Re: X-10 RF Freq Mod

[nobody@xxxxxxxxxxxx (Dave Houston)]

Just Another Joe <address@xxxxxxx> wrote:

>It has been stated that some low-cost RF receiver modules at 315MHz can
>be tuned to the X-10 frequency of 310MHz.
>
>My question is, can X-10 transmitters such as palmpads, slim-switches
>and motion-detectors, be [easily] tuned to 315MHz?  If so, one could
>have, for example, motion-sensors on 315MHz and controllers on 310MHz,
>to prevent one from stomping on the other.  Is that feasible?

No. X-10 transmitters are not easily tuned - most can only be tuned by
bending the wire loop that forms part of the resonant circuit and you need
sophisticated equipment to do this accurately. On the other hand, the 315MHz
superregenerative RF receivers like the ones I list on my website are easily
tuned - they have a tuning slug and a linear output that can be used as a
tuning indicator.

315MHz and 310MHz are also close enough that strong signals will be received
from either frequency by the superregenerative receivers typically used. You
need more separation.

What is feasible with something like roZetta is to use multiple receivers of
two or more well separated frequencies on serial ports, the RS485 network or
the internal receiver and use other methods to send control signals and/or
use security motion sensors, door/window switches, etc. from other systems
that use different (and well separated) frequencies.

Most of the high-end touchscreen remotes (Pronto, MX3000) use 418MHz in N.
America. They can be programmed to send control codes. It's also fairly easy
to replace the X-10 daughterboard in the universal remotes with a 4-pin
418MHz or 433.92MHz transmitter module but this is not possible with
Palmpads, Stick-a-Switches, etc. (I have a few remotes that have leads with
alligator clips that I use with various transmitters for testing and a
Pronto TS1000 to which I've added 310MHz RF.)

However, RF interference from multiple transmitters is not much of a
practical problem. PLC interference when various receivers try to send to
the powerline simulaneously is the "usual suspect".


http://davehouston.net
http://tech.groups.yahoo.com/group/roZetta/
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