Yale Premium Alarm Hsa6400 Wirefree Alarm Kit

[bernardgreen]

The only issue I have there with what you were saying was the compliance issue.
The system that was losing packets was transmitting 80% of the time due to looking for lost packets.

Read the regulations. I think you will find it is 10% per transmitter,

In the scenario you have described if everyone had systems that relooked for lost packets then this scene could be repeated anywhere as each system tried to get it's voice heard above the others.

Most wait for a clear channel before attempting to transmit. Only possibly if sensors also have receivers.

The only logical error I can see in your tale of events is that Mr Day had turned off his jamming detection but his neighbour had not.

You then said that if the alarm had sounded it would have prevented the burglary as people would have heard it.

A valid point, but can be explained by variations in field strength between the two houses. A signal not continuous enough to trigger jamming detection will still be enough to corrupt activation signals to the point they are recognised.

Door sensor had worked reliably for several months.

 

[bernardgreen]

Bernard, are you ready yet to estimate the probability that an interfering signal might occur at the very moment that a burglar forces entry into the house?

.

John keep asking and maybe someone with a UK wide data base of transmitters using 433 MHz will spend a few days of expensive time on equally expensive radio contouring computor software and provide you with your required answer. Provide a post code and radus and the task will take far less time. The results will be valid only until such time as another system is installed in the area

Unfortunately as there is no record of installations of equipment operating on licence exempt channels there is no such data base so your question cannot be answered with any accuracy.

 

[JohnD]

The reason I keep asking you is that you like to post things like this

If your neighbour buys an identical akarm, his devices will all have different serial numbers and will not trigger yours.

Correct in that it is very unlikely to trigger yours but it may block the alarm signal from your sensor thus preventing your sensors from triggering your alarm. There is no way around that, it is a physical fact of shared radio channel use.

suggesting there is a problem of some magnitude, but it appears that you are unwilling to divulge what you think the magnitude is, although you have claimed that it is significant.

 

[bernardgreen]

John

Count up the number of sensors and other transmitters in the area of interest. Then find out their individual ratio of transmit to silence and apply the appropriate formula to obtain a channel occupancy value. This will then be used to calculate the percentage risk of a packet from a blind transmitter going out when the channel is clear. ( blind in that it has no way of knowing if the channel is occupied when it is told to send a packet. )

Do not forget that sensors with blind transmitters will be sending even when the alarm is not set. These will affect all receivers in range ( and often a bit beyond that ) So people moving from room to room in a house will cause packets to be transmitted from the sensors in those rooms and affect receivers in nearby houses.

The amount of packets needs to be taken into account when calculating the risk factor that an activation signal caused by a burgler will not be blocked or corrupted by a signal caused by someone moving in an adjacent or nearby house.

Do not forget that there are transmitters ( illegal ) that do not comply with the time contraints. There are uses other than alarms that legally use the radio channel and these also have to be taken into account.

There is no one answer to your question. The general answer is the more transmitters in the area the higher the risk of an activation signal being lost.

If you advocate, promote or install these systems then it is in the customer's interest that you have a full understanding of the risks and inform the customer of these risks. They are legal and compliant. That does not mean they are 100% reliable given that they use a licence exempt radio channel.

 

[JohnD]

That does not mean they are 100% reliable given that they use a licence exempt radio channel.

I haven't heard anyone ask for 100% reliability.

But you are reluctant to say if you think the chance of an interfering signal blocking a sensor at the same fraction of a second that a burglar forces an entry into your house is likely to be, say, in the order of one in a hundred thousand, or one in ten million. You have repeatedly said you think the chance is significant, so you obviously have an idea of what you mean.

 

[mdf290]

No burglar alarm is 100% reliable.

There could be errors in installation - a fault develops or the user simply forgets to set the alarm.

Even wired systems are not 100% reliable.

What of a sensor fails. It will alert the panel as a fault but that fault remains and if the home is burgled before that fault is rectified or discovered the alarm will fail. A large percentage of wired systems will fail if the power cuts out due to owners not upkeeping the systems or regularly maintaining them.

Your continued singling out of wireless systems as an absolute and verified security risk is out of all proportion to the risks you claim actually occuring.

A burglar alarms MAJOR role is to inform the prospective burglar that the house is alarmed.

This performs 95% of the function of a burglar alarm.
84% of burglars according to home office statistics would not burgle a home with an alarm.
They do not want to play Russian Roulette with their freedom.

So what are we talking about here when we talk about POSSIBLE inteference.
The probability of a wirefree alarm being burgled is no more than the probability of a wired alarm being burgled so in reality whether the system works or not has no effect on the initial detterent.
Then of the 16% of homes burgled we than have to whittle down to the percentage of wired alarms that will fail due to inteference.
We are talking seriously small percentages here Bernard if you want to really talk about the threat level of the problem you have identified.

Even the case you mentioned went on for such a period of months the problem could have been identified and sorted much sooner when the alarms had started to indicate inteference and prevented the burglary that occured.

The most revealling thing about any alarms efficiency is when I explain to people how they can set the alarm at night using the part set option the reply 85% of the time is , 'We won't be setting it at night'.
Even worse some people I visit actually tell me thay have had alarms before and never set them!

If users don't quickly learn how to use their systems and they set off the alarm and worry about their neighbours they simply stop setting it. In fact a usual comment I also get is that they never use them 'unless they are going away'.

Your body of evidence being one tale that could have been rectified pales into insignificance when compared to user behaviour.

You mentioned earlier that the adjoining alarm allthough able to alarm if the inteference was detected did not activate. You suggested that because the inteference was not detected it was not at the level to generate a response based on the panels algorithm. If this was the case then the inteference was not sufficient anyway to prevent all signals being lost and at some stage either of the door contacts or the two pir sensors should have generated a signal response which would have been detected by the siren and activated the alarm.

My money is on the fact that the owner had simply stopped using the alarm or had failed to set it.

 

[bernardgreen]

As you have revived it

The probability of a wirefree alarm being burgled is no more than the probability of a wired alarm being burgled so in reality whether the system works or not has no effect on the initial detterent.

That really does show your lack of awareness of how criminals think. We can discount the smash grab one item and run burglars as they will not be detered by any alarm going off. Most are so desperate for a quick fix they will ignore the risk of being caught. The only deterent against them is security that makes entry impossible.

But the thief who plans a burglary and will want to spend time looking for valuables and cash will be far less likely to attempt entry on a premises he knows has a wired alarm when he can defeat some types of wireless alarm before entering the property.

Even the case you mentioned went on for such a period of months the problem could have been identified and sorted much sooner when the alarms had started to indicate inteference and prevented the burglary that occured.

And what was necessary once the source of the blocking was identified. The blocking from other legally operating systems prevented an alarm from reacting to a break in. No matter how you try to avoid it it the fact is simple. The radio channel was not clear when the sensors sent activation signals.

It might be that some local criminal had a basic knowledge of how wireless linked alarms operated, realised what was happening and took advantage.

Once again I will repeat that in most situations the majority of wireless linked alarms will react as intended.

But they are not 100% reliable as they can be put out of action by a criminal before entering or made to appear to be so un-reliable ( false alarms ) that the owners turn them off.

That does not apply to wired alarms.

 

[JohnD]

... But they are not 100% reliable as they can be put out of action by a criminal before entering or made to appear to be so un-reliable ( false alarms ) that the owners turn them off.

That does not apply to wired alarms.

Just to clarify, you mean, of course, that wired alarms are also not 100% reliable, and that is is possible for a criminal to cause alarms that appear to be false, also on wired alarms, if he can be bothered and knows how.

Do you know if it is true that the most common reason for an alarm failing to sound in a burglary, is that the householder forgot to set it?

 

[Europlex]

Do you know if it is true that the most common reason for an alarm failing to sound in a burglary, is that the householder forgot to set it?

That is the most ridiculous piece of nonsense you have written.

How on earth can an alarm fail to sound if it has not been set? It can't even sound (during a burglary) if it has not been set. Duh.

 

[JohnD]

Surely you haven't missed the point?

If a burglary occurs when the alarm has not been set, it will not sound.

This is obviously one possible cause of an alarm not sounding in a burglary.

Do you know if it is true that this is the most common cause?

 

[alumni]

Surely you haven't missed the point?

If a burglary occurs when the alarm has not been set, it will not sound.

This is obviously one possible cause of an alarm not sounding in a burglary.

Do you know if it is true that this is the most common cause?

No it's not.


If it isn't set then it isn't an alarm.

So your argument is false.

 

[mdf290]

Surely you haven't missed the point?

If a burglary occurs when the alarm has not been set, it will not sound.

This is obviously one possible cause of an alarm not sounding in a burglary.

Do you know if it is true that this is the most common cause?

No it's not.


If it isn't set then it isn't an alarm.

So your argument is false.

Nonsense if you deal with domestic clients then you will know they don't always set their alarm , they tell you this when they talk to you.

You will also find people who will ask for a new alarm because they have been burgled as their old alarm was foobarred and they did not get round to fixing it or never bothered settting it but now they have been burgled they want a new shiny working system in which I happily oblige.

Your argument about it not being set therefor it is not an alarm???

Where did you learn logic??

The number of people burgled who's alarms don't sound because they never set it is a perfectly valid statistic when weighing up whether a systems potential to fail is weighed up against all the potential other reasons to fail, And compared to people not setting alarms a failure due to inteference is practically infinitesimal. Bernard with all his knowledge has only been able to come with one half presented example. Surely if it was such a large problem Bernard would have been able to deluge this site with anecdotal evidence , but evidently not.

 

[alumni]

Still in the Yaleguy mind set eh?

If the alarm is not set it is nothing more than a box on the wall. It doesn't even have ornamental value.

 

[JohnD]

I wonder why they're all avoiding the question

"Do you know if it is true that this is the most common cause?"

 

[mdf290]

Still in the Yaleguy mind set eh?

If the alarm is not set it is nothing more than a box on the wall. It doesn't even have ornamental value.

You don't even know your own business. The major reason peoiple have alarms fitted is because they know they will get a box on the wall. Thet then get lazy and stop setting the alarms because its more convenient foR themselves to hope the box on the wall will put burglars off than it is to keep up with system operation and servicing . People who actually set their alarm at night are in a minority because everyone thinks if they are at home they won't get burgled . Let's also not forget the amount of burglaries that happen when people are actually at home but the alarm is not set because people are moving about between rooms . These times alone represent a far greater threat than possible inteference