Digisender and home alarm interference

[Dave123456789]

hi all

I wanted some advice please

A friend installed a diy type home alarm for me with external siren, fobs and 8 sensors and 2 window shocks

It's a wireless gsm alarm gsm 900/1800/1900 bands pic can be provided if required

all was working fine when installed

Now some are not responding and he believes it's to do with my digi sender made by Nikkai 5.8ghz I have 1 sender 3 receivers

Anyway I never believed that but looking at manual (pls see pic) it seems he may have a point as I can see 433mhz on both manuals


I'm no whizz so that means nothing to me but if that is cause of interference and is stopping SOME (not all) sensors from working and also making my external siren intermittent

Does anybody have any advice ??


When I switch the digi senders off they work better - except the siren don't know if permanently messed up now??

Will all digi video senders be the same?
Can I change the 433mhz it uses?

Any other similar problems ??

 

[bernardgreen]

Welcome to the world of wireless.

You cannot have two systems that close together if they both use the same radio frequency and then expect them both to work perfectly.

Transmissions from one system will block the receivers of the other system.

 

[bernardgreen]

Missed the question about changing the frequency from 433 MHz

No you can't.

It would require a lot of component changes to the units and this would invalidate the type approval for their use as Licence Exempt wireless equipment

 

[sparkymarka]

Cheap Chinese alarm on 433 MHz with 9v battery says it all

 

[EightyTwo]

Switch off all the digi senders and receivers when you set the alarm - you won't need them 'cos you're going out!

 

[bernardgreen]

Cheap Chinese alarm on 433 MHz with 9v battery says it all

Doesn't matter who makes it, if something else is using the radio channel then it cannot be reliable.

In reality some cheap alarms may have a better chance of working (*) in the presence of other equipment on the radio channel since some of these cheap items ignore the limit on transmitter power and radiate a stronger signal. ( they shout louder than the legal and compliant equipment )

Working only in the sense that that the control panel can receive messages from the sensors when other equipment nearby is also using the radio frequency,

 

[Dave123456789]

thanks chaps

seems like i will have to bin the receivers which isnt ideal as i do love my sky in the other rooms but priority is obviously the alarm.

i wonder if i can get digi senders that dont work on 433mhz however??

a quick google suggest they all do

i kind of wish i went for the "licensed" frequency alarm pitched to me for a few more hundred quid.

it was 800 and something mhz and probably wouldnt have clashed with anything

i chose this one because in case i ever forgot to arm the alarm - i could do so by text.
whereas the other one u can only do by keypad/panel within the house. and if u forgot........tough luck.....

 

[bernardgreen]

The "800 and something " channel is also Licence Exempt and as such equipment using that has the same vulnerability to problems as that using 433.92 MHz. At present there is not as much equipment using 868 MHz but this will change and the 868 MHz channel will be as just as crowded.

i kind of wish i went for the "licensed" frequency alarm pitched to me for a few more hundred quid.

If you want a licenced channel you would have to apply to OFcom for a channel to be assigned to you and then pay them £75 for a five year licence. It is not easy to get a licenced channel unless you have a very specific reason for needing one.

 

[secureiam]

if that's the case why don't the major players pick a few between them..... £75 is jack for 5 years

 

[sparkymarka]

Still back to the wing Wong ting tong Chinese junk ! Lol

 

[bernardgreen]

if that's the case why don't the major players pick a few between them..... £75 is jack for 5 years

There just isn't enough radio spectrum to allow dozens and dozens of channels for small users.

 

[secureiam]

well people want to save a few pennies and don't know what they are buying, bin it, the alarm that is.

 

[secureiam]

how much do you need to separate them out, to be fair I am sure I have read your posts about the transmission strength and length causing the biggest issues.

a faulty radio device constantly transmitting will jam other signals. Think some wireless tech isn't tight enough. I suppose its like listening to a certain radio frequency as you travel across the country you start to pick up another station on the same frequency or very close to.

Think they need smarter wireless going forward.

just think how much information is going through you with all this wireless tech about scary and I know understand they want to use wireless power charging, scared we should be?

 

[Dave123456789]

i cant bin the alarm lol it cost me £650!!

i will just have to not use the digisender or just turn them off when i go on holiday.
when they are on half the alarm sensors work - other half dont

one question i do have please chaps:

Is it possible for the frequency clash to actually "kill" a part of the alarm for good?

as i said - half the sensors work when digi senders are on - half are intermittent.
when digi sender is off - all the sensors work.....except the external ringing siren.
it just doesnt beep anymore

i am wondering if the digisender clashing with it has actually killed it?

or should it be a case of when they're off - there is no longer a clash - and therefore the alarm should function completely?

 

[bernardgreen]

Think they need smarter wireless going forward.

No matter how smart the protocol is the bottom line is that if the radio channel is blocked no message will get through until the blocking signal ends. Even then the sender has to be aware that the message it sent when the channel was blocked did not reach the recipient otherwise the sender will not realise it is necessary to re-send the message. To achieve this re-sending function requires two way communication and some intelligence in all modules / nodes of the system

Is it possible for the frequency clash to actually "kill" a part of the alarm for good?

Very unlikely to damage components and thus put the system ( or part of it ) out of action permanently. But temporary "damage" to the system can happen as a result of blocking. In a two way system a sensor may repeat messages until it finally gets an acknowledgement "message received" from the control panel. The battery life will be shortened due the the repeated messages. In the worst case of prolonged blocking the battery may expire before the message gets through, by then it will (should ) be send "battery low" alarms but these will also fail to reach the control panel.

Some systems will, after a period of blocking, request status reports from all sensors / modules to look for any lost alarm messages and battery status.

Blocking can happen when any equipment operating on 433.xx MHz is transmitting nearby. Baby alarms, model helicopter remote controls and many many other types of equipment use 433.xx Mhz.

Some receivers can be swamped by strong signals on other frequencies. Swamping has a similar efeect to blocking in that the receiver cannot receive messages.