Re: Converting a US 300MHz RMS18/MS12A motion sensor to transmit at 433.92 MHz

[nobody@xxxxxxxxxxxx (Dave Houston)]

I should have read your article before commenting. ;)

I now see you are changing the components that control the output power.

Since you're installing a SAW resonator you won't see tuning problems but
it's easy to detune the US models just by adding a little solder.

"Stefan van der Horst" <stefan@xxxxxxxxxx> wrote:

>Hi Dave
>
>Thx for the 310 notice. I changed the article.
>
>The RF transmitter I build is 100% the same as the RF transmitter installed
>in the european MS13E motion detectors. The current and voltage provided to
>the RF module are the same as the european models. I don't have the
>equipement to test the power but I was able to span app 30 meters in open
>field and 20 meters in house through brick walls.
>
>I'll add your link to the article as well.
>
>For my purpose the rf power is high enough.
>
>"Dave Houston" <nobody@xxxxxxxxxxxx> wrote in message
>news:43c6cc5b.105778578@xxxxxxxxxxxxxxxx
>> One correction: The US frequency is 310MHz.
>>
>> You also should be aware that the FCC severely restricts the power that
>> can
>> be used by these devices. CE power limits are much higher. So while you
>> might save a bit (assuming your time has no value) this way you'll end up
>> with much less range than with the European versions. See...
>>
>>     http://www.radiometrix.co.uk/apps/apnt102.htm
>>
>> A simpler approach might be to merely disable the 310MHz circuitry and add
>> a
>> 433.92MHz RF transmitter module. There's a small 4-pin transmitter widely
>> available (Velleman, CrownHill, etc.) that will work quite well and has a
>> higher power output than the US X-10 devices.
>>
>> I've done the reverse, adding a small 310MHz transmitter to the DigiMax
>> 210
>> RF thermostat sold by X-10 Europe.
>>
>> "Stefan van der Horst" <stefan@xxxxxxxxxx> wrote:
>>
>>>Forgot to mention this is an X10 device
>>>
>>>"Stefan van der Horst" <stefan@xxxxxxxxxx> wrote in message
>>>news:dq6f7k$i30$1@xxxxxxxxxxxxxxxxxxxxxxxxxx
>>>> For those who are interested in modifying a US RMS18/MS12A to transmit
>>>> at
>>>> 433.92 MHz into I have written an tech doc for the modification. It is
>>>> located at:
>>>>
>>>> http://project.actopus.nl/X10/rms18toms13/Index.html
>>>>
>>>> regards
>>>> Stefan
>>>>
>>>
>>
>