First of all, congratulations on the second baby! It's never too soon
to be planning ahead, so I hope that this answer will help you.
To answer your question about non-900 MHz baby monitors, they are
harder to come by these days. But it still is possible to find
monitors that use the 49 MHz band, which usually offer shorter range
because of FCC-imposed power restrictions. But unless you live in a
mansion or you plan to listen from far outside the house, they should
be than sufficient. Almost all of them cost less than $60.
Generally speaking, any baby monitor that doesn't advertise itself as
being on the 900 MHz band or 2.4 GHz band is designed for use on the
49 MHz band. (The 2.4 GHZ models are the newest kind, but they're
more expensive than what you're looking for and usually include
Here are retail pages for some monitors that use the 49 MHz band.
Fisher-Price Sound 'n Lights at Amazon.com
Safety 1st Secure Starlight Monitor at Wal-Mart
Safety 1st Clear Connection at Epinions.com
Evenflo Constant Care at Babyant.com
OPP Soundsleep Monitor at BabyMajesty
The Fisher-Price monitors seem to get consistently positive reviews.
You can find reviews of monitors here:
Epinions.com reviews of Fisher-Price monitors
Reviews of Baby Monitors
As to your question about whether you can use two 900 MHz baby
monitors in the same home, the best answer I can give you is that you
have to try it to find out whether two particular monitors will
interfere with each other. They might, and they might not. If
they're of different brands, they very well may use different channels
and not interfere with each other (just as two adjacent TV channels
don't interfere with each other).
There are literally dozens of channels available in the 900 MHz band,
so it wouldn't be surprising if two monitors don't conflict with each
other. Some units also use something known as spread spectrum, in
which the channels rapidly change in an arbitrary fashion as a way of
reducing interference. Also, some 900 MHz units use digital modulation
and some use frequency modulation, and in that case there may limited
Keep in mind also that many cordless phones use the 900 MHz band, so
it's possible that a phone and a baby monitor could interfere with
each other, especially if they're using the same or adjacent channels.
(Some cordless phones change channels each time you use them, or look
for a vacant channel before picking one.) You also can get
interference from baby monitors or cordless phones in homes nearby.
(To complicate matters, some of the newer 2.4 GHz baby monitors can
have conflicts with wireless computer networks using the same band.)
So that takes us back to what I said earlier: The only way to really
tell if one 900 MHz baby monitor will interfere with another one (or
with a 900 MHz cordless phone) is to try it and find out. But if you
use one 900 MHz monitor and one 49 MHz monitor, you don't need to
worry (although keep in mind that some cordless phones, especially
older ones, also operate in the 49 MHz band).
Most of this information on interference has been based on personal
experience and from my knowledge as a licensed ham radio operator. You
can get an overview of wireless devices (a baby monitor isn't
electronically all that much different than a wireless phone, except
that you don't have a transmitter and receiver in the same unit) on
the following page and by following the links on it:
What does 900 MHz mean in a cordless phone?
I hope this hasn't been too confusing. Baby monitors and cordless
phones usually don't face serious problems from interference, but it's
difficult to make guarantees without having the technical data for the
precise models being used both by the consumer and by the consumer's
Best wishes, and please ask for clarification if I've been too
confusing in providing this technical information.
Google search terms:
reviews "baby monitors"
"49 mhz" "baby monitors"