newbie help on wired or wireless pirs

[JohnD]

ha ha, Bernard has found another card to play when he is criticised for spouting his fanciful imaginings.

If somebody is going to make extravagant claims, unsupported by evidence, and he is unwilling to provide any estimate for the probability of the event he postulates occurring, then of course there is no reason for anyone to believe his scare stories.

To put it in brief:
He provides no evidence for his scare stories, so they can be dismissed.

 

[Europlex]

Well, just to, I expect, get someone going, I've often seen the testing results from all manor of alarm equipment over the years.
Very interesting by the way.

Its availability to the general public, I don't know.

Just think about it though, we are talking about the workings of SECURITY equipment. It wouldn't be so secure if every Tom, Dick or Harry had access.

All I do know is that there are stringent rules and regulations that have to be adhered to for the design and operating parameters for all pieces of security equipment.

 

[bernardgreen]

If John had spent 12 years specifying and designing communication systems and interfaces to link radio communications with alarm and monitoring systems then he would understand the basics of wireless communication protocols.

With that understanding he would probably have a different opinion about alarm systems using one way communications on a licence exempt radio channel from the opinion he has based ( apparently ) on experience of one DIY alarm system.

 

[JohnD]

If Bernard didn't waste his time in fanciful speculation about people building their houses next to transmitter aerials, he would admit that the probability, in an ordinary domestic house in an ordinary residential street, that a burglar will break into your home at th same fraction of a second that interference blocks one of your sensors, is infinitesimal.

The probability is in fact so small that Bernard refuses to estimate it.

He does like to throw abuse and contempt at people who disagree with his fanciful notions, though.

There are people who suspect that Bernard has never actually installed and used a Yale alarm. No doubt he is prosperous enough to buy something better.

 

[bernardgreen]

http://www.ofcom.org.uk/static/archive/ra/topics/research/rtcg/projects/project496.pdf

Radio Technology & Compatibility Group Project 496
Page 36 of 36
6.2.3 The consequences of interference or malfunction may be reduced in many applications by the inclusion of a failsafe feature or a manual override facility. Many manufacturers making use of SRD receiver modules in their products do not currently appear to be assessing the consequences (or probability) of interference to, or failure of, their product.

http://stakeholders.ofcom.org.uk/ma...ions-market-reports/cm05/overview05/spectrum/ has usage plots for Baldock and Southwark. Look at the use of 433, solid for the entire duration of the survey.

Another document ( which I cannot find in public domain) suggests the use of 433.92 is severely compromised in some urban areas.

One manufacturer of DIY alarms has assessed the probability and has included jamming detection which creates a full alarm if jamming persists. However due to the number of "false" alarms that might occur in areas where there is a lot of radio traffic on 433.92 Mhz the same manufacturer in the user manual also recommends dis-abling the jamming detection if false alarms occur.

And all that applies to problems from transmitters on 433.92 that are compliant, legally owned and operated. The use of non compliant equipment with or without criminal intent has a more serious affect.

 

[JohnD]

More fanciful speculation.

Please use your claimed expertise to estimate the probability, in an ordinary domestic house in an ordinary residential street, that a burglar will break into your home at the same fraction of a second that interference blocks one of your sensors.

Feel free to refer to your experience (if any) of using the Yale alarm you mention in an ordinary house to support your calculation.

 

[Europlex]

You're wasting your time Bernard, he's too ignorant to acknowledge your superior knowledge about the Radio Spectrum.

I know nothing about it, so I bow to your superior knowledge.

jd is one of those who will never admit he does not know something, so to get around it he just tries to bamboozle everyone with nonsensical questions and will never accept answers from people who have knowledge on subjects of which he knows NOTHING.

 

[JohnD]

fanciful speculation is worthless, no matter how often you repeat it.

When we see some actual results of real-world experience of a Yale alarm in an ordinary domestic house in an ordinary residential street, then we'll have something worth talking about.

I've seen some, have you?

 

[Europlex]

Ok, ask your mate about the one that was smashed up and fed back through the letterbox, because of the repeated false alarms.

I'm not going to bother about searching for it. It was a real life experience, but I doubt if you will believe it either.

 

[JohnD]

the plural of "anecdote" is not "data"

you'll be telling me next that wired systems don't get false alarms.

 

[bernardgreen]

you'll be telling me next that wired systems don't get false alarms.

PIRs do false alarm. I got called as key holder, to find a bird flying around the dining room. Me and the policemen had fun trying to get it out of the room so the alarm could be reset, in the end we gave up. Masked that PIR and reset the alarm. That was not considered false so did not affect police response.

I am very likely to be picking up a Yale system this weekend. One that has been replaced by a wired system.

 

[bernardgreen]

You're wasting your time Bernard, he's too ignorant to acknowledge your superior knowledge about the Radio Spectrum.
.

He knows that so far the door sensor has alerted the panel every time the entry door was opened. That proves the system works.

Obviously none of the neighbours has one of these

http://www.modelhelicopters.co.uk/flycam-one-hd-1080p-with-433mhz-remote.html

A recent discovery was cordless headphones ( suspect UK illegal ) affecting a legal 433.92 Mhz telemetry link. The telemetry link has had to be replaced.

He will never change his opinion until the alarm does fail during a buglary. I assume he has left the jamming detection enabled so it will go into tamper ( jamming ) alarm if an intruder disables it before entering.

The smashed alarm through letter box is not an isolated incident, with the increasing use of 433Mhz jamming detection will give rise to more alarms sounding for no apparent reason so more and more will be "dealt with" or will have jamming detection turned of leaving them vulnerable to intentional jamming to disable the alarm during a break in.

 

[Europlex]

the plural of "anecdote" is not "data"

you'll be telling me next that wired systems don't get false alarms.

It is not an anecdote and as I've told your mate many a time I am NOT a liar.

In answer to your line two, don't be so stupid. Clutching at straws now are we?

Q. What is your experience of alarm systems then, other than your DiY at home?

 

[JohnD]

Yes, it is an anecdote.

That is not relevant to your straw-clutching.

You were silly to raise the possibility of a false alarm as if it was a problem that occurred only on the alarm type you disfavour.

Fanciful speculation is what you are doing, and you know it. When you admit the size of the probability that, in an ordinary domestic house in an ordinary residential street, Interference will block a sensor at the same fraction of a second that a burglar breaks into your home, then you'll have started to talk about reality. However we both know that would show up the absurdity of your smears, so you won't do it.

 

[bernardgreen]

John cannot accept that there are transmitters other than Yale alarm system transmitters which can legally transmit on 433.92 Mhz for several continuous seconds.

He cannot admit that there are transmitters which are legally on sale in the UK but transmit continuously in contravention of the regulations applicable to licence exempt use of 433.92 Mhz

He cannot admit that there are transmitters wihich in the hands of criminals will knock out ALL message transactions on 433.92 Mhz.

He is right in saying that the chances of another Yale alarm blocking a system at the split second a burglar triggers an alarm are small. He is however wrong to assume that there will not be other transmitters active and blocking the channel at the split second a burglar triggers an alarm.

A recent incident was a telemetry link using 433.92 Mhz that had been working for many years. Just after Christmas the data error rate increased making the link un-usable for many hours in evenings and weekends. Day time the error rate was as before Christmas close to zero. An off air monitoring of the channel identified that the channel was occupied by transmissions that appeared to be digitally encoded music ( suspect cordless head phones ). The conditions for use of licence exempt channels include the requirement for the equipment to tolerate other users on the channel. Therefore "interference" from another legal and compliant transmitter cannot be stopped by enforcing the user to stop using their equipment..