Wireless doorbell

[bernardgreen]

AFAIK the RF spectrum is covered by an EU Directive, so yes.

It is not quite that simple. Frequency allocations across Europe are harmonised to reduce problems between two countries where wireless signals are crossing the border and affecting equipment in the adjacent country and where the frequency allocations in each country are made by different governments.

But from memory 315 MHz is not a licence exempt frequency in the UK. It is used by licenced users so any un-authorised use could affect the licenced users equipment and could lead to siezure of equipment and possible fines.

The CE mark, genuine or bogus, does not mean the equipment can be used as licence exempt wireless equipment. Equipment operating on an allocated frequency by a holder of a licence still has to be " CE approved "

 

[bernardgreen]

Gas~~flame~~flowing water is not the best option for reasonable control of hot water temperature as it requires accurate and fast responding control of the amount of heat going into the flowing water. To achieve this in a reliable boiler that can be sold for a sensible. customer friendly price is difficult if not impossible.

Gas~~flame~~thermal buffer store~~flowing water where the buffer store is kept at the temperature required for the hot water makes the design of the boiler a lot easier. The buffer store can be a hot water cylinder ( the best type of buffer ) or a small tank inside the boiler ( a compromise ). Some combi boilers do have that small buffer store. Sold as "instant hot water" or some similar marketing "advantage" when in reality it is a means to design a boiler that is slightly better suited to meet the owner's requirements for hot water supply.

 

[JohnW2]

But I know many home owners here in London use two separate boilers one for CH and kitchen hot water and a separate boiler fitted inside the bathroom to provide hot water only for the bathroom.

That's certainly one approach, but it obviously has cost (and space) implications - two boilers to buy and maintain. Also, as I have already noted, it would not be the solution if (all or part of) the underlying problem is an inadequacy in the capabilities of the mains supply/pipework.

Kind Regards, John

 

[stillp]

AFAIK the RF spectrum is covered by an EU Directive, so yes.

Fair enough, but, as had been said, I thought that individual countries had specific regulations in this respect which were more restrictive than the 'international' (EU and wider) agreements. Were that not the case, there would presumably be no need for national agencies to publish regulations such as the UK ones you recently linked to?

Kind Regards, John

If the Declaration of Conformity states that the item is a Class 1 Short Range Device, and it operates at 433 MHz, then any other restrictions are irrelevant.

 

[JohnW2]

If the Declaration of Conformity states that the item is a Class 1 Short Range Device, and it operates at 433 MHz, then any other restrictions are irrelevant.

Well, yes, of course - IF the Declaration said that, there would not be a problem. However, have you perhaps discovered something that the rest of us don't know? - as you said yourself, we don't (or, at least didn't) know what frequency it operates on.

Kind Regards, John

 

[stillp]

True, but as I said, the CE mark implies that it is intended for the European market, and the frequency 433 - 433.04 MHz is allowed to be used throughout the EEA, so it's a safer bet than the other one that was linked, which uses a frequency that is not legal in many countries of the EEA. It could of course be an illegal product with an illegal CE mark, or it could be a product that needs licensing, but why would a manufacturer not simply use the harmonised frequency?

 

[JohnW2]

True, but as I said, the CE mark implies that it is intended for the European market, and the frequency 433 - 433.04 MHz is allowed to be used throughout the EEA, so it's a safer bet than the other one that was linked, which uses a frequency that is not legal in many countries of the EEA.

Yes, I agree that it is "a safer bet" - i.e. more likley to use a frequency which is legal in the UK than the 'other one'. Indeed, we know that it can't be a less "safe bet", since the 'other one' definitely does not use a frequency permitted in the UK.

Kind Regards, John

 

[PBC_1966]

Safer bet, but we can't be sure without further details.

 

[Dave123456789]

Here is one that's also plugged but has details

http://www.ebay.co.uk/itm/Wireless-...976743?hash=item5d5a104ee7:g:GTIAAOSwqu9U24YT

Can anybody shed let on statement below:
" Digital coded signal to prevent outside interference" ???

Will this clash with alarm? "Digitally coded"??

Power supply : Receiver 230V AC, 50Hz
Battery : Transmitter 12V (23A)
Frequency: 433.92 MHz (±150kHz) - some variance in this one!
Range: 80m (Open air)

 

[JohnW2]

Can anybody shed let on statement below: " Digital coded signal to prevent outside interference" ??? Will this clash with alarm? "Digitally coded"??

It shouldn't - that's what we've been telling you. All wireless devices are (or should be!) 'digitally coded' - since, because they're all using essentially the same frequency, every transmitter would otherwise 'activate' every receiver (of whatever type!) in the neighbourhood!

Battery : Transmitter 12V (23A)

I can but presume/hope that "23A" ia a battery 'Type', not an indication that a battery capable of supplying 23 amps is required!

Kind Regards, John

 

[PBC_1966]

I suspect they meant A23 type:

http://data.energizer.com/PDFs/a23.pdf

Equivalent to Duracell's type MN21:

http://ww2.duracell.com/media/en-US...NA_DATASHEETS/MN21 Alkaline Manganese-12V.pdf

 

[JohnW2]

I suspect they meant A23 type: http://data.energizer.com/PDFs/a23.pdf

Thanks - as I said, that is what I presumed. I wonder what idiot thought up "23A" as the 'type' of a small battery?!

Kind Regards, John

 

[Dave123456789]

Ordered! Thank you gents!

 

[bernardgreen]

Can anybody shed let on statement below:
" Digital coded signal to prevent outside interference"

This means that the signal from the transmitter will only be recognised and responded to by a listening device with the same coding.

It does not mean the listening device will always respond to the transmitted signal. The receiver in the listening device may not be able to hear signals from parent transmitter when other transmitters using other coding are transmitting. The receiver will hear these signal but the decoder will not make any sense of these signals as the coding will be different to its own coding.