I can assure you, i'm not.
What you experience down at the cheapskate/tightwad end of the market - the one you frequent - does not reflect the market as a whole.
Yale Premium Alarm Hsa6400 Wirefree Alarm Kit
- Thread starter Chrispace69
- Start date
What you experience down at the cheapskate/tightwad end of the market - the one you frequent - does not reflect the market as a whole.
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The "connection" between the sensors in a wireless system is NOT secure and if the alarm depends on secure communications then the alarm is not secure.
Correct
I do not think manufacturers will publish such evidence and some owners may be too embarrassed to admit the system they purchased was not as good as they were led to believe it was.
And leads to either a cry wolf situation where the alarm is ignored or the owner is forced to turn off the jamming detection.
to comply with the requirements of licence exempt wireles equipment
No that is not what happened, they realised there was interference and used a radio technician with the necessary test equipment to conduct the investigation
The interference was from a compliant use of the licence exempt channel.
The change to a wired system from a compliant wireless system was because the owners recognised that their compliant system was, under some circumstances occupying the channel to such an extent that nearby domestic alarms were being compromised.
Your experience is then subject to questioning. How many of the thousands (?) of systems you have installed do you regularily follow up for information about how reliable they are ?
My experience includes 12 years of designing equipment that had to rely on radio communications because one or more items were mobile ( person, vehicle or equipment ). Even equipment intended to be used on assigned and licenced frequencies where the equipment was, under the licencing authority's control, the only equipment in the area on that frequency it was still necessary to make adequate provision to ensure the equipment would work when there was activity on the frequency from a remote system.
That assertion applies to ALL things, they do not work if they are not turned on.
It is not a parameter in deciding the risk of a system being compromised by interference or intentional jamming.
Have you considered the possibility that the alarm system was allowed to fall into disuse because the owners were not satified with it, or the neighbours required that it be turned off ( and batteries removed ) after too many disturbed nights. There are two such in this village that I know are defunct. ( one low cost wired and one wireless ) there may be others.
You can when determining the specific risk of an alarm that has been correctly set not operating as a burglar alarm when needed.
M
mdf290
Ok then you have kept us in suspense long enough.
What are the statistical chances of a wirefree alarm failing due to inteference when set.
Could you also give the statistical changes of a wired alarm not activating when set.
and as a control could you give the statistical chances of of a two way wireless alarm failing when set.
If you come back with anything other than figures then you are basically a troll , an intelligent and informed one but STILL a troll.
Post up your records Yaleguy3
You do have them don't you? - thought not.
If you had any idea about the figures you'd realise how stupid your request is.
You really have next to no idea about the industry but still try to play the big i am.
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M
mdf290
If I fit an alarm and someone gets burgled and it does not go off..
Do you think
A. The homeowner will just shrug their shoulders . . or
B. They will ring me up asking what the hell they paid good money for and why didn't it work?
Thats where my stats come from and giess what? Not a single phone call with the above scenario ever...
I call that reassuring.
Now you have actual statistics but I am guessing you will not reveal them.
The answer depends on location, time of day and involves the assessment of the channel occupancy at the time. And you must not forget the statistical chances of the alarm sounding when not set. ( one manufacture accepts this can happen "due to interference" and provides mean to prevent it being a source of noise pollution )
Again it would require assessment of the system but this assessment would be much easier to do and far more accurate as everythin is under the control of the installer and user. There are none of variables that are present in all wireless based systems.
Again the assessment has to be site and system specific.
A wireless based alarm on a crofter's cottage ( or bird sanctuary office ) on a Scottish Island will be probably 99.9% reliable ( passing ships may have radios in use that affects the alarm ) while the same alarm in a busy residential area will have a significantly lower figure of reliability. In an area of business activity the reliability will be lower still.
I am more than happy to be that when confronted with a person selling equipment the operation of which he or she does not fully understand.
Perhaps you can give some figures on the receiver's pass band. ( its response to signals not on its designated frequency )
Sadly the only real-life experience of an interfering signal blocking the sensor is mine (so far, zero in ten thousand) and mdf's (also low) and the one tale which may be true, of blockage in exceptional circumstances.
The answer to the question "what is the probability of an interfering signal blocking a sensor at the exact time that a burglar breaks into your house" will be the product of
(interfering signal occurring which blocks a sensor) and (burglar breaking into your house at that moment)
For example, in my case, that would be
(less than one in ten thousand) x (once in thirty years)
So extremely improbable.
I would be interested to see any other examples, but I fear it will all be nothing more than "ifs" "buts" and "maybes"
The answer to the question "what is the probability of an interfering signal blocking a sensor at the exact time that a burglar breaks into your house" will be the product of
(interfering signal occurring which blocks a sensor) and (burglar breaking into your house at that moment)
For example, in my case, that would be
(less than one in ten thousand) x (once in thirty years)
So extremely improbable.
I would be interested to see any other examples, but I fear it will all be nothing more than "ifs" "buts" and "maybes"
M
mdf290
Lets just do something - lets ALL go outside now and press the remote control central locking button on our keyfob and see if the car responds by flashing the indicators.
In fact I am going to do mine from inside the house through the glass of the window.
Ok test done FIRST time I pressed the button the car unlocked and flashed and guess what - the second time I pressed it the car locked and flashed.
no tricks
It happened without drama and with full reliability.
You will be interested in this test because it's operation is dependent on EXACTLY the same inteference free conditions that are required for a Yale alarm to operate safely.
Sorry Bernard , try your own car and see if it works too...hmmm.
I guess you should also be telling everyone to lock their cars with their keys because the remote keyfobs are unreliable...lol
How many people do you know Bernard who can't get their keyfobs to work on their driveways?.
(Of course I have noted your earlier stories relating to car remotes not working but the exact reverese logic applies that anyone who does not have trouble with their car remotes at home WILL NOT HAVE PROBLEMS WITH A WIRELESS ALARM EITHER.
Can we end this stupid discussion on that point?
Four or five who live close to a transmitter station. The maximum distance between fob and car antenna is reduced to a metre or so. I know of two locations where key fobs are suspect. I had problems when parked 50 yards from a hilltop site. The owner advised with remote locking to park at the far end of the site and walk. But that was 20 years ago so obviously out of date. A bit like the broadband router blanking out alarm system receivers.
(
It does indicate that when the car key fob was tested the channel was not occupied with interfering signals that confused the car's decoder.
If you research the coding systems and protocols used in car key fobs you will find most of them are a different (better) standard to the average wireless alarm system methods of coding.
Is that end it before you have to admit you cannot answer any technical questions about capture range of the receivers in alarm systems. Remind me are the receivers FM or AM ? And which is less prone to adverse affects ? From memory of the days of CB ( citizens band radio ) the AM sets ( illegal in the UK ) were the most troublesome while the more expensive FM sets were far less troublesome.
Bernard is determined never to offer an opinion on the probability of an interfering signal blocking a sensor at the exact moment that a burglar breaks into your house, which, of course, is the only thing that matters.
Fanciful speculation about theoretical possibilities are of little interest to homeowners.
M
mdf290
I would say its safe to say that if you don't have problems where you live locking and ublocking your car with your remote fob then you won't have problems with a wireless alarm . In fact I'd even say that test was too strict as the wireless alarms transmit at a higher power than a car keyfob
That statement proves you need to research before making statements about radio equipment.
The important factor is not the transmitter's power but the signal strength at the receivers.
The communication between a car key fob and the care is far more sophisticated than the simple communication used in the average DIY alarm system.
As the degree of interference.
An incident involving failed radio communication led to an enquiry pending legal action against the supplier and installer of the equipment.
Test results using a transmitter and receiver typical of those used in the system involved. Operating frequency 433.xx MHz
Packets sent at 5 second intervals for 2 days.
Non-compelled protocol ( sender cannot be aware of lost packets so cannot repeat packet if lost. )
Environment one
Free field ( one mile from nearest building )
Distance between transmitter and receiver 30 metres. Over 30,000 packets sent without loss.
Environment two
The average of five locations on the edge of towns. Distance less than 20 metres One packet lost in every 27,000 sent
Environment three
The average of four locations in residential areas. Distance less than 20 metres One packet lost in every 17,000 sent
Changed to semi compelled single repeat ( if sender does not receive an acknowledgement then the packet is re-transmitted once )
Environment three improved to a total of 4 packets lost in over 120,000 with 3 lost at one location.
The test was repeated at the environment three locations with the senders set to test for clear channel before transmitting and without repeats. No packets lost in 20,000 Delays before transmitting were not measured but rate of sending dropped from one every 5 seconds to an average of one every 8 seconds.
From the expert witness giving evidence to the enquiry
WI = Wireless interconnect.
NCCP = non compelled communication protocol
SCCP = semi compelled communication protocol
M
mdf290
Your report is actually ironically reassuring.
you may remember that I mentioned that the pir sensors do not go to sleep immediately they have detected movement and continue to report several more detections before the sensors go into sleep mode.
In that scenario given the probability that a person moving within a protected room is going to be picked up at least three times by the sensor makes the probability of an alarm failing to activate even given your worst case scenario figures in the region of 17,000/1 in favour of a positive response. If the home has been properly surveyed There will be at least four sensors (Two door contacts and two pir sensors) as a minimum making the probability of non of the sensors activating the alarm a very very very small percentage indeed...(Any mathemeticians out there?) At a stab I would put the figure at 68,000 to one on that the alarm will work.
you may remember that I mentioned that the pir sensors do not go to sleep immediately they have detected movement and continue to report several more detections before the sensors go into sleep mode.
In that scenario given the probability that a person moving within a protected room is going to be picked up at least three times by the sensor makes the probability of an alarm failing to activate even given your worst case scenario figures in the region of 17,000/1 in favour of a positive response. If the home has been properly surveyed There will be at least four sensors (Two door contacts and two pir sensors) as a minimum making the probability of non of the sensors activating the alarm a very very very small percentage indeed...(Any mathemeticians out there?) At a stab I would put the figure at 68,000 to one on that the alarm will work.
How many repeats and what is the time interval between them before the unit goes into sleep mode ?
The important factor is the reduction in reliability of the system as the test sites moved into built up areas.
You may also ask the mathmatician to work out the effect that the reduction in distance from 30 metres to under 20 metres would have on the test results.
Hint.
[1] signal strength of the required signal at the receiver is important
[2] the inverse square law applies.
The ratio of required signal to un-wanted signals is the critical factor.
If you are proficient in the use of wireless technology you wouldn't need a mathmatician to help you.
You may also ask the mathmatician to work out the effect that the reduction in distance from 30 metres to under 20 metres would have on the test results.
Hint.
[1] signal strength of the required signal at the receiver is important
[2] the inverse square law applies.
The ratio of required signal to un-wanted signals is the critical factor.
If you are proficient in the use of wireless technology you wouldn't need a mathmatician to help you.
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