damaged.  It is LMR-240 and easily damaged by crushing the foam core by kinking.  You can see the kink about head high where someone grabbed it, twisted it to get a better grip, and yanked.  It is usually about head high coming out of my shop building, but it was hanging down about waist high when I got home from a hamfest yesterday.
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K9LJH
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Posts: 58




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« Reply #26 on: May 03, 2010, 07:04:13 AM »

I would be calling the police about now
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N5QMG
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Posts: 35




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« Reply #27 on: May 03, 2010, 08:12:40 AM »

My coax has been damaged.  It is LMR-240 and easily damaged by crushing the foam core by kinking.  You can see the kink about head high where someone grabbed it, twisted it to get a better grip, and yanked.  It is usually about head high coming out of my shop building, but it was hanging down about waist high when I got home from a hamfest yesterday.

Call the police and report the criminal mischief, be sure to show them your Federal license to operate at your QTH.  Put up a hidden surveilance camera too, you're going to need it.  I'd have him arrested for criminal trespass once you have proof.  Then I'd take him to small claims court to get a judgment for the damages.
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